REPORTS OF THE COORDINATORS
Overall coordinatorÕs report
Udda Lundqvist
Nordic Genetic Resource Center
P.O.
Box 41, SE 230 53 Alnarp, Sweden
e-mail:
udda.lundqvist@nordgen.org
First of all I have to
inform the barley community the sad news that our dear friend Robert (Bob)
Nilan passed away in Pullman, Washington State, USA, October 7th, 2015, with
him USA and the whole barley community has lost a pioneer within plant breeding
and plant genetic research especially barley. One of his proudest achievements
during his long career was the establishment of the International Barley
Genetics Symposia (IBGS) that are still taking place. The first symposium was
organized 1963, in Wageningen, the Netherlands, but the second IBGS, Bob had
the pleasure and opportunity to organize himself in Pullman, USA, 1969. He
could participate in 10 of the symposia, but unhappily he was not able to make
it to the eleventh in China, 2012, because of health troubles. He greatly
contributed to establish the Barley Genetics Newsletter where the first issue
appeared in 1971 and with this issue BGN has been published for 45 years. You can
read more in the memorium written in this BGN 45:1-3.
In a few weeks the 12th
International Barley Genetic Symposium will take place in Minneapolis, in the
midwest of the United States, June 26-30, 2016. I do hope that many of the
barley community people have the possibility to participate in this important
event. Like in the last symposium in Hangzhou, China, 2012, a workshop on
ÒBarley Genetic stocks, there Use and PotentialÓ will be organized Tuesday
evening, June 28th. Several important topics will be discussed, i.e.
Developmental Mutants in Barley, Characterization and Use. The future of
publishing Barley Genetics Newsletter will be a very important discussion
topic. There will not be a special workshop for the coordination for several
important barley mutant collections as we had in previous meetings, these
discussions will get included in the above mentioned workshop as a special
topic.
Since the last overall
coordinatorÕs report in BGN 44 not too many exciting news have happened. Again,
no research report has been received for this issue. Once again I want to
stress the importance of publishing short research notes after having been
published in high level journals. The barley community should gain very much
what different barley research groups are working on and receiving new results
to investigate the whole barley genome.
In this volume, BGN 45,
again one hundred and twenty-two stock descriptions are described, revised or
updated with latest research results and citied literature. They are listed in
table 1, additionally also tables 2 and 3, with BGS numbers in order (table 2)
and in alphabetic order of the recommended locus names and symbols (table3) are
again published to make it easy for barley researchers to find gene
descriptions. The construction of the ÔInternational Database for Barley Genes
and Barley Genetic StocksÕ is happily proceeding fast and will be presented in
a modern and easy to handle version. Hopefully it will be ready for
demonstration at the IBGS in June 2016..
Some
different barley genetic stock characters.
List of Barley Coordinators
Barley Genetics Stock Center: Harold Bockelman, USDA-ARS, National Small Grains
Germplasm Research Facility, 1691 S. 2700 W., Aberdeen, ID 83210, USA. FAX: +1
208 397 4165; e-mail: <nsgchb@ars-grin.gov>
Trisomic and aneuploid stocks: Harold Bockelman, USDA-ARS, National Small Grains Germplasm
Research Facility, 1691 S. 2700 W., Aberdeen, ID 83210, USA. FAX: +1 208 397
4165; e-mail: <nsgchb@ars-grin.gov
>
Translocations and balanced tertiary
trisomics: Andreas Houben,
Institute of Plant Genetics and Crop Plant Research, Corrensstrasse 3, DE-06466
Stadt Seeland, OT. Gatersleben, Germany. FAX: +49 39482 5137; e-mail: <houben@ipk-gatersleben.de>
Desynaptic genes: Andreas Houben, Institute of Plant Genetics and Crop
Plant Research, Corrensstrasse 3, DE-06466 Stadt Seeland, OT Gatersleben,
Germany. FAX: +49 39482 5137; e-mail: <houben@ipk-gatersleben.de>
Autotetraploids: Wolfgang Friedt, Institute of Crop Science and Plant
Breeding, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, DE-35392 Giessen,
Germany. FAX: +49 641 9937429; e-mail: <wolfgang.friedt@agrar.uni-giessen.de>
Disease and pest resistance genes: Frank Ordon, Julius KŸhn Institute (JKI), Institute
for Resistance Research and Stress
Tolerance, Erwin-Baur-Strasse 27, DE-06484 Quedlinburg, Germany. e-mail: <frank.ordon@jki.bund.de>
Eceriferum genes: Udda
Lundqvist, Nordic Genetic Resource Center (NordGen), SmedjevŠgen 3,
SE-230 53 Alnarp, Sweden; e-mail: < udda.lundqvist@nordgen.org>
Chloroplast genes: Mats Hansson, Lund
University, Department of Biology, Sšlvegatan 35B, SE-22362 Lund, Sweden.
e-mail: <mats.hansson@biol.lu.se>
Ear morphology genes: Udda Lundqvist, Nordic Genetic Resource Center
(NordGen), SmedjevŠgen 3,
SE-230
53 Alnarp, Sweden; e-mail: < udda.lundqvist@nordgen.org>
and
Antonio
Michele Stanca: Department of Agricultural and Food Science, University of
Modena and Reggio Emilia, Reggio Emilia, Italy. FAX +39 0523 983750, e-mail: michele@stanca.it
and
Valeria
Terzi: CRA-GPG, Genomics Research Centre, Via Protaso 302, IT-29017 Fiorenzuola
dÕArda (PC), Italy. e-mail: <valeria.terzi@crea.gov.it>
Semi-dwarf genes: Jerome D. Franckowiak, Department of Agronomy
and Plant Genetics, University of Minnesota Twin Cities, 411 Borlaug Hall, 1991
Upper Buford Circle, St Paul, MN 55108, USA. e-mail: <jfrancko@umn.edu>
Early
maturity genes: Udda Lundqvist, Nordic
Genetic Resource Center (NordGen), SmedjevŠgen 3,
SE-230 53 Alnarp, Sweden; e-mail: <udda.lundqvist@nordgen.org>
Barley-wheat genetic stocks: A.K.M.R. Islam, Department of Plant Science, Waite
Agricultural Research Institute, The University of Adelaide, Glen Osmond, S.A.
5064, Australia. FAX: +61 8 8303 7109; e-mail: <akm.islam@adelaide.edu.au>
Barley Genetic Stocks (GSHO – Genetic Stocks (Hordeum)
in the
USDA-ARS National Small Grains Collection
H.E. Bockelman
USDA-ARS-NSGC
1691 S. 2700 W.
Aberdeen, ID 83210 USA
e-mail:Harold.Bockelman@ars.usda.gov
GSHO
Distributions – January 1, 2015 to March 24, 2016.
A total of 1,115 GSHO accession samples were
distributed in 63 separate requests to scientists in 10 countries (Australia,
China, Czech Republic, Germany, Japan, Republic of Korea, Morocco, Poland,
United Kingdom, and United States).
Voucher Images
High
resolution scans of kernels of most GSHO accessions have been attached to the
accession records as voucher images.
They are viewable on the GRIN-Global search page: https://npgsweb.ars-grin.gov/gringlobal/search.aspx
New Accessions
Dr.
Andris Kleinhofs has donated additional mutant stocks and GSHO numbers have
been assigned as follows.
Table 1.
|
GSHO Number |
Mutant name |
Symbol |
|
3671 |
Multiovary 5.o |
mov5.o |
|
3672 |
Multiovary 4.m |
mov4.m |
|
3673 |
Multiovary.n |
mov.n |
|
3674 |
Short awn 6.q |
lks6.q |
|
3675 |
Unbranched style 5.e |
ubs 5.e |
|
3676 |
Unbranched style 5.f |
ubs5.f |
|
3677 |
Uniculme 3.m |
cul3.m |
|
3678 |
Low number of tillers
1.b |
Int1.b |
|
3679 |
Waxy spike 1.b |
wxs1.b |
|
3680 |
Waxy spike 1.c |
wxs1.c |
|
3681 |
Waxy spike 1.d |
wxs1.d |
|
3682 |
Albino lemma 1.d |
alm1.d |
Table
1 continued.
