JOHN INNES CENTRE
Cereals Research Department, Norwich Research Park, Colney, Norwich NR4 7UH,
United Kingdom
A cereal centromeric sequence.
L. Aragon-Alcaide, T.E. Miller, T. Schwarzacher,
and S.M. Reader.
A family of sequences (CCS1, cereal centromere sequence
1) was identified by in situ hybridization to be present in all
Triticeae species including supernummary at midget chromosomes.
The sequence also is found in the centromeres of all maize chromosomes
and the heterochromatic regions of rice chromosomes. CCS1, together
with the cereal genome alignments, will allow the evolution of
the cereal centromeres and their sites to be studied. The family
of sequences also shows some homology to the CENP-B box of
human centromeric oa-satellite DNA.
The importance of centromeres in chromosome recognition prior to synapsis.
L. Aragon-Alcaide, S.M. Reader, T.E. Miller, and G. Moore.
Understanding the mechanisms of action of genes controlling chromosome pairing such as Ph1, Ph2, and pairing the promotor gene/s of Ae. speltoides is important. All these genes are likely to act through a common mechanism at their chromosomal sites of action, whether these are centromeric, telomeric, or interstitial. Using 3-dimensional confocal microscopy on meiotic anther sections, we have demonstrated that homologous chromosomes first come in contact at their centromeric sites prior to leptotene, and is probably followed by interstitial sites along the arms. Finally, at early leptotene, all the telomeres aggregate in a particular area of the nuclear envelope forming the `bouquet' configuration. These data establish a clear difference between homologous chromosome recognition (mediated by centromeres and other interstitial sites) and synapsis of homologues (mediated by the telomeres). We also have demonstrated that Ph1, Ph2, and the pairing genes of Ae. speltoides have a common mode-of-action at the centromeres. Decondensation and condensation of centromeres was studied in nine different pairing conditions and correlated with homoeologous and homologous chromosome pairing. This mechanism also could be active at other interstitial recognition sites. However, such sites may be difficult to follow. The results also support the crucial role of centromeres in chromosome recognition. This important role is perhaps reflected in the strong conservation of centromere sequences in genomes of barley, wheat, rye, maize, and rice and in the neocentromeric sites of maize chromosomes. We have shown that centromeric sites map at the border sites between the conserved linkage blocks in the cereal genomes, implying that these sites are points of breakage and fusion during evolution. The use of synteny will enable rice to be used to clone the Ph1 gene of wheat, as we have contiged the Ph1 deletion using rice YACs. We are now in a position to both clone the gene and understand its mechanism of action via its interaction with centromeric sequences.
The influence of photoperiod genes on the adaptability of
European winter wheats.
A.J. Worland, A. Börner,
(IPK, Gatersleben, Germany), and S. Petrovic (Institute of Field
and Vegetable Crops, Novi Sad, Serbia).
The climatic adaptability of European winter wheat
cultivars is determined to a major extent by genes controlling
photoperiod response. The vast majority of photoperiod-insensitive
European wheat cultivars probably have their insensitivity determined
by the Ppd1 allele, originally derived from the old Japanese
variety Akakomugi. This gene was introduced into European cultivars
by the Italian breeder Strampelli.
Pleiotropic effects of the Akakomugi Ppd1
gene were evaluated over a l0-year period in the U.K. using single-chromosome
recombinant lines developed in a Cappelle-Desprez background
by recombining the 2D chromosomes of Cappelle-Desprez and
the Italian Akakomugi-derived cultivar Mara. The results show
Ppd1 significantly accelerates ear emergence time but reduces
tillering height and spikelet numbers. Increases in spikelet
fertility more than compensate for reduced spikelet numbers, resulting
in an overall increase in numbers of grains per ear. Final plant
yield is very dependent on climatic conditions prevailing after
seed set. In a typical cool damp U.K. summer, later-flowering
photoperiod-sensitive lines with a longer spike and fewer grains
per spikelet benefit from the ideal grain filling conditions and
produce the highest yields. In light of recent warmer, drier
summers, even in the U.K., earlier-flowering photoperiod-insensitive
lines produce yield advantages of up to 90 %.
