Soybean [Glycine max (L.) Merr.] seeds are abundant in high-quality proteins and fats. In addition, soybean seeds are also rich in secondary metabolites, such as isoflavones, lecithin, and saponins. Triterpene saponins are major components of these physiologically active metabolites in soybean seeds. Soybean saponins are classified as group A and DDMP saponins. Among them group A saponins are undesirable component of food products due to bitterness and astringency and also cause foaming in tofu production. Whereas, DDMP saponins and their derivatives are less bitter and astringent and beneficial to human health when consumed as regular diet. Therefore, reducing the group A saponins or increasing the DDMP saponins are required to improve the food quality. The present study focused to identify and characterize the gene which is encoding a protein responsible for biosynthesis of DDMP saponins. EMS mutant lines (sg-7-1 & sg-7-2) which lack DDMP saponins were developed. The breeding cross has been made with these two mutants with two cultivars, Pungsannamul and Wooram to study the segregation and genetic linkage analysis, respectively. The segregation analysis showed that the mutant phenotype is controlled by single recessive gene. TLC analysis for phenotyping F2 population of Wooram X sg-7-1 showed mutant, wild and heterozygous types. To surprise two more patterns were detected and they were named as strange type1 (ST1) and strange type2 (ST2). Further, SSR marker analysis will be carried out to locate the gene which encoding a protein responsible for biosynthesis of DDMP saponins.

Soybean germplasm have diverse accessions with great variation in their ability to survive and reproduce under salt stress conditions. In general, cultivated soybeans are more sensitive to salt stress than their wild relatives, however exceptions are found in both the groups. These variations in response to salt stress makes soybean germplasm an interesting collection of genetic resources to be explored for the identification of salt-tolerance genes, and their mechanism of action. Here, in this report we presented a data showing differential response of selected accessions of both cultivated and wild soybeans to salt stress. Two modes of salt treatment; gradual salt stress (GS) as well as salt shock (SS) were used in this study. The GS was found more effective in finding the difference in response of soybean accessions to salt stress. Various genetic marker based methods are in use to identify and isolate the potential genes contributing to the salt tolerance in soybean. Even then there is a paucity of knowledge on the key genes contributing to the salt tolerance in soybean. We expect that a recently developed functional screen based method, like yeast based functional screen, using cDNA library generated from different salt tolerant accessions of soybean could lead to identification of novel genes responsible for salt tolerance in soybean. Also, we propose for the use of RNA isolated from different stages of GS and SS for making cDNA library to be used for functional screening.