|
GSHO number |
Mutant name |
Symbol |
|
3683 |
Albino lemma 1.e |
alm1.e |
|
3684 |
Fenoxaprop-p-ethyl reaction 1 |
fxp1 |
|
3685 |
Single internode dwarf 1.c |
sid1.c |
|
3686 |
Many noded dwarf 7.h |
mnd7.h |
|
3687 |
Ovaryless
3.c |
ovl3.c |
|
3688 |
Male sterile genetic.ou |
msg.ou |
|
3689 |
Male sterile genetic.ov |
msg.ov |
|
3690 |
Male sterile genetic.ow |
msg.ow |
|
3691 |
Male sterile genetic.ox |
msg.ox |
|
3692 |
Male sterile genetic.oy |
msg.oy |
CoordinatorÕs
report: Translocations and balanced tertiary trisomics
Andreas
Houben
D-06466
Stadt Seeland, OT Gatersleben Germany
e-mail: houben@ipk-gatersleben.de
The 3HS.3BL spontaneous
Robertsonian translocation obtained from the progenies of wheat-barley (Chinese
Spring x Betzes) hybrids backcrossed with wheat line Mv9kr1 was transferred
into the modern Martonvasar wheat cultivar Mv Bodri by Tukosi et al. (2014). The translocation was
identified with molecular cytogenetic methods. Fluorescence in situ
hybridization using barley subtelomeric (HvT01) and centromere-specific
[(AGGGAG)4] repetitive DNA probes confirmed that the complete barley chromosome
arm was involved in the Robertsonian translocation. The wheat-specific
repetitive DNA probes identified the presence of the whole wheat genome, except
the short arm of the 3B chromosome. Genotypes homozygous for the centric fusion
were selected, after which morphological analysis was performed on the plants
and the yield components were measured in the field during two consecutive
vegetative seasons. The introgression of the 3HS.3BL translocation into the
modern wheat cultivar Mv Bodri significantly reduced the plant height due to
the incorporation of the dwarfing allele RhtD1b. The presence of the 3HS.3BL
translocation in the Mv9kr1 and Mv Bodri wheat background improved tillering
and seeds per plant productivity in field experiments carried out in
Martonvasar and Keszthely, Hungary.
The
collection is being maintained in cold storage. To the best knowledge of the
coordinator, there are no new publications dealing with balanced tertiary
trisomics in barley. Limited seed samples are available any time, and requests
can be made to the coordinator.
References:
Turkosi E, A. Farkas,
N:R. Aranyi, B. Hoffmann, V. Toth, and M. Molnar-Lang.
(2014) Improvement of the agronomic traits of a wheat-barley centric fusion by
introgressing the 3HS.3BL translocation into a modern wheat cultivar. Genome 57
(11-12):601-607.
CoordinatorÕs
Report: Desynaptic Genes
Andreas
Houben
D-06466
Stadt Seeland, OT Gaterslebem, Germany
e-mail: houben@ipk-gatersleben.de
The status of this
genetic stock collection described in BGN 42 did not change.
No work was published
describing the application of one of the desynaptic mutants.
However, a novel method suitable to quantify recombination events
in barley was described by Dreissig et
al. (2015). The authors investigated the feasibility of using flow-sorted
haploid nuclei, Phi29 DNA polymerase-based whole-genome-amplification (WGA) and
multi-locus KASP-genotyping to measure meiotic crossovers in individual barley
pollen grains. To demonstrate the proof of concept, 24 gene-based physically
mapped single nucleotide polymorphisms were used to genotype the WGA products
of 50 single pollen nuclei. The number of crossovers per chromosome,
recombination frequencies along chromosome 3H and segregation distortion were analysed
and compared to a doubled haploid (DH) population of the same genotype. The
number of crossovers and chromosome wide recombination frequencies show that
this approach is able to produce results that resemble those obtained from
other methods in a biologically meaningful way. Only the segregation distortion
was found to be lower in the pollen population than in DH plants.
In many cereal crops, meiotic
crossovers predominantly occur toward the ends of chromosomes and 30 to 50% of
genes rarely recombine. This limits the exploitation of genetic variation by
plant breeding. Previous reports demonstrate that chiasma frequency can be
manipulated in plants by depletion of the synaptonemal complex protein ZIPPER1
(ZYP1) but conflict as to the direction of change, with fewer chiasmata
reported in Arabidopsis thaliana and more crossovers reported for rice.
Barakate et al. (2014) used RNA
interference (RNAi) to reduce the amount of ZYP1 in barley to only 2 to 17% of
normal zygotene levels. In the ZYP1(RNAi) lines, fewer than half of the
chromosome pairs formed bivalents at metaphase and many univalents were
observed, leading to chromosome nondisjunction and semi-sterility. The number
of chiasmata per cell was reduced from 14 in control plants to three to four in
the ZYP1-depleted lines, although the localization of residual chiasmata was
not affected. DNA double-strand break formation appeared normal, but the
recombination pathway was defective at later stages. A meiotic time course
revealed a 12-h delay in prophase I progression to the first labeled tetrads.
Barley ZYP1 appears to function similarly to ZIP1/ZYP1 in yeast and
Arabidopsis, with an opposite effect on crossover number to ZEP1 in rice,
another member of the Poaceae.
The process of meiosis results
in the formation of haploid daughter cells, each of which inherit a half of the
diploid parental cells' genetic material. The ordered association of homologues
(identical chromosomes) is a critical prerequisite for a successful outcome of
meiosis. Homologue recognition and pairing are initiated at the chromosome
ends, which comprise the telomere dominated by generic repetitive sequences,
and the adjacent subtelomeric region, which harbours chromosome-specific
sequences. In many organisms telomeres are responsible for bringing the ends of
the chromosomes close together during early meiosis, but little is known
regarding the role of the subtelomeric region sequence during meiosis. Calderon
Medel et al. (2014) report the
observation of homologue pairing between a pair of Hordeum chilense chromosomes lacking the subtelomeric region on one
chromosome arm indicates that the subtelomeric region is important for the
process of homologous chromosome recognition and pairing.
Phillips et al. (2015) work examines whether crossovers can be shifted to
more proximal regions simply by elevating growth temperature. We utilised a
genome-wide marker set for linkage analysis combined with cytological mapping
of crossover events to examine the recombination landscape of plants grown at
different temperatures. We found that barley shows heterochiasmy, that is,
differences between female and male recombination frequencies. In addition, we
found that elevated temperature significantly changes patterns of recombination
in male meiosis only, with a repositioning of Class I crossovers determined by
cytological mapping of HvMLH3 foci. We show that the length of synaptonemal
complexes in male meiocytes increases in response to temperature. The results
demonstrate that the distribution of crossover events are malleable and can be
shifted to proximal regions by altering the growth temperature. The shift in
recombination is the result of altering the distribution of Class I crossovers,
but the higher recombination at elevated temperatures is potentially not the
result of an increase in Class I events (Phillips et al 2015).
References:
Barakate A, J.D. Higgins, S. Vivera, J. Stephens,
R.M. Perry, L. Ramsay, I. Colas, H. Oakey, R. Waugh, F. C.Franklin, S.J. Armstrong,
and C. Halpin. 2014. The synaptonemal complex protein ZYP1 is required for
imposition of meiotic crossovers in barley. Plant Cell 26 (2):729-740.
doi:10.1105/tpc.113.121269.
Calderon Mdel C, M. D. Rey, A. Cabrera, and P. Prieto. 2014. The subtelomeric region
is important for chromosome recognition and pairing during meiosis. Scientific
reports 4:6488. doi:10.1038/srep06488.
Dreissig S, J. Fuchs, P. Capal, N. Kettles,
E. Byrne, and A. Houben. 2015. Measuring Meiotic Crossovers via Multi-Locus Genotyping of
Single Pollen Grains in Barley. Plos One 10 (9). doi:ARTN e0137677.
Phillips D, G. Jenkins, M. Macaulay, C. Nibau,
J. Wnetrzak, D. Fallding, I. Colas, H. Oakey, R. Waugh, and L. Ramsay.
2015. The effect of temperature on
the male and female recombination landscape of barley. New Phytol 208
(2):421-429. doi:10.1111/nph.13548.
CoordinatorÕs report: Eceriferum
genes
Udda Lundqvist
Nordic Genetic Resource Center (Nordgen)
P.O.
Box 41, SE-230 53 Alnarp, Sweden
e-mail: udda.lundqvist@nordgen.org
Presence of wax coating
and its composition is an important feature of the barley plant. It reduces
evaporation of water from the plant and helps protect it against pathogens. The
waxless Eceriferum and glossy mutants
affect the presence and type of epicuticular waxes on the different organs.
Many different surface wax mutants have been isolated as induced or spontaneous
mutants and much research has been done during the last century both
genetically and biochemically. All 79 defined loci are published as descriptions
in Barley Genetics Newsletter (BGN) 42, later issues and some of them also
updated in this volume. All descriptions are valid and up-to-date.
One allele of all the 79
gene loci have been backcrossed to a common genetic background the cultivar ÔBowmanÕ
by J.D. Franckowiak, USA. They are available as Near Isogenic Lines (NIL) at
the Nordic Genetic Resource Centre (NordGen), Sweden, www.nordgen.org
and at the Small Grain Germplasm Research Facility (USDA–ARS), Aberdeen,
ID 83210, USA, nsgchb@ars-grin.gov. But be aware of that
many of the lines are a more advanced backcross derived line incorporated at
NordGen than those at the Small Grain Research Facility in Aberdeen. The
material in Sweden is well phenotyped and gets regenerated continuously.
