| The ralative contents of Glycinin(11S) and β-Conglycinin(7S), the composition of its subunits and percentage contents of different subunits in seeds of 828 soybean genotypes were analysed using SDS-PAGE technique,the rules of its variance , its stabilities between years and relationships with the contents of total protein and oil were also studied; the ralationships between 11S/7S ratios and functional properties of soybean protein were analysed.The results were as follows:In this study,sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that the 11S included bands corresponding to A3-subunit ,A1aA1bA2A4(acidic subunit,A-subunit) and basic subunit(B-subunit);that the 7S contained α '-subunit, α - subunit and β -subunit.There was plentiful variation in the composition of seed storage protein of soybean. Range of the specific values of 11S relative content was 37.5% -81.42%,and mean value was 60.30%, coefficient of genetic variation was 8.84% ;range of the relative content of 7S was 18.58% -62.42%, and mean value was 39.70%,coefiicient of genetic variation was 13.43%;range of the specific values of 11S/7S ratios was 0.60-4.38,which averaged 1.56,coefficient of genetic variation was 23.08%.There were significant differences among varieties in the relative content of 11S or 7S fraction and 11S/7S ratios.The results indicated the exploitation of soybean protein with abundant resources has great potentiality.The contents of subunits of 11S and 7S fractions from different soybean genotypes have shown much variation.Range of the specific values of a '-subunit content was 3.91%-18.18%, and mean value was 10.40%;the content of α-subunit was 4.04%-31.31%,which averaged 16.90%;range of the content of P -subunit was 6.75%-23.34%,and mean value 12.48%; the composition of A3-subunit was 3.27%-16.99%,which averaged 9.39%;range of values of A-subunit content was 3.22%-36.63%,and mean value was 22.5%; range of values of B-subunit content was 10.23%-64.23%, and mean value was 28.30%.There were significant differences among varieties in the contents of subunits.Correlation analysis indicated that the content of 11S was correlated negatively with that of 7S(r = -0.970**, n =828). So it was possible to breed soybean lines with a high 11S or 7S content without causing a reducting in the total protein or oil content.The composition of total protein or oil in soybean seeds was not correlated with that of 11S or 7S fraction .Though there was not a correlation between a - subunit content and a '-subunit or A3-subunit content,there were correlations between another subunit contents.The content of another subunit except A3-subunit was not markly correlated with the content of 11S or 7S fraction; α - subunitcontent was correlated positively with the composition of oil or total protein in soybean seeds,but another content was not correlated with that of oil or total protein . So changing subunit content did not reduce the nutritional value of soybean.We identified five mutant soybean lines,one containning a high 11S content(81.24%),one containing a high 7S content(62.42%),one lacking the A3-subunit,one lacking the a ' -subunrit, the a -subunit and A3-subunit and having a low level of the A-subunit and high levels of both β -subunit and B-subunit,one having another strong bands between the a -subunit and β-subunit bands.The output of cluster analysis showed the 100 soybean varieties were divided into three groups.The first group was composed of 36 varieties from Heilongjiang, Jilin, Liaoningx Shanxi and Xinjiang provinces ;The second one was composed of 12 varieties from Beijing and Heinan province;The third one was composed of 52 varieties from Hunan, Guangdong, Jiangshu, zhejiang and Fujian provinces. There appeared significant geographical distribution for 11S and 7S fraction of soybean varieties.There were no significant differences in the content of 11S and 7S, 11S/7S ratios and subunit content in 2001 and those in 2002.The functional properties of soybean protein were closely related to 11S...
|
PDF Full Text Request