科研之友
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摘要
Soybean Kunitz trypsin inhibitor (SKTI) has several polymorphic types, which are controlled by co-dominant multiple alleles at a single locus. Of these types, Tia and Tib are predominant types, and there are nine differences in amino acids between Tia and Tib. Recently, an intermediate transitional type (Tib(i5)) between them was detected. However, other transitional types have not been detected despite surveys of many cultivated and wild soybeans. One of the reasons why other transitional variants have not been found is inferred to be due to the difficulty of the detection of SKTI protein variants by polyacrylamide gel electrophoresis (PAGE). To detect novel variants of SKTI, nucleotide sequence analysis in addition to PAGE was carried out. Four new variants were found from many Japanese wild soybeans. Of these variants, three (designated as Tia(a1), Tia(a2), Tia(b1)) were detected through gene sequence analysis on wild soybeans having the same electrophoretic mobility as Tia, and one (Tig) was detected through PAGE. The Tig variant showed a slightly lower electrophoretic mobility than Tic. The nucleotide sequences of Tig were identical to those of Tib except for one T -> C transitional mutation at position +340. The sequences of Tia(a1) and Tia(a2) genes were identical to those of Tia with the exception of a G -> A mutation at position +376 and a T -> C mutation at +404, respectively. The sequence of Tia(b1) differed from Tia by three nucleotides: C -> A at position +331, T -> C at +459 and A -> at +484. Of the three nucleotide changes, two were common to Tia(b1), Tib(i5) and Tib, suggesting that Tia(b1) is an intermediate transitional type between Tia and Tib. Our results suggest that Tib type has been differentiated through a series of mutations from Tia before the domestication of cultivated soybean.
- 出版日期2008-8
- 单位中国农业科学院