Since the 1970s three
with the highest numbers of alleles in the Eceriferum
genes, cer-c, cer-q and cer-u with 215,
167 and 160 alleles, respectively,
located in chromosome 2HS, very tightly linked, are discussed intensively.
These genes affect the epicuticular wax coating on the spike and leaf sheath.
They have been of large interest all the time. Intensive discussions were going
on if it is one cluster gene, cer-cqu,
or three different ones. Among all allele tested mutants in this region 13 were
found to be multiple ones, among them 7 triple mutants. Mutations reverting in
one step to wax formation have also occurred.
Schneider et al. (2016) report that recently
developed genomic resources and mapping populations in barley defined the
cluster gene cer-cqu to a small
region on chromosome arm 2HS. Sequencing more than 50 independent mutants for
each gene confirmed their identification. Cer-c
is a chalcone synthase-like polyketide synthase, designated diketone synthase. Cer-q is a chalcone/carboxyl transferase
and Cer-u is a P450 enzyme. A
physical map revealed the order Cer-c,
Cer-u and Cer-q with the flanking genes 101kb apart, confirming that they are
a gene cluster, Cer-cqu.
Homology-based modeling suggests that many of the mutant alleles affect overall
protein structure or specific active site residues. By constructing several F2
mapping populations between the Near Isogenic Lines (NIL) BW 409 (gsh6.s allele, a mutation in the cer-c gene), BW 404 (gsh1.a, an allele in the cer-q gene) and BW 411 (gsh8.ag, an allele in the cer-u gene) and several cultivars
defined in this SNP marker analyses the location of Cer-c, Cer-q and Cer-u to
an interval flanked by distal marker 1_0718 and proximal marker 1_1059. After
selecting candidate genes all results provide strong evidence that MLOC_59804, MLOC_13397 and AK373499
encode CER-C, -Q and U, respectively. Thus the cer-c mutants that are caused by
mutations in the CHS-like synthase encoded MLOC_59804,
analysis of the mutants across the MLOC_13397
model supports that cer-q encodes a
lipase, and finally analysis supports the conclusion that AK373499 (Cer-u) encodes
a cytochrome P450. Finally the
conclusion stated that cer-c, cer-q and cer-u are three different independent gene loci but very closely
linked.
Li, Chao et al. (2015)
reported on the characterization of epicuticular wax coating and genetic
mapping of the eceriferum-ym (cer-ym) locus. The cer-ym mutant showed abnormally strong glossy spikes, sheaths and
leaf blades. The mutant leaves showed a substantial reduction in the amounts of
the major cutin monomers and a high increase in the main wax component. It is a
semi-dwarf phenotype, a cutin defective mutant and is similar to the phenotype
of Bowman-Near Isogenic line carrying the cer-zv.268
allele, known as a cuticular recessive mutant. Analysis of Bowman-Near isogenic
line BW 144 (cer-ym.753) compared
with its wild barley accession ÔOUH602Õ mapped the gene to chromosome 4H,
co-segregated with AK364461 which is a marker that co-segregates with cer-zv in the pericentromeric region. Cer-ym was mapped within a 0.8 cm
interval between EST marker AK370363 and AK251484. In conclusion cer-ym is located on chromosome 4H in
the pericentromeric region which is
very important for cuticle development.
Li, C. et al. (2012) reports on
cuticle-associated genes that are protected by a cuticle against abiotic and
biotic stresses. A better understanding of the determination of cuticle
formation and function has the potential to contribute to the breeding of more
drought tolerant and disease resistant crop cultivars. It was suggested by
microarray analysis that some barley homologs have expression in epidermis of
elongation zone of leaves where wax synthesis happens. The research
demonstrates to facilitate the cloning of such genes. They found a case of
complete linkage between an eceriferum
(cer) locus and a known
cuticle-associated gene: HvCER6 of Arabidopsis thaliana and eceriferum-zg (cer-zg). This gene is affecting the epiticular wax coating on the
leaf blades but reduced and only on the three upper leaves. It is located on
chromosome 4H. CER6 encodes an elongase
condensing enzyme involved in the synthesis of very long chain fatty acid
precursors. The data show therefore suggestive that CER-ZG might be the homolog of AtCER6.
The phenotypes of atcer6 and cer-zg mutants were similar to one
another, therefore they suggest that HvCER6
is the candidate gene of CER-ZG.
References:
Li, C., X. Ma, A. Wang, E. Nevo, and
G. Chen. 2012. Genetic Mapping of Cuticle-associated Genes in
Barley. Cereal Research Communications. DOI: 10.1556/CRC.2012.0020.
Li, Chao, Ch. Liu, X. Ma, A. Wang, R.
Duan, Ch. Nawrath,
T. Komatsuda, and G. Chen. 2015. Characterization and
genetic mapping of eceriferum-ym (cer-ym),
a cutin deficient barley mutant with impaired leaf water retention capacity.
Breeding Science 65:327-332.
Schneider, L M., N. M. Adamski, C.E.
Christensen, D. B. Stuart, S. Vautrin, M. Hansson, C. Uauy, and P. von
Wettstein-Knowles. 2016. The Cer-cqu gene cluster determines
three players in a β-diketone synthase polyketyde pathway synthesizing
aliphatics in epicuticular waxes. Journal of Experimental Botany Advance
Access. Doi:10.1093/jxb/erw105.
BW409 (gsh6.s) to the left compared
with cultivar Bowman
BW404 (gsh1.a) mutant to the
left
compared with cultivar Bowman
Eceriferum-zg (cer-zg) leaf blade to the left
compared with cultivar Bowman
BW 144 (cer-ym.753) mutant to
the left
compared with cultivar
Bowman,
showing water drops on seedlings
Coordinator«s Report: Disease and Pest resistance genes
Caroline Breidenbach and Frank
Ordon
Julius KŸhn-Institute (JKI)
Institute for Resistance Research and
Stress Tolerance
Erwin-Baur-Str. 27
D-06484 Quedlinburg, Germany
e-mail:
frank.ordon@jki.bund.de
In the table below you will find papers published in 2015 extending last
year ́s list of information available on molecular markers for major
resistance genes in barley published in Barley Genetics Newsletter 44.
List of papers published on mapped major resistance
genes in barley updated until December 21, 2015
|
Resistance
gene |
Chromsomal
location |
Reference(s) |
|
|
Puccinia graminis |
|||
|
Rpg5 |
5H |
Dracatos et al.
2015b, Mamo et al. 2015 |
|
|
rpg4 |
5H |
Mamo et al.
2015 |
|
|
Puccinia hordei |
|||
|
Rph3 |
7H |
GutiŽrrez et al. 2015 |
|
|
Rph20 |
5H |
Dracatos et al. 2015a |
|
|
Rph22 |
2H |
Johnston et al. 2015 |
|
|
Rph23 |
7H |
Singh et al. 2015, Dracatos et al. 2015a |
|
|
Rynchosporium commune |
|||
|
Rrs1 |
3H |
Looseley et al. 2015 |
|
|
Pyrenophora teres |
|||
|
Rpt4 |
7H |
Tamang et al. 2015 |
|
|
Rpt6 |
5H |
Tamang et al. 2015 |
|
|
Rpt7 |
|
Tamang et al. 2015 |
|
|
Ustilago nuda |
|||
|
Un8 |
1H |
Zang et al. 2015 |
|
|
Barley
yellow mosaic virus (BaYMV), Barley mild mosaic virus (BaMMV) |
|||
|
Rym16Hb |
2H |
Johnston et al. 2015 |
|
Dracatos, P., D. Singh,
U. Bansal, and R.F. Park, 2015a. Identification
of new sources of adult plant resistance to Puccinia
hordei in international barley (Hordeum
vulgare L.) germplasm. Eur J Plant Pathol 141: 463-476.
Dracatos, P., D. Singh, T. Fetch, and R. Park, 2015b. Resistance to Puccinia graminis f.sp avenae in barley
is associated with the Rpg5 Locus. Phytopathology105: 490-494.
GutiŽrrez, L., S.
Germ‡n, P.M. Hayes, C.A. PŽrez, F. Capettini, A. Locatelli, N.A. Berberian,
E.E. Falconi, R. Estrada, D. Fros, V. Gonza, H. Altamirano, J. Huerto-Espino,
E. Neyra, G. Orjeda, S. Sandoval-Islas, R. Singh, K. Turkington, and A.J.
Castro, 2015. Multi-environment multi-QTL
association mapping identifies disease resistance QTL in barley germplasm from
Latin America. Theor. Appl Genet 128: 501-516.