Similar experiments were grown in Serbia and at Gatersleben,
in central Germany. In Serbia, with its regular hot, dry summers,
Ppd1 produces an annual yield advantage of at least 30 %.
In Germany, most seasons show the earlier-flowering lines producing
higher yields, averaging 7.7 % for the period l989-96.
In recent seasons, the Ppd1 allele from the
CIMMYT cultivar Ciano 67 has been compared to that from Mara.
Results indicate that although the complete substituted 2D chromosomes
of Ciano 67 or Mara in similar genetic backgrounds show differences
in flowering time and spikelet fertility, when the Ppd
effects are separated out in single-chromosome recombinant lines,
there is no evidence to suggest allelic differences at the Ppd1
locus.
The weaker photoperiod gene Ppd2 from Chinese
Spring also has been evaluated over the past 3 years. Results
show that Ppd2 exerts similar but less pronounced effects
to Ppd1, accelerating flowering time by approximately 4
days with pleiotropic effects that reduce height and tiller and
spikelet numbers but increase spikelet fertility. In each of
the 3-year trials in the U.K., Ppd2 increased yield by
6 % more than Ppd1.
Results of the 10-year trials of photoperiod genes
indicate that in southern Europe, photoperiod insensitivity has
a clear adaptive significance. In northern Europe, sensitivity
has a similar adaptive significance. However, a broad area exists
through central Europe where annual climatic variations make it
extremely difficult for breeders to produce cultivars with good
adaptability to changing environmental conditions.
Genes and markers for resistance to preharvest sprouting.
J.E. Flintham, R.E.A. Adlam, P. Bailey, and M.D. Gale.
Following the identification of the barley cDNAs BCD131 and ABC174 as flanking markers for the R (red grain color) genes in wheat, genome-specific clones obtained by nullisomic-tetrasomic PCR were sequenced as tags for the loci on chromosomes 3A, 3B, and 3D. In collaboration with IACR, Long Ashton, U.K., wheat homologues of the maize Vp1 (vivpary) gene were cloned and are being used to test the predicted coincidence of the Vp1 and R loci. A single, major gene controlling seed dormancy has been detected in doubled haploids from a cross between two R1 R2 R3 wheats, which operates via the embryo genotype rather than via the seed coat. AFLP and SSR are being used to assign a map location for this new dormancy gene.
Development of a genome-based protocol for monitoring pasta
adulteration.
P. Stephenson, J. Kirby, G.J. Bryan (now at SCRI, Invergowrie, U.K.) and G. Wiseman (RHM Technology Ltd., High Wycombe, U.K.).
The majority of pastas that are manufactured and
offered for sale within the European community are made solely
from durum wheat semolina and are considered to be superior products
to those manufactured from common wheat or mixtures of the two.
Several European countries including Italy, Spain, and France
view the inclusion of common wheat in pasta as adulteration.
The U.K. does not currently have specific regulations regarding
the composition of pasta. However, both the Food Safety Act of
1990 and the Food Labeling Regulations of 1984 make it clear that
it is an offence to mislabel a product. Hence, the presence of
common wheat in a pasta product must be declared.
A number of different analytical methods currently
are available that rely upon detecting the products of the D genome,
which is present in hexaploid, but not tetraploid wheat. These
methods usually involve the extraction of soluble proteins and
analysis by IEF or PAGE. The principal limitation of these methods
is protein denaturation during the manufacturing process. Detecting
and quantifying T. aestivum contamination in T. durum
pastas at the genomic level seems logical. We have developed
a method for the detection of D-genome sequences in DNA extracted
from pasta.
Under industrial conditions, a series of control
pastas was made containing precise levels of T. aestivum
adulteration covering the range of adulteration levels causing
most concern both to industry and the regulatory bodies. These
were manufactured using three different drying regimes (56, 80,
and 104 C)
representing the range of drying protocols widely used by industry.
