Study Of Seed Protein Subunits On Resources Of Genus Fagopyrum

Seed protein subunits of 75 accessions of 10 buckwheat species (including 7 species of big-achene group and 3 species of small-achene group) were studied by means of SDS-PAGE. The results showed:(1)There were great variations of seed protein subunits within the same buckwheat species and among different buckwheat accessions. There are 42 different subunits in the seven buckwheat species of the big-achene group, much more than those in the small-achene group with only 16 seed protein subunits. And different types of buckwheat have some different special subunits, which could be used to identify the species of genus Fagopyrum. The result of the cluster analysis showed that common buckwheat, wild common buckwheat and F.esculentum var. homotropicum are close to each other and tartary buckwheat are close to wild tartary buckwheat. In the small-achene group, F.gracillips and F.pleioramosum have the close relationship. There are 39 bands of seed protein subunits in different common buckwheat accessions, and their surface molecular weight has a big range, 10-75kDa. All common buckwheat accessions share seed protein subunits SSP_63.1, SSP_44.6, SSP_33.8, SSP_23.9, and SSP_17.4. There are 28 bands of seed protein subunits in tartary buckwheat accessions, and all tartary buckwheat accessions have common bands SSP_35.2, SSP_23.9, and SSP_20.9. Thirty-three seed protein subunits were found in wild buckwheat accessions. According to number and distribution of seed protein subunits, wild common buckwheat is close to F.megaspartanium and F.esculentum var. homotropicum, while tartary buckwheat is close to F.pilus, F.cymosum, and F.giganteum.(2) There were 33 bands of seed protein subunits in common buckwheat (Sobano), and 31 bands in F.esculentum var. homotropicum. Cotyledon has most of seed protein subunits, much more than endosperm. Sobano has the special subunits SSP37.4, SSP39.9, SSP44.7, SSP42.9, SSP49.8, SSP57.4, SSP60.4, SSP62, and SSP73.5, and F.esculentum var. homotropicum SSP36.5, SSP37.8, SSP40.6, SSP44.0, SSP51.4, SSP59, SSP64.9, SSP72.7, and SSP74.6.(3) The results on progenies of hybrids of the cross Sobano×F. esculentum var. homotropicum showed that four pairs of co-dominant alleles control four pairs of protein subunits (SSP62 /SSP59,SSP49.8 / SSP51.4,SSP44 / SSP42.9, SSP39.9 / SSP37.8) respectively and may be independent to each other.(4) The genetic analysis of morphological characters indicated that acute chene, shattering habit, homostyle were cotrolled by different dominant single gene.(5)The linkage analysis showed that shattering habit and SSP44/SSP42.9 were linked with an exchange ratio of 22.6%, homostyle and shattering habit were much close linked to each other with an exchange ratio of 3.91%. Acute achene and seed protein subunits (SSP59/SSP62, SSP49.8/SSP51.4, SSP39.9/SSP37.8) belong to different linkage groups respectively.