Johnston, P.A., V.
Meiyalaghan, M.E. Forbes, A. Habekuss, R.C. Butler, and R. Pickering, 2015. Marker assisted separation of resistance genes Rph22 and Rym16Hb from
an associated yield penalty in a barley: Hordeum
bulbosum introgression line. Theor Appl Genet 128: 1137-1149.
Looseley, M.E., R.
Keith, D. Guy, G. Barral-Baron, A. Thirugnanasabandam, D. Harrap, P. Werner,
and A.C. Newton, 2015. Genetic mapping of
resistance to Rhynchosporium commune and characterization of early infection in
a winter barley mapping population. Euphytica 203: 337-347.
Mamo, B.E., K.E. Smith,
R.S. Brueggeman, and B.J. Steffenson, 2015. Genetic
characterization of resistance to wheat stemm rust race TTKSK in landrace and
wild barley accessions identifies the rpg4/Rpg5 locus. Phytopathology 105: 99-109.
Singh, D., P. Dracatos, L.
Derevnina, M. Zhou, and R.F. Park, 2015. Rph23: A new designated additive adult plant
resistance gene to leaf rust in barley on chromosome 7H. Plant Breeding 134:
62-69.
Tamang, P., A. Neupane, S. Mamidi,
T. Friesen, and R. Brueggeman, 2015. Association mapping of
seedling resistance to spot form net blotch in a world wide collection of
barley. Phytopathology 105: 500-508.
Zang, W., P.E. Eckstein,
M. Colin, D. Voth, A. Himmelbach, S. Beier, N. Stein, G.J. Scoles, and A.D.
Beattie, 2015. Fine
mapping and identification of a candidate gene for the barley Un8 true loose
smut resistance gene. Theor Appl Genet 128: 1343-1357.
CoordinatorÕs report: Nuclear genes affecting the chloroplast
Mats Hansson
Lund University,
Department of Biology,
Sšlvegatan 35B,
SE-22362 Lund,
Sweden
E-mail: mats.hansson@biol.lu.se
Barley
chlorophyll mutants have been named albina,
xantha, viridis, chlorina, tigrina and striata depending on their colour and colour pattern. In the albina mutants the leaves are completely
white due to lack of both chlorophyll and carotene pigments. The xantha mutants are yellow and produce
carotene, but no chlorophyll. The chlorina
and viridis mutants are both pale
green, but differ in chlorina being
viable. The tigrina and striata mutants are stripped transverse
and along the leaves, respectively.
The fifth ring of the
chlorophyll molecule is formed by the cyclase, which is the least known enzyme
in the chlorophyll biosynthetic pathway. So far, only one subunit has been
identified, encoded by Xantha-l in
barley. Staccanella et al. (2015) used Arabidopsis mutants as well as the
barley mutants viridis-k.23, viridis-k.170, viridis-zb.63 and xantha-l.35
to suggest that plastoquinol might function as an electron donor for the
cyclase reaction.
Barley mutant chlorina-f.104 was explored in a study concerning a chloroplastic
protein with an NmrA domain, cpNrp (Brestic et
al. 2015). The NmrA domain serves as a receptor for oxidized NAD+/NADP+
and the ability to discriminate between their oxidized and reduced forms may be
linked to a possible role in redox sensing. The mutant chlorina-f.104 shows a modified structure of the light-harvesting
antennae and offered a useful system to examine the factors that determine the
photosynthetic performance in leaves (Brestic et al. 2015). It was suggested that cpNrp is a member of a new
protein family and can serve as a chloroplastic redox receptor.
The stock list of barley mutants defective in chlorophyll biosynthesis and chloroplast development is found in Barley Genetics Newsletter issue 37 (2007): 37-43. Seeds of most mutants listed can be obtained from Mats Hansson (http://www.biology.lu.se/mats-hansson).
New references:
Brestic, M.,
M. Zivcak, M. Datko, K. Olsovska, O. Sytar and H. Shao. 2015. Novel resistance mechanism of barley chlorina f104 antenna mutant
against photoinhibition: possible role of new identified chloroplasticn cpNrp protein. Theor. Exp. Plant
Physiol. 27: 75-85.
Steccanella,
V., M. Hansson and P. E. Jensen. 2015. Linking
chlorophyll biosynthesis to a dynamic plastoquinone pool. Plant Physiol.
Biochem. 97: 207-216.
CoordinatorÕs report: Early maturity and
Praematurum genes
Udda Lundqvist
Nordic Genetic Resource Center (NordGen)
SmedjevŠgen
3
SE-23
053 Alnarp, Sweden
e-mail: udda.lundqvist@nordgen.org
The
demand for early maturity in barley has become an important goal for plant
breeding during the last century. Time of flowering has an important impact on
yield and has been a key trait in the domestication of crop plants worldwide.
Early maturity material has been collected in different geographic regions and
climate conditions, today a critical issue in times of global warming. Many
different early maturity and Praematurum mutants are isolated in many
different cultivars, and they are stored in Gene banks in several parts of the
world. Only in Scandinavia about 1250 different mutants have been isolated,
their phenotypes described, analysed genetically and used in plant breeding
worldwide. The Praematurum mutants
are grouped into three categories according to their heading and maturity time
with a variation between one and ten days: (1) drastically altered earliness;
(2) medium increase of earliness; (3) slightly modified earliness. Long term
studies made it possible to identify 10 early maturity (eam) and 9 Praematurum (mat) loci, among them also day-length
neutral ones. All identified gene loci are incorporated into a common
background, the barley cultivar ÔBowmanÕ by J.D. Franckowiak, USA, and he
established Bowman backcross derived lines (Near Isogenic Lines, ÔNILÕ). All
these early maturity lines are well phenotyped, documentated and long-time
stored in NordGen, Alnarp, Sweden. They are very important and useful for
intensive molecular studies, cloning genes and understanding the barley genome.
Cultivated
barley (Hordeum vulgare L. subsp. vulgare),
like most temperate cereal crops, is a long day plant with two growth types,
spring and winter. The growth habit is determined by the interaction of two
genes; Vrn-H2, a strong inhibitor of
flowering under long day conditions and Vrn-H1
(also known as HvVRN1). Phytochromes
play an important role in light signalling and photoperiodic control of
flowering time in plants. Pankin et al.
(2014) reported mapping and sequencing a candidate gene for the Early maturity 5 (Eam5) locus. The Bowman Near-Isogenic Line having the Eam5 allele is early flowering under
both short and long day conditions, and the genetic interaction with the major
barley photoperiod response gene Ppd-H1
were analysed. The Eam5 gene was originally
located on chromosome 5H and originated from an ICARDA/CYMMIT selection. They
suggested that the red/far-red light photoreceptor HvPhytochrome C (HvPHYC) is a candidate underlying the early maturity 5 locus. They fine mapped the gene using a mapping-by-sequencing
approach applied on the whole-exome capture data from bulked early
flowering segregates derived from the backcrossed-derived Bowman line. They
show that the Eam5 gene disrupts
circadian expression of clock genes, it also interacts with the major
photoperiod response gene Ppd-H1 to
accelerate flowering under non-inductive short days. They suggest that HvPHYC participates in transmission of
light signals to the circadian clock and thus modulates light-dependent
processes such as photoperiodic regulation of flowering.. It also showed that HvPHYC carried a nonsynonymous mutation
in the NIL Bowman line for Eam5 which
causes the missense substitution that leads to a change of the hydrophobic
phenylalanine to the hydrophilic serine (mutation F380S). Therefore they
proposed that HvPHYC as the candidate
gene for Eam5. They also found
according to their segregation analysis that both Vrn-H1 and HvPHYC were
tightly linked to the early flowering phenotype.
Nishida
et al. (2013) reported on different
flowering time genes. The spring-type near isogenic line (NIL) of the
winter-type barley (Hordeum vulgare ssp.
vulgare) var. Hayakiso 2 (HK2) was developed by introducing VERNALIZATION-H1 (Vrn-H1) for spring
growth habit from a spring-type var. Indo Omugi. Contrary to expectations, the
spring-type NIL line flowered later than winter-type HK2. They stated that this
phenotype difference was controlled by a single gene, which co-segregated only
with phytochromeC (HvPhyC) which is one
of the candidates around the Vrn-H1
region (Vrn-H1, HvPhycC and CASEIN KINASE
IIα). That indicated that HvPhyC
was the most likely candidate gene for flowering time. Compared with the late
flowering allele HvPhyC-l from NIL,
the early-flowering allele HvPhyC-e
from HK2 had a single nucleotide polymorphism T1139C in exon 1, which caused a
nonsynonymous amino acid substitution of phenylalanine
at position 380 by serine in the functionally essential GAF domain. Functional
assay using a rice (Oryza sativa) PhyA phyC double mutant line showed that
both of the HvPhyC alleles are
functional, but HvPhyC-e have a
hyperfunction. Expression analyses using NILs carrying HvPhyC-e and HvPhyC-l,
respectively, showed that HvPhyC-e
up-regulated only the flowering promoter FLOWERING
LOCUS T1 by bypassing the circadian clock genes and flowering integrator CONSTANS1 under a long photoperiod.