DNA was extracted successfully from both store-bought and control
pasta samples using traditional extraction procedures and the
more automated resin-based systems. The isolated genomic DNA,
although degraded, is suitable for PCR analysis. Repetitive sequences
thought to be D-genome specific were investigated. A 2.2 kb DNA
sequence (Dgas44) was extensively investigated, and although not
all the primers examined were D-genome specific, primers were
designed that amplify only from the D genome. The D genome of
the adulterating T. aestivum was readily detected in all
adulterated pastas using primers to specific regions of the Dgass44
sequence down to the 1 % level. This procedure currently is being
developed for use with the fluorescent primer/probe system developed
by Perkin-Elmer (TaqMan) to provide a fast, accurate, and
reliable service to the food industry and its regulatory bodies.
Physical mapping of NOR sites in the M genome of Ae. comosa.
Y.J. Park, T.E. Miller, and S.M. Reader.
rDNA sequences are highly conserved across genomes
and are located in the NORs of chromosomes. Members of the tribe
Triticeae have one or two major NORs located on the chromosomes
of homoeologous groups, 1, 5, or 6, and minor loci also are known
to be present on other chromosomes.
Most diploid species of the genus Aegilops
have one NOR site on their group 1 and 5 chromosomes. Fluorescent
in situ hybridization was used to construct a physical map of
the NOR sites on the chromosomes of Ae. comosa, using the
DNA sequence pTa71 (containing wheat 18S-5.8S-26S
rDNA) as a probe.
Major sites were located on chromosomes 1M and 6M.
Additional minor sites also were detected in the subtelomeric
regions of the short arms of chromosomes 2M, 3M, and 5M. Thus,
Ae. comosa differs from other Aegilops species in
the number and location of its NOR sites.
Characterization of the chromosomes of Dasypyrum villosum
by fluorescent in situ hybridization.
E. Uslu, S.M. Reader, K.A. Cant, and T.E. Miller.
Fluorescent in situ hybridization was performed on
E.R. Sear's disomic wheat-D.
villosum chromosome addition lines in
order to characterize the V-genome chromosomes of D. villosum.
The V-genome specific DNA sequence pHv62, the rye sequence
pSc119.2, the 18S-25S
rDNA sequence from wheat, and the 5S rDNA sequence from pea were
used as probes. The pHv62 probe also was hybridized to a number
of other Triticeae species and has been shown to hybridize
to four pairs of Th. bessarabicum chromosomes and also
weakly to rye, S. cereale, chromosomes. The probe does
not hybridize to wheat or to a range of Aegilops species.
pHv62 hybridizes subtelomerically to each arm of
chromosomes 1V, 2V, 4V, and 6V, but only one arm of 5V and does
not hybridize to either arm of 7V. Minor pericentric sites were
also detected on 1V, 2V, 4V, 5V, and 6V. The hybridization pattern
of 3V has not been categorically confirmed. To date, the 3V addition
line has failed to show any hybridization with any RFLP marker,
group 3 or otherwise, so its validity remains to be confirmed.
pSc119.2 hybridized close to the telomeres of all seven V-genome
chromosomes. Chromosome 1V has an 18S-5.8S-26S
rDNA site on its short arm. A single 5S rDNA site is located
distally on the short arm of chromosome 5V.
Publications.
Anamthwat-Jonsson
K, Heslop-Harrison JS, Schwarzacher T. 1996. Genomic in
situ hybridization for whole chromosome and genome analysis.
In: In Situ Hybridization: A Laboratory Companion
(Clark M ed). London, Chapman & Hall. pp. 1-22.
Aragon-Alcaide
L, Miller TE, Schwarzacher T, Reader S, and Moore G. 1996. A
cereal centromeric sequence. Chromosoma 105:261-268.
Ben Amer IM, Worland AJ, and Börner
A. 1996. The effects of whole chromosome substitutions differing
in alleles for hybrid dwarfing and photoperiodic sensitivity on
tissue culture response in wheat. Euphytica 89:81-86.
Bimb HR. 1996. Genetics of resistance to yellow
rust in bread wheats derived from CIMMYT and other sources. Ph.D.
Thesis, University of East Anglia.
Börner
A, Plasche J, Korzun V, and Worland AJ. 1996. The relationship
between the dwarfing genes of wheat and rye. Euphytica 89:69-75.
