Kunitz Trypsin Inhibitor Polymorphism In The Korean Wild Soybean (Glycine Soja Sieb. & Zucc.)

Kunitz trypsin inhibitor (KTi) in 1368 accessions of wild soybean (Glycine soja Sieb. & Zucc.), collected from three regions of Korea, was examined for allelic diversity and geographical distribution. Five electrophoretically distinguishable KTi forms were detected: three were common (Tia, Tib and Tia/Tib) and two were previously unreported (Tib^i7-1 and Tibⁱ⁵). The Tia allele was predominant (93.49%). Alleles Tib, Tib^i7-1 and Tibⁱ⁵ were detected with the frequencies of 3.47, 0.55 and 0.11%, respectively. The heterozygous form (Tia/Tib) was detected with the frequency of 2.26%. The nucleotide sequence of Tib^i7-1 was identical to that of the Tib-derived variant allele Tif, with the exception of three nucleotides: A→G at position +244, A→C at position +286 and G→C at position +601. The latter two were similar to Tia, suggesting that Tib^i7-1 is an intermediate allele between Tia and Tib. The gene for Tibⁱ⁵ showed 100% similarity with the Japanese intermediate allele Tibⁱ⁵. This study demonstrates that Korean wild soybeans are remarkably rich source of new KTi alleles not reported before.