There were no apparent differences in HvPhyC
expression between NIL (HvPhyC-e) and
NIL (HvPhyC-l), despite their allelic
differences. In both of the NILs, HvPHyC
was expressed all day and seemed to show diurnal fluctuation under both long
and short photoperiod conditions with the trend that it was up-regulated around
dusk and down-regulated during the day. They also stressed in addition to the
above mentioned genes, novel gene resources for early flowering will be
important to elucidate the genetic mechanism of the flowering time and future
breeding programs. Recent comparative studies in genetic pathways for flowering
revealed that temperate grass species share a similar gene set with dicot
species Arabidopsis, especially for
photoperiodic pathways.
References:
Nishida, H., D. Ishihara, M. Ishii,
T. Kaneko, H. Kawahigashi. Y. Akashi, D, Saisho, K. Tanaka, H. Handa, K.
Takeda, and K. Kato. 2013. Phytochrome
C is a key factor controlling long-day flowering in barley. Plant Physiol.
163:804-814.
Pankin, A., C. Campoli, X. Dong, B.
Kilian, R. Sharma, A. Himmelbach, R. Saini, S.J. Davis, N. Stein, K. Schneeberger,
and M. von Korff. 2014. Mapping-by-sequencing Identifies HvPHYTOCHROME C as a candidate gene for
the early maturity 5 Locus modulating
the circadian clock and photoperiodic flowering in barley. Genetics
198:383-396.
CoordinatorÕs
report: ear morphology genes
Michele
Stanca
Department of Life Science, UNIMORE - Reggio Emilia, Italy
Valeria
Terzi
CREA-GPG, Genomics Research Centre, Fiorenzuola dÕArda, Italy
Barley today ranks
fourth behind wheat, rice and maize among the world's cereals for the
importance of its contribution, whether direct or indirect, to the production
of food. The global production is estimated in 2015 in 135 millions of metric
tons (Mt) in a harvested area of 50 millions of hectares with an average grain
yield of 2.7 t/ha.
Barley spike is one of
the important source of food for humans and it has been estimated that barley
production needs to increase to meet demand of increasing population. This
means that the grain number of the barley spike must be improved in the near
future, together with the biomass increase. As reported in previous Barley
Genetic Newsletter (BGN) reports, grain number enhancement can be theoretically
obtained through modifications of the spike fertility and morphology. Due to
the implications in grain production and yield, the genetic dissection of the
developmental plan of this storage sink is therefore of outstanding relevance
to design the barley for the future in which innovative traits can be
implemented through pre-breeding strategies.
Barley developmental
mutants can be a Mendelian solution to identify genes controlling key steps in
the establishment of the spike morphology. Large
collections of natural and induced mutants have been developed since the 1920s,
with the aim of understanding developmental and physiological processes and
exploiting mutation breeding in crop improvement. The collections are
comprehensive not only of single Mendelian spike mutants, but even of double
and triple mutants obtained by intercrossing simple mutants. In recent years
the integration of the most advanced omic technologies with the historical
mutation-genetics research helped in the isolation and validation of some of
the genes involved in spike development. Interestingly, some genes known from
long time to be responsible for mutant phenotype have been recently cloned and
functionally characters. Several of these genes are involved in mutations that,
selected by ancient farmers, transformed wild plants in domesticated ones,
giving a major contribution to the development of early agrarian societies. The
most important trait selected by humans during the barley domestication process
and related to the evolution of barley spike is the transformation of brittle
into non-brittle spike. Loss of the natural mode of grain dispersal was perhaps
the most important single event in this process. At maturity, the spike in wild
(i.e. ancestral) barley forms ÔÔconstriction groovesÕÕ and disarticulates at
each rachis node, allowing mature grain to disperse freely. This phenotype is
referred to as ÔÔbrittle rachis.ÕÕ Classical genetic studies have established
that a mutation in either of two complementary and tightly linked genes on
barley chromosome 3HS, Non-brittle rachis 1 (btr1) or Non-brittle rachis 2 (btr2),
converts the brittle rachis into a non-brittle type. Pourkheirandish et al. (2015) identify Btr1 and Btr2 genes and elucidate the
mechanism underlying disarticulation of the wild-type barley spike. Independent
recessive mutations in each of these genes caused cell wall thickening in a
highly specific grain Ôdisarticulation zoneÕ, converting the brittle floral
axis (the rachis) of the wild-type into a tough, non-brittle form that promoted
grain retention.
The authors hypothize
that anthropogenic selection operated in favor of mutations in two adjacent
complementary dominant genes, the products of which are suggestive of a signal
transducing receptor and its protein ligand. The two genes products, BRT1 and
BRT2, act together to control the cell wall thickening in the disarticulation
zone of the rachis node through a molecular mechanism using comparative DNA
sequence information and archaeo botanical data. The authors demonstrated
independent origin of barley domestication. Two ÔÔtransition zonesÕÕ were
found, where major frequency changes between btr1- and btr2-types
occur: the region between Iran and Afghanistan and the Levant and the southern
part of the Mediterranean Sea. Besides these two transition zones, btr1-types were found to predominate in
India and Ethiopia. While possible that btr1-
and btr2-type barleys may be better
adapted to different eco-climatic zones, an alternative scenario is that their
current distribution is a direct result of human migration.
Figure 1 Spike of a barley plant derived from the small caryopsis Òseeded in hoodÓ.
It is evident the large size of the hood in which fertile organs are well
developed.
Figure 2 Reproductive organs in the Hood and developing grain ÒSeeded in HoodÓ
Laxatum (lax) and Cleistogami (cly1).
Reduction or increase of
the rachis internode length results in different spike density. Classical
genetic studies have identified several loci involved in modulation of spike
density, such as dense spike,
zeocriton and laxatum. Spike density
in barley is under the control of several major genes, as documented previously
by genetic analysis of a number of morphological mutants.
The
recessive mutation laxatum-a (lax-a)
in barley, which causes pleiotropic changes in spike development resulting in:
(i) extended rachis internodes conferring a more
relaxed (lax) inflorescence.
(ii) broadened base of the lemma awns.
(iii) thinner grains that are largely exposed due to
reduced marginal-growth of the palea and lemma.
(iv) and homeotic conversion of lodicules into two
stamenoid structures.
Map-based-cloning enforced by mapping-by-sequencing of
the mutant lax-a locus enabled the
identification of a homolog of BLADE-ON-PETIOLE1 and 2 (BOP1 and 2) as the
causal gene. Cloning of the laxatum-a
gene might open future perspectives in plant breeding, provide that adverse
phenotypic effects can be moderated or eliminated. Laxatum florets can open without impetus force of lodicules, which
were previously reported to be essential for open flowering in barley. Since
the wild-type structure of lemma and palea help keeping barley flowers closed during anthesis, the open flowering laxatum-a phenotype may help to achieve
open flowering independent of lodicules to facilitate hybrid breeding in barley.
Furthermore and similarly to the effect of the nud gene, the mostly hulless lax-a
seeds should be preferred for human food supply. The relaxed spike architecture
should be beneficial in humid growing conditions to unfavor fungal growth and
to achieve robust dry seeds for mechanical harvest. (Jost et al. 2016).
The closed floret habit (cleistogamy)
is under the control of cly1, a gene
that operates by inhibiting the development of the
lodicule. In non-cleistogamous cultivars, cly1
mRNA is degraded by miR172-directed cleavage, allowing the lodicules to swell; however, in cultivars carrying the recessive
allele cly1.b, a single-nucleotide
substitution destroys the miR172 target site preventing mRNA cleavage. Barley
cv. SV235 is cleistogamous; its cly1
coding sequence is identical to that of cly1.b,
but its lodicules develop, although insufficiently to produce a
non-cleistogamous flower. In this cultivar, the downregulation of cly1 is unrelated to
miR172-directed mRNA degradation, but rather caused by an epiallele that
represses transcription. Allelic relationships between known cly1 alleles were explored by the
quantification of lodicule vascularization and an assessment of the response of
the spike to the supply of exogenous auxin. The SV235 phenotype can be
manipulated by a pre-anthesis application of 2,4-D, a feature that could be of interest in the context of hybrid barley grain production based on
cleistogamy. The application of 2,4-D to spikes of cly1.b2 carriers induced floret gaping
and anther extrusion, thereby offering the possibility of manipulating flower
type by the simple expedient of spraying with 2,4-D. In the context of F1-hybrid
grain production, fully open flowering is necessary for both pollen dispersal
and cross-pollination. The cly1.b2
allele offers a practical means of controlling flowering type in F1-hybrids
involving two carriers of cly1.b2. A
2,4-D application supplied prior to anthesis should encourage the
non-cleistogamy needed for F1-hybrid grain production, while the F1-hybrid
plants themselves are cultivated normally and so remain cleistogamous. Closed
flowering is advantageous as it limits the entry of certain pathogens (in
particular Fusarium head blight fungus) and inhibits pollen-derived gene flow
(important in the context of genetically modified varieties). (Wang et al.2015).