Calonnec A. 1996. Genetic analysis of differential
varieties of wheat used to characterise races of Puccinia striiformis,
the cause of yellow rust. Ph.D. Thesis, Universitae
de Paris-Sud, U.F.R. Scietific D'Orsay.
Castilho A and Heslop-Harrison JS. 1996. Characterization
of wheat-Aegilops umbellulata recombinant lines by
in situ hybridization. In: Proc 2nd Inter Triticeae
Conf (Wang RRC and Jensen KB eds). Logan, Utah, Utah State University.
pp. 150-154.
Castilho A, Miller TE, and Helsop-Harrison JS.
1996. Physical mapping of translocation breakpoints in a set
of wheat Aegilops umbellulata recombinant lines using in
situ hybridization. Theor Appl Genet 93:8l6-825.
Collins S, Fernandez-Lobato M, Gooding PS, Mullineaux PM, and Fenoll C. 1996. The two nonstructural proteins from wheat dwarf virus involved in viral gene expression and replication are retinoblastoma-binding proteins. Virology 219:324-329.
Dolinski R, Miazga D, Worland A, and Kowalczyk K.
1996. Genetic analysis of selected physical properties of the
culm of Cappelle-Desprez/Bezostya substitution lines. Acta
Agronomica Hungarica 44:245-254.
Dyer PS, Nicholson P, Lucas JA, and Peberdy JF.
1996. Tapesia acuformis as a causal agent of eyespot disease
of cereals and evidence for a heterothallic mating system using
molecular markers. Mycol Res 100:1219-1226.
Flavell RB and Moore G. 1996. Plant genome constituents
and their organisation. In: Plant Gene Isolation (Foster
GD and Twell D eds). New York, Wiley & Sons. pp. 1-25.
Gustafson JP and Snape JW. 1996. Gene manipulation
in wheat improvement. In: Plant Chromosomes: Laboratory Methods
(Fukui K and Hakayama S eds) Boca Raton, CRC Press. pp. 205-218.
Hagelin K, Rodriguez-Suarez R, Katzen F, Wolosiuk
RA, Baldi PC, Guiambartolomei GH, Fossati CA, and Dyer TA. 1996.
Interspecies cross-reactivity of a monoclonal antibody directed
against wheat chloroplast fructose-1,6-bisphosphatase.
Cell Mol Biol 42:673- 682.
Hague RE and Brown JKM. 1996. Molecular and biometrical
genetics of powdery mildew resistance in wheat. Proc 9th Eur
and Mediter Cereal Rusts and Powdery Mildews Conf, Lunteren, The
Netherlands. pp. 204-207.
Islam-Faridi MN, Worland AJ, and Law CN. 1996.
Inhibition of ear-ermergence time and sensitivity to day-length
determined by the group 6 chromosomes of wheat. Heredity 77:572-580.
Jia J, Devos KM, Chao S, Miller TE, Reader SM, and
Gale MD. 1996. RFLP-based maps of the homoeologous group-6
chromosomes of wheat and their application in the tagging of Pm12,
a powdery mildew resistance gene transferred from Aegilops
speltoides to wheat. Theor Appl Genet 92:559-565.
Johnson R and Bimb HP. 1996. Genetics of resistance
to yellow rust in CIMMYT wheats. Proc 9th Eur and Mediter Cereal
Rusts and Powdery Mildews Conference, Lunteren, The Netherlands.
pp. 195-197.
King IP, Cant KA, Law CN, Worland AJ, Orford SE,
Reader SM, and Miller TE. 1996. An assessment of the potential
of 4DS-4DL-Sl
translocation lines as a means of eliminating tall off types in
semi-dwarf wheat varieties. Euphytica 89:103-106.
King IP, Orford SE, Cant KA, Reader SM, and Miller
TE. 1996. An assessment of the salt tolerance of wheat/Thinopyrum
bessarabicum 5Eb addition and substitution lines.
Plant Breed 115:81-84.
Kosina R and Heslop-Harrison JS. 1996. Molecular
cytogenetics of an amphiploid trigeneric hybrid between Triticum
durum, Thinopyrum distichum and Lophopyrum elongatum.
Ann Bot 78:583-589.
