Changes in storage protein composition on genetic removal of Kunitz trypsin inhibitor maintain protein content in soybean (Glycine max)

Abstract

Genetic removal of Kunitz trypsin inhibitor (KTI), a proteinaceous anti-nutritional factor, in soybean is anticipated to cause loss in protein content. In the present study, marker-assisted survey of 180 recombinant inbred lines (RILs) developed from the cross KTI ​+ ​ve (‘SL525’) ​× ​KTI-free parent (‘NRC101’) in tandem with quantification of protein content led to the identification of KTI-free RILs with normal-protein content. SDS-PAGE analysis of KTI-free parent, KTI ​+ ​ve parent, low-protein KTI-free, and 2 normal-protein KTI-free RILs showed random increase and decrease in the concentration of different subunits of glycinin (11S), β-conglycinin (7S) and other storage protein in the normal-protein KTI-free RILs compared to KTI ​+ ​ve parent. KTI-free RILs with normal-protein content showed higher concentration of acidic and basic subunits of 11S and β-subunit of 7S fraction compared to the low-protein KTI-free RIL and KTI-free parent. The study suggested that it is possible to breed KTI-free soybean without reducing the protein content.

Keywords

• Kunitz trypsin inhibitor
• Genetic elimination
• Soybean
• β-Conglycinin
• Glycinin
• Protein content