Florigen is a systematic signal that is produced in
leaves in response to the stimulus of inductive day length and is transported
to the shoot apex to induce flowering. Li et
al. (2015) have studied the FLOWERING LOCUS T (FT) protein as central
component of a mobile flowering signal (florigen) that is transported from
leaves to the shoot apical meristem (SAM). Two FT monomers and two DNA-binding
bZIP transcription factors
interact with a dimeric 14-3-3 protein bridge to form a hexameric protein
complex. This complex, designated as the Ôflorigen activation complexÕ (FAC),
plays a critical role in flowering. The wheat homologue of FT, designated FT1
(= VRN3), activates expression of VRN1 in the leaves and the SAM,
promoting flowering under inductive long days. The authors show that FT1, other
FT-like proteins, and different FD-like proteins, can interact with multiple
wheat and barley 14-3-3 proteins, and they also identify the critical amino
acid residues in FT1 and FD-like proteins required for their interactions, and
demonstrate that 14-3-3 proteins are necessary bridges to mediate the
FT1–TaFDL2 interaction. Using in vivo bimolecular fluorescent
complementation (BiFC) assays, it has been demonstrated that the interaction
between FT1 and 14-3-3 occurs in the cytoplasm, and that this complex is then
translocated to the nucleus, where it interacts with TaFDL2 to form a FAC. In
addition the authors demonstrate that a FAC including FT1, TaFDL2 and Ta14-3-3C
can bind to the VRN1 promoter in vitro and finally, they show
that relative transcript levels of FD-like and 14-3-3 genes
vary among tissues and developmental stages. Since FD-like proteins determine
the DNA specificity of the FACs, variation in FD-like gene expression
can result in spatial and temporal modulation of the effects of mobile FT-like
signals.
Compositum Barley
Canonical barley spike has a branchless shape.
However, mutants characterized by branched spikes have been described as
naturally occurring since ancient times. Poly-row-and-branched spike (prbs)
mutation has been described as involved in the inflorescence differentiation
from a panicle into a spike. This mutation in fact can alter the inflorescence
morphology in two ways: a) determining the conversion of the rudimentary
lateral spikelets specific of two-rowed genotypes into fertile spikelets, b)
determining the development of additional spikelets in the middle of the spike,
resulting in a branched spike. In mutant prbs, new meristems initiated
at the flanks of lateral spikelets and middle spikelet meristems were converted
to branch meristems, developing branched spike. Prbs gene has been
mapped on chromosome 3H and demonstrated that this gene is not allelic to Vrs4. Vrs4 has been found involved even in another mutant phenotype
derived from a particular development of the node.
ÔCompositum-BarleyÕ and tetraploid
ÔMiracle-WheatÕ (T. Turgidum convar. compositum (L.f.) Filat.)
display non-canonical spike-branching in which spikelets are replaced by
lateral branch-like structures resembling small-sized secondary spikes. As a
result of this branch formation ÔMiracle-WheatÕ produces significantly
more grains per spike, leading to higher spike yield. Poursarebani et al.
(2015) investigated the genetic and molecular
basis of Òtrue spike-branchingÓ in ÔCompositum-BarleyÕ and tetraploid
ÔMiracle-WheatÕ
The gene com2 was positional cloned on
barley chromosome 2HS, and found that it is orthologous to bht that
regulates spike-branching in ÔMiracle-WheatÕ. Both genes possess
orthologs with similar functions in maize BRANCHED SILKLESS 1 [(BD1);
rice FRIZZY PANICLE/BRANCHED FLORETLESS 1 [(FZP/BFL1); and Brachypodium
distachyon MORE SPIKELETS 1 (MOS1)]. This candidate gene represents
a putative transcription factor consisting of a single exon, encoding a protein
of 307 amino acids containing an ethylene-responsive element DNA binding factor
(i.e. AP2/ERF). mRNA in situ hybridization, microarray experiments, and
independent qRT-PCR validation analyses revealed that the branch repression
pathway in barley is governed through the spike architecture gene Six-rowed
spike 4 regulating COM2 expression, while HvIDS1 (barley
ortholog of maize INDETERMINATE SPIKELET 1) is a putative
down-stream target of COM2. These findings provide new insights into the
genetic basis of spike architecture in Triticeae, and have disclosed new
targets for genetic manipulations aiming at boosting yield potential.
Liller et al.
(2015) recently evidenciated that mutation in barley row type genes have
pleiotropic effect on shoot branching. They suggest that
the same genes or regulatory modules can regulate both inflorescence branching
and tillering,
and they studied pleiotropic effects of row type genes on seed size,
seed number per spike, thousand grain weight and tillering in barley to better
understand the genetic correlations between individual yield components.
Allelic mutants of nine different row type loci (36 mutants), in the original
spring barley cultivars Barke, Bonus, Foma and introgressed in the spring
barley cultivar Bowman, were phenotyped under greenhouse and outdoor
conditions. Two main mutant groups were identified and characterized by their
relationships between seed and tillering parameters. The first group comprises
all mutants with an increased number of seeds and significant change in tiller
number at early development (group 1a) or reduced tillering only at full
maturity (group 1b). Mutants in the second group are characterized by a
reduction in seeds per spike and tiller number, thus exhibiting positive
correlations between seed and tiller number. Reduced tillering at full maturity
(group 1b) is likely due to resource limitations. In contrast, altered
tillering at early development (groups 1a and 2) suggests that the same genes
or regulatory modules affect inflorescence and shoot branching. Genes involved
in development of the branched inflorescence architecture of the grasses also control
seed size and shoot branching. These results indicate that correlations between
shoot and spike architecture are due to a)
competition between different sink organs for limited
assimilates or b) the direct involvement of row type genes in the initiation
and growth control of different plant organs, seeds and tillers. The authors
thus speculate that the same regulatory genes or modules may control the
development of different meristematic structures andorgans in plants.
Understanding how these genes are regulated and in turn control downstream
targets in different plant organs is important to improve yield by modifying
shoot and spike architecture. Understanding the genetic bases of the trade-offs
between these traits is important for the genetic manipulation of individual
yield components.
Double
Mutants
Double mutants Hv-Hd/tw2, formed
by hybridization, are characterized by inherited phenotypic instability and by
several new features, such as bract/leaf-like structures, long naked gaps in
the spike, and a wide spectrum of variations in the basic and ectopic flowers
which are absent in single mutants. Several of these features
resemble those of mutations in auxin distribution, and thus the aim of this
study was to determine whether auxin imbalances are related to phenotypic
variations and instability. The effects of auxin inhibitors and 2,4-D
(2,4-dichlorophenoxyacetic acid) on variation in basic and ectopic flowers were
therefore examined, together with the effects of 2,4-D on spike structure. The
occurrences of various malformations of spike structure, including
leaf/bract-like structures, also demonstrate the existence of other
developmental trends. Consequently, phenotypically unstable barley double
mutants are a highly promising genetic system for the investigation of gene
expression modules and trend rodersi. (Šiukšta et al. 2015)
The erectoides-m anthocyanin-less
1 (ert-m ant1) double mutants are among the very few
examples of induced double mutants in barley. From phenotypic observations of
mutant plants it is known that the Ert-m gene product
regulates plant architecture whereas the Ant1 gene product is involved
in anthocyanin biosynthesis. Zakhrabekova et
al. (2015) used a near-isogenic line of the cultivar Bowman, BW316 (ert-m.34),
to create four F2-mapping populations by crosses to the barley
cultivars Barke, Morex, Bowman and Quench. They phenotyped and genotyped 460
plants, allowing the ert-m mutation to be mapped to an
interval of 4.7 cM on the short arm of barley chromosome 7H. Bioinformatic
searches identified 21 candidate gene models in the mapped region. One gene was
orthologous to a regulator of Arabidopsis thaliana plant architecture,
ERECTA, encoding a leucine-rich repeat receptor-like kinase.
Sequencing of HvERECTA in barley, ert-m mutant
accessions identified severe DNA changes in 15 mutants, including full gene
deletions in ert-m.40 and ert-m.64. Both
deletions, additionally causing anthocyanin deficiency, were found to stretch
over a large region including two putative candidate genes for the anthocyanin
biosynthesis locus Ant1. Analyses of ert-m and ant1
single- and double-deletion mutants suggest Ant1 as a closely linked
gene encoding a R2R3 myeloblastosis transcription factor.
