II. 22. Variability of electrophoretic subunit patterns of seed hordeins in barley, Hordeum vulgare.
A. Kapala, Polish Academy of Sciences, Poznan, Poland.
Previous studies (Kapala, 1979; Kapala et al., 1975; Przybylska and Kapala, 1974) revealed differences between cultivated varieties and primitive forms of barley in the composition of salt-soluble seed proteins. Moreover, the high-lysine variety Hiproly distinguished by the specific, electrophoretic pattern of these proteins. The purpose of the present studies was to supply information on differences in the subunit composition of seed hordeins in spring barley (Hordeum vulgare). Significant variation in the subunit composition of seed hordeins of barley cultivars was already displayed by Shewry et al. (1978a, 1978b). In the present studies the analyzed barleys represented a wide scale of genetic and geographic variability. The materials covered cultivated varieties and breeding lines of European origin, naked and dark-hulled collection forms from Asia and Africa and well-known high-lysine forms; totally 50 forms were analyzed.
Hordeins were extracted with 65% ethanol (Lauriere and Mossee, 1977), treated with sodium dodecyl sulphate (SDS) - urea - 2-mercaptoethanol and electrophorized in SDS 12.5% polyacrylamide slab gels (Shewry et al., 1977).
Subunit patterns of the hordeins seemed to be genetically controlled features, not affected by environmental conditions during plant growth.
SDS-electrophoretic patterns of hordeins displayed three groups of bands described here as "A", "B" and "C" hordeins, with progressively higher molecular weight (Figure 1). The nomenclature of the hordein bands follows Køie et al. (1976). Apparent molecular weights were as follows: "A", MW -14,000 - 22,000; "B", MW -- 28,000 - 49,000; and "C", MW -- 50,000 - 85,000. All analyzed barley forms had similar hordein pattern of the "A" region; only high-lysine forms demonstrated stronger intensity of bands of this region. Investigated barleys differed in two groups of hordeins - "B" and "C". The specific subunit patterns for individual forms or form groups of barley were observed. The total number of major and minor components of hordeins varied from 8 to 18 in different forms of barley. Within all the analyzed barley forms, 21 types of polypeptide patterns were recorded (Figure 1 and Table 1).
Table 1. Polypeptide spectra of the hordeins of analyzed barley forms
The total number of major and minor components of hordeins varied from 10 to 14 within cultivated varieties and breeding lines (23 forms); there were eight types of polypeptide patterns. Only five varieties have distinctive patterns, whereas the others fall into groups of two, five and eleven varieties. The reported data agree in general with the results obtained by Shewry et al., (1978a, 1978b).
Regarding subunit patterns of hordeins of the collection forms (20 forms), the total number of components varied from 9 to 15, eight types of banding patterns being recorded. Generally, collection forms were observed to be more variable in respect of polypeptide patterns than cultivated varieties.
High-lysine forms demonstrated the strongest variability with respect to subunit patterns of hordeins. Seven high-lysine barleys demonstrated five types of polypeptide spectrum. KVL system 16 and KVL system 468 had the same type of polypeptide spectrum; the spectra of two mutants, Risö mutant 29 and Risö mutant 86, were also similar and presented another type. Each of the three high-lysine barleys -- Risö mutant 56, Risö mutant 1508 and Hiproly -- had an individual, specific subunit pattern of hordeins. SDS-electrophoretic spectra of Risö mutant 1508 and variety Hiproly deserve special attention; Risö mutant 1508 showed the poorest spectrum (8 subunits) whereas the variety Hiproly had the richest polypeptide spectrum of hordeins (18 subunits) among all the studied barley forms.
The specificity of electrophoretic subunit patterns of seed hordeins of the high-lysine barleys may be used in testing breeding materials for the presence of the high-lysine gene.
Acknowledgment:
I wish to thank Professor Dr. hab. J. Przybylska for reviewing the
manuscript.
References:
Kapala, A. 1979. Genetica Polonica, 20: No. 1.
Kapala, A., I. Wiatroszak, and J. Przybylska. 1975. Genetica Polonica, 16:53-60.
Køie, B., J. Ingversen, A.J. Andersen, and H. Doll. 1976. In Evaluation of seed protein alterations by mutation breeding Proc. Research Coordination Meeting, Hehnenklee, 1975, IAF.A, Vienna. Pp. 55-61.
Lauriere, M. and J. Mossee. 1977. In Techniques for the separation of barley and maize proteins (B.J. Miflin and P.R. Shewry, Eds.) Commission of the European Communities, Luxembourg.
Przybylska , J. and A. Kapala. 1974. Genetica Polonica, 15:231-244.
Shewry, P.R., J.R.S. Ellis, H.M. Pratt and B.J. Miflin. 1978a. J. Sci. Fd. Agric., 29:433-441.
Shewry, P.R., H.M. Pratt, M.J. Charlton and B.J. Miflin. 1977. J. Exp. Bot., 28:597-606.
Shewry, P.R., H.M. Pratt and B.J. Miflin. 1978b. J. Sci. Fd. Agric., 29:587-596.
This work was supported by the Polish Academy of Sciences under Project 09.1, subproblem A part I.08-01.
