Genetic elimination of Kunitz trypsin inhibitors (KTI) from DS9712, an Indian soybean variety

Abstract

In this study, the null allele of Kunitz trypsin inhibitor i.e. kti was transferred from PI542044, a germplasm line free from KTI in to a popular Indian soybean variety DS9712 through marker assisted backcross breeding (MABB) approach. Following foreground selection with 3 SSR markers viz., Satt228, Satt429 and Satt409 that are linked to kti, and background selection with 93 polymorphic SSR markers in BC1F1 and BC2F1 generations, target plants were selected that had 96-98% recovery of the recurrent parent genome (RPG). In BC2F2 generation, plants homozygous the for target allele (kti kti) were identified and harvested individually. In BC2F3 generation, seed proteins of the selected lines were extracted and analyzed through native polyacrylamide gel electrophoresis (PAGE) and confirmed absence of the KTI peptides. Four lines were identified that were free from Kunitz trypsin inhibitor but retained nearly all of the phenotypic features of DS9712.This study exemplified successful elimination of KTI from soybean seeds through MABB approach.