The mirEX 2.0
portal provides the plant research community with easily accessible data and
powerful tools for application in multi-conditioned analyses of miRNA expression
from important plant species in different biological and developmental
backgrounds. Zielenzinnski et al.
(2015) demonstrate that the mirEX 2.0 portal is dedicated to researchers
working on specific microRNA functions and expression profiles of entire microRNA
family members during a particular organ/developmental stage or on microRNA
biogenesis and evolution. The mirEX 2.0 web-based portal is a one-stop solution
for the exploration of plant microRNA expression data covering mutants and
three plant species representing scientifically (Arabidopsis thaliana),
economically (Hordeum vulgare), and evolutionarily (Pellia
endiviifolia) attractive research models. The provided user-friendly tools
allow to explore expression data in any combination of species, tissues and
developmental stages, thus leading to the rapid discovery and
hypothesis-building of underlying relations and regulatory mechanisms. The
developed technology also allows for unlimited further expansion of the data
content and provides an environment for the design of novel tools following the
needs of the plant community involved in the exploration of microRNA biology.
References:
Li C., Lin H., and Dubcovsky G. 2015. Factorial combinations of protein interactions
generate a multiplicity of florigen activation complexes in wheat and barley.
The Plant Journal 84, 70-82.
Lille Corinna Brit, RenŽ Neuhaus, Maria von Korff, Maarten Koornneef,
and Wilma van Esse. 2015. Mutations in Barley Row Type Genes Have Pleiotropic Effects on Shoot
Branching. PLOS ONE 1-20.
Pourkheirandish M., G. Hensel, B. Kilian, J. Kumlehn, K. Sato, and T.
Komatsuda. 2015. Evolution
of the Grain Dispersal System in Barley. Cell 162, 527–539.
Poursarebani N., T. Seidensticker, R. Koppolu, C. Trautewig, P.
Gawroński, F.Bini, G. Govind, T.Rutten, S. Sakuma, A. Tagiri, G.M.Wolde,
H.M. Youssef, A. Battal, S. Ciannamea, T. Fusca, T. Nussbaumer, C. Pozzi, A.
Bšrner, U. Lundqvist, T. Komatsuda, S. Salvi, R. Tuberosa, C. Uauy, N.
Sreenivasulu, L. Rossini, and T. Schnurbusch. 2015. The genetic basis of composite
spike form in barley and ÔMiracle-WheatÕ. Genetics 201:155-165.
Šiukšta Raimondas, Virginija Vaitkūnienė, Greta Kaselytė, Vaiva Okockytė, Justina Žukauskaitė, Donatas Žvingila, and Vytautas Rančelis. 2015. Inherited phenotype instability of
inflorescence and floral organ development in homeotic barley double mutants
and its specific modification by auxin inhibitors and 2,4-D . Annals of Botany
1-13.
Wang N., S. Ning, J. Wu, A. Tagiri, and T. Komatsuda. 2015. An Epiallele at cly1 Affects the
Expression of Floret Closing (Cleistogamy) in Barley. Genetics 199, 95-104.
mirEX: a platform for comparative
exploration of plant pri-miRNA expression data.
Zakhrabekova Shakhira, Christoph Dockter, Katharina Ahmann, Ilka
Braumann, Simon P Gough, Toni Wendt, Udda Lundqvist, Martin Mascher, Nils
Stein, and Mats Hansson. 2015. Genetic linkage facilitates cloning of Ert-m
regulating plant architecture in barley and identified a strong candidate of
Ant1 involved in anthocyanin biosynthesis. Plant Mol Biol 88:609-626.
Zielezinski, Andrzej, Jakub Dolata, Sylwia Alaba, Katarzyna Kruszka,
Andrzej Pacak, Aleksandra Swida-Barteczka, Katarzyna Knop, Agata Stepien, Dawid
Bielewicz, Halina Pietrykowska, Izabela Sierocka, Lukasz Sobkowiak, Alicja
Lakomiak, Artur Jarmolowski, Zofia Szweykowska-Kulinska, and Wojciech M
Karlowski. 2015. mirEX 2.0-an integrated environment for expression
profiling of plant microRNAs. BMC Plant Biology 15:144.
CoordinatorÕs report: Semidwarf genes
Jerry D. Franckowiak
Department of Agronomy and Plant Genetics
University of Minnesota Twin Cities
411 Borlaug Hall
1991 Upper Buford Circle
St Paul, MN 55108, USA
e-mail: jfrancko@umn.edu
Yield losses and quality
reductions caused by lodging are a frequent production problem in barley (Hordeum vulgare L.) Minimizing such
losses has been a goal of barley growers since the crop was domesticated. The
strategy most frequently employed to minimize losses is a genetic reduction of
plant height. However, lodging is a complex trait in which can be expressed
from around heading time until harvest. Lodging about heading is often the most
frequent cause of losses, but post-ripe straw breakage or crinkling of straw
prior to mechanical harvest causes losses also.
Plant height genes - Mutant genes that reduced plant
height or elongation of culm internodes are often the focus of breeding
efforts. The most commonly used genes for height reduction in barley have
involved specific alleles at three loci: the uzu1.a allele at the uzu 1 locus, the sdw1.c (denso) allele at the semidwarf 1 locus, and ari-e.GP (Golden Promise) allele at the
breviaristatum-e locus. The uzu1.a
gene was widely used in winter barleys developed in East Asia (Chono et al., 2003; Dockter et al., 2014). The sdw1.c gene has been widely deployed in Europe and is used in some
other barley growing regions of the world (Jia et al., 2011; Malosetti et al.,
2011). The ari-e.GP has been used to
a limited extent in England and Australia (Ellis et al., 2002; Malosetti et al., 2011; Walia et al., 2007). More recently the sdw4.ad allele at the semidwarf 4 locus has found favor in winter
grown spring barley cultivars developed for China and Japan (Sameri et al., 2009; Yu et al., 2010). Despite their favorable effects on plant height,
worldwide deployment of these semi-dwarfing genes in barley improvement is
restricted because their origin in genetic background poorly adapted to the
target production area and the semidwarf genes have pleiotropic effects on
other agronomic characteristics. Most notable are the sensitivity of the uzu1.a mutant to high temperatures
(Dockter et al., 2014) and delayed
maturity associated with sdw1.c and
other mutants at that locus (Jia et al.,
2011).
Haploblock identification - The characterized
semidwarf genes do not explain all the observed variation in plant height
(Pasum et al., 2012). The advent of
relatively dense molecular maps for barley has facilitated further dissection
of qualitative trait loci (QTL) associated with specific traits. Using identity
by descent and allele associated haplotypes, or preferably a haploblock of
adjacent molecular markers, presence or absence of specific height genes can be
determined in breeding materials and historic cultivars. Using procedures for
DArTseq marker identification (Diversity Arrays Technology, Yarralumla, ACT 2600,
Australia; http://www.diversityarrays.com),
over 10,000 polymorphic SNP markers with assigned chromosomal positions were
characterized for an array of Australian breeding lines, cultivars,
and historic accessions (Wang et al.,
2015). Visual realignment of markers based on breakpoints in a doubled-haploid
population (NRB091087/NRB091047) and closely related breeding lines increased
the number of positioned markers to over 17,000. The relative positions of the
realigned markers were used to identify haploblocks associated with specific
plant height genes (Table 1).
Additional plant height genes – Haploblocks
associated with semidwarf genes should be present in short stature breeding
lines; however, this association was not observed in all Australian semidwarf
cultivars. Likewise in a worldwide collection of barley cultivars, Pasum et al.
(2012) reported that QTL distributed across the barley genome are associated
with variation in plant height. Hence, additional semidwarf loci may exit in
cultivated barley. One candidate group is the semidwarf accessions that
originated from the International Center for
Agricultural Research in the Dry Areas (ICARDA) barley breeding program
at the International Maize and Wheat Improvement Center (CIMMYT) in Mexico.
Negeri (2009) identified a plant height QTL in the short arm of chromosome 6H
in the Chinese cultivar Shenmai
3 (Gobernadora/Humai 10), which was selected at CIMMYT from a cross to
Gobernadora (OC640/Mari//Pioneer/3/Maris Concord). A unique haploblock was
found in 6HS in Canela (Maris Canon/Laurel//Aleli) and several other ICARDA
lines from Mexico (Table 1). This haploblock is near the 6HS position was
identified by Pasum et al. (2012) as
having a large effect on plant height. The recommended locus symbol for this
QTL is sdw5 and the recommended
allele symbol is sdw5.be. The
haploblock associated with the sdw5.be
allele is present in several Australian cultivars. These include Commander
(Keel/Sloop//Galaxy) and Keel (CPI18197/Clipper//WI2645).