Krattiger AF, Payne PI, Law CN. 1996. Effects of
homoeologous group 1 and 6 chromosomes of the Cappelle-Desprez
(Bezostaya 1) substitution lines on aspects of bread-making
quality of wheat. Euphytica 89:17-25.
Law CN and Worland AJ. 1996. Intervarietal chromosome
substitution lines in wheat revisited. Euphytica 89 1-10.
Lima-Brito J, Guedes-Pinto H, Harrison
GE, and Heslop-Harrison JS. 1996. Chromosome identification
and nuclear architecture in Triticale x Tritoredeum F1
hybrids. J Organometallic Chem 500:2l9-225.
Miller TE, Reader SM, Purdie KA, and King IP. 1996.
Fluorescent in situ hybridisation - a useful aid
to the introduction of alien genetic variation into wheat. Euphytica
89:113-119.
Money T, Reader S, Qu LJ, Dunford RP, and Moore G.
1996. AFLP-based mRNA fingerprinting. Nuc Acids Res 24:1616-1617.
Moot DJ, Jamieson PD, Henderson AL, Ford MA, and
Porter JR. 1996. Rate of change in harvest index during grain-filling
of wheat. J Agric Sci 126:387-395.
Nicholson P, Lees AK, Maurin N, Parry DW, and Rezanoor
HN. 1996. Development of a PCR assay to identify and quantify
Microdochium nivale var. nivale and Microdochium
nivale var. majus in wheat. Physiol Mol Plant Path
48:257-271.
Nicholson P and Parry DW. 1996. Development and
use of a PCR assay to detect Rhizoctonia cerealis, the
cause of sharp eyespot in wheat. Plant Path 45:872-883.
O'Hara RB. 1996. Population dynamics of cereal
powdery mildews. Ph.D. Thesis, University of East Anglia, U.K.
O'Hara RB and Brown JKM. 1996. Frequency and density
dependent selection in wheat powdery mildew. Heredity 77:439-447.
Parry DW and Nicholson P. 1996. Development of
a PCR assay to detect Fusarium poae in wheat. Plant Path
45:383-391.
Quarrie SA, Heyl A, Steed A, Lebreton C, and Lazic-Jancic
V. 1996. QTL analysis of stress responses as a method to study
the importance of stress-induced genes. In: Physical
Stresses in Plants, Genes and their Products for Tolerance (Grillo
S and Leone A eds). Proc ESF Workshop, Berlin. Springer. pp.
141-152
Rubiales D, Snijders CHA, Nicholson P, and Martin
A. 1996. Reaction of tritordeum to Fusarium culmorum and
Septoria nordorum. Euphytica 88:165-174.
Sardana RK and Flavell RB. 1996. Molecular cloning
and characterization of an unusually large intergenic spacer from
the Nor-B2 locus of hexaploid wheat. Genome 39:288-292.
Schwarzacher T. 1996. The physical organization
of Triticeae chromosomes. In: Unifying Plant Genomes:
Comparisons, Conservation and Collinearity. 50th SEB Symp (Heslop-Harrison
JS ed) Cambridge, Company of Biologists. pp. 71-75.
Snape JW, Laurie EDA, and Quarrie SA. 1996. Comparative
genetic analysis of stress responses in cereals. Proc 2nd FAPO/IAEA
Workshop on Radiation Induced Mutations and other Advanced Technologies
for the Production of Seed Crop Mutants Suitable for Environmentally
Sustainable Agriculture.
Snape JW, Quarrie SA, and Laurie DA. 1996. Comparative
mapping and its use for the genetic analysis of agronomic characters
in wheat. Euphytica 89:27-31.
Vershinin AV, Alkhimova EG, and Heslop-Harrison
JS. 1996. Molecular diversification of tandemly organized DNA
sequences and heterochromatic chromosome regions in some Triticeae
species. Chromosome Res 4:5l7-525.
Wang YB, Hu H, and Snape JW. 1996. The genetic
and molecular characterization of pollen-derived plant lines
from octoploid triticale x wheat hybrids. Theor Appl Genet
92:811-816.
Worland AJ. 1996. The influence of flowering time genes in environmental adaptability in European wheats. Euphytica 89:49-57. go to next document