The semidwarf genes are
considered here because their deployment of various combinations can further
reduce plant height and may reduce losses caused by lodging. The presence of
various haploblocks associated with plant height genes suggests that several
Australian cultivars already have two or more semidwarf genes. Hindmarsh
(Chariot/VB9409) has the haploblocks associated with the ari-e.GP and sdw1.c
genes. Commander has the haploblocks associated with sdw1.c and sdw5.be. Since
other relatively short stature cultivars have one or no identified semidwarf
gene, additional semidwarf genes in cultivated barley are still to be
identified.
References:
Chono, M., I. Honda, H.
Zeniya, K. Yoneyama, D. Saisho, K. Takeda, S. Takatsuto, T. Hoshino, and Y.
Watanabe. 2003. A semidwarf phenotype of barley uzu
results from a nucleotide substitution in the gene encoding a putative
brassinosteroid receptor. Plant Physiol. 133:1209-1219.
Dockter, C., D. Gruszka,
I. Braumann, A. Druka, I. Druka, J. Franckowiak, S. P. Gough, A. Janeczko, M.
Kurowska, J. Lundqvist, U. Lundqvist, M. Marzec, I. Matyszczak, A. H. MŸller,
J. Oklestkova, B. Schulz, S. Zakhrabekova, and M. Hansson. 2014.
Induced variations in brassinosteroid genes define barley height and
sturdiness, and expand the green revolution genetic toolkit. Plant Physiol. 166:1912-1927.
Ellis, R.P, B.P. Forster, D.C. Gordon, L.L. Handley, R.P. Keith, P.
Lawrence, R. Meyer, W. Powell, D. Robinson,
C.M. Scrimgeour, G. Young, and W.T.B. Thomas. 2002. Phenotype/genotype
associations for yield and salt tolerance in a barley mapping population
segregating for two dwarfing genes. J. Exp. Bot.
53:1163-1176.
Jia, Q., X.Q. Zhang, S. Westcott, S.
Broughton, M. Cakir, J. Yang, R. Lance, and C. Li. 2011.
Expression level of a gibberellin 20-oxidase gene is associated with multiple
agronomic and quality traits in barley. Theor. Appl. Genet. 122:1451-1460.
Malosetti, M., F.A. van Eeuwijk,
M.P. Boer, A.M. Casas, M. El’a, M. Moralejo, P.R. Bhat, L. Ramsay, and J.-L.
Molina-Cano. 2011. Gene and QTL detection in a three-way barley cross
under selection by a mixed model with kinship information using SNPs. Theor.
Appl. Genet. 122:1605-1616.
Negeri,
A.T. 2009. Genetic mapping of QTL for FHB resistance and whole
genome association mapping in barley. Ph.D. Thesis, North Dakota State
University, Fargo, ND, USA.
Pasam, R.K., R. Sharma,
M. Malosetti, F.A. van Eeuwijk, G. Haseneyer, B. Kilian, and A. Graner. 2012. Genome-wide association studies for agronomical traits in a world-wide
spring barley collection. BMC Plant Biol. 12:16.
Sameri,
M., S. Nakamura, S.K. Nair, K. Takeda, and T. Komatsuda. 2009. A quantitative trait locus for reduced culm
internode length in barley segregates as a Mendelian gene. Theor. Appl. Genet.
118:643-652.
Walia, H., C. Wilson, P. Condamine,
A.M. Ismail, J. Xu, X. Cui, and T.J. Close. 2007. Array-based genotyping and
expression analysis of barley cv. Maythorpe and Golden Promise. BMC Genomics. 2007; 8:87.
Wang,
X., E.S. Mace, G.J. Platz, C.H. Hunt, L.T. Hickey, J.D. Franckowiak, and D.R.
Jordan. 2015.
Spot form of net blotch resistance in barley is under complex genetic control.
Theor. Appl. Genet. 128:489-499.
Yu,
G.T., R.D. Horsley, B. Zhang, and J.D. Franckowiak. 2010. A new semi-dwarfing gene identified by molecular
mapping of quantitative trait loci in barley. Theor. Appl. Genet. 120:853-861.
|
Table 1. A
partial list of plant height genes involved in adaptation of barley to
specific production areas including origin, chromosomal position, and
phenotypic effects. |
|||||||||
|
Locus name |
Chromosome position |
|
DArTseq
marker / phase |
Marker
position |
Gene
or mutant source |
Probable
trait origin |
Notes |
||
|
Plant height genes |
|
|
|
|
|
|
|||
|
sdw1.c
(denso) |
Semidwarf
1 |
3H
bin12 |
3264976 - |
124.00 |
Abed
Denso |
Europe |
Reduced height, delayed heading and smaller kernels |
||
|
|
|
|
3663177 - |
|
Triumph |
|
|
||
|
|
|
|
3397429 + |
|
|
|
|
||
|
sdw4.ba |
Semidwarf
4 |
7H
bin11 |
3661780 - |
118.24 |
Zhenongda
7 |
China |
China / Japan semidwarf, short basal culm internodes |
||
|
|
|
|
3265446 + |
|
|
|
|
||
|
|
|
|
3396373 - |
|
|
|
|
||
Table 1 continued
|
sdw5.be
(q6HT4) |
Semidwarf
5 |
6H
bin05 |
3985790 + |
35.98 |
Canela |
Mexico |
Semidwarf gene in CIMMYT-ICARDA cultivars |
||
|
|
|
|
4189414 + |
|
Keel |
Australia |
|
||
|
|
|
|
3931643 + |
|
|
|
|
||
|
ari-e.GP |
Breviaristatum-e |
5H
bin06 |
4186599 + |
50.00 |
Golden
Promise |
England |
Short awned semidwarf mutant from Maythorpe |
||
|
|
|
|
3273517 + |
|
|
|
|
||
|
|
|
|
3273238 + |
|
|
|
|
||
|
uzu1.a
(HvBRI1) |
Uzu 1 |
3H
bin06 |
Gene
not present |
|
Winter
six-rowed |
China |
Degree of dwarfing is temperature sensitive, short awns |
||
|
|
|
|
|
|
|
|
|
||
Faculty of Agriculture, Food & Wine
The University of Adelaide, Waite Campus,
Glen Osmond, SA 5064, Australia
e-mail: akm.islam@adelaide.edu.au
It has been possible to
produce five disomic addition lines (2H,3H,4H,6H,7H) of six-rowed Ukrainian
winter barley cultivar ÔManasÕ to ÔAsakaziÕ wheat ( Marta Molnar- Lang et al
2012). Furthermore, new wheat x barley
hybrids (wheat Mr9kr1 x barley Igri; wheat Mr9kr1 x barley Betzes; wheat
Asakaze komugi x barley Manas have been produced by (M.Molnar-Lang et al 2000,
E.Szakacs et al 2007, I. Molnar et al 2007) Partial sets of addition,
substitution and translocation lines were then developed from these hybrids. Tatyana et al (2013) reported the
production of ditelosomic 7HL(7D) and monotelosomic 7HL(7A) and 7HL(7B)
substitution lines of Hordeum marinum ssp
gassoneanum to common wheat cv. Saratovskaya.
References:
Efremova, T., A. Valentina, N.
Trubacheeva, T. Ocadchaya, E. Chumanova, and L. Pershina. 2012.
Substitution of Hordeum marinum ssp. Gassoneanum chromosome 7HL into wheat
homoeologous group-7. Euphytica, Vol.192 No.2, pp. 251-257.
Molnar. I., G. Linc, S. Dulai, E.D.
Nagy, and M. Molnar-Lang. 2007. Ability of Chromosome
4H to Compensate for 4D in Response to Drought Stress in a Newly Developed and
Identified Wheat-Barley 4H (4D) Disomic Substitution Line. Plant Breeding, Vol.
126, No. 4, pp. 369-374.
Molnar-Lang, M., G. Linc, A.
Logojan, and J. Sutka. 2000. Production and Meiotic
Pairing Behaviour of New Hybrids of Winter Wheat (Triticum aestivum) x Winter Barley (Hordum vulgare). Genome, Vol. 43, No. 6, pp, 1045-1054.
Molnar-Lang, M., K. Kruppa, A. Cseh,
J. Bucsi, and G. Linc. 2012. Identification and phenotypic
description of new wheat-six-rowed winter barley disomic additions. Genome 55,
Vol.4, pp. 302-311.
Szakas,E. and M. Molnar-Lang. 2007.
Development and Molecular Cytogenetic Identification of New Winter Wheat/Winter
Barley (Martonvasari 9 kr1/Igri) Disomic Addition Lines. Genome, Vol. 50, No. 1,
pp. 43-50.