Introgression of null allele of Kunitz trypsin inhibitor through marker-assisted backcross breeding in soybean (Glycine max L. Merr.)

Abstract

BackgroundPresence of Kunitz trypsin inhibitor (KTI) in soybean seeds necessitates pre-heat treatment of the soy-flour for its inactivation before using it in food and feed products. The heat treatment not only enhances processing costs of the soy-based foods and feeds but also affects seed-protein quality and solubility. Genetic elimination of KTI is an important and effective approach. Therefore, molecular marker-assisted backcross breeding (MABB) approach was adopted for genetic elimination of KTI from two popular soybean genotypes, DS9712 and DS9814. PI542044, an exotic germplasm line was used as donor of the kti allele which inhibits functional KTI peptide production.ResultsForeground selection for the kti allele was performed with three closely linked SSR markers while background selection was done with 93 polymorphic SSR markers. Plants in the BC1F1 generation were found to recover 70.4–87.63 % and 60.26–73.78 % of the recurrent parent genome (RPG) of DS9712 and DS9814, respectively. Similarly, selected plants in the BC2F1 generation had 93.01–98.92 % and 83.3–91.67 % recovery of their respective RPGs. Recombinant selection was performed so as to identify plants with minimal linkage drag. Biochemical analysis of the seeds of the selected plants (ktikti) confirmed absence of KTI peptides in the seeds. Phenotypically, the selected plants were comparable to the respective recurrent parent in yield and other traits.ConclusionsMABB approach helped in speedy development of 6 KTI free breeding lines of soybean. Such lines will be suitable for the farmers and the soybean industries to use in production of soy-based foods and feeds without pre-heat treatment of the soy-flour. It would contribute towards wider acceptability of soy-based foods and feeds.Electronic supplementary materialThe online version of this article (doi:10.1186/s12863-016-0413-2) contains supplementary material, which is available to authorized users.

Trypsin Inhibitor Assessment with Biochemical and Molecular Markers in a Soybean Germplasm Collection and Hybrid Populations for Seed Quality Improvement

“…Finally, segregants with ti3/ti3 genotypes were successfully verified for low KTI content and propagated for further yield analysis and development of prospective breeding lines. Our results were similar to those published earlier on the introgression of the null-allele ti3 and MAS to select recombinant genotypes with low KTI content in an Indian soybean breeding program [16,17]. Hybridization and transference of the beneficial ti3 null-alleles determining low KTI in seeds using MAS is very important to enhance the market value and overall soybean seed quality in Kazakhstan.…”

“…The introgression of the ti null-allele at BC 2 F 2 and BC 3 F 2 generations was controlled by Marker-assisted selection (MAS) with ti allele-specific primers and linked SSR markers. Nine and six breeding lines with genetic backgrounds of JS97-52 and DS9712 / DS9814 recurrent parents, respectively, were obtained in Indian breeding programs [16,17]. The introgressed null-allele ti was confirmed in the breeding lines and the KTI content was reduced by 69-84% [16] and an additional seed yield improvement was reported [17].…”

From proteomics to ionomics: Soybean genetic improvement for better food safety

“…The Kunitz null trait has been introgressed into different genetic backgrounds and has been utilized to develop soybean cultivars with reduced trypsin inhibitor activity (e.g. BERNARD and HYMOWITZ 1986;BERNARD et al, 1991;VOLLMANN et al, 2003;ALVES DE MORAES et al, 2006;RANI et al, 2011;PERIC et al, 2014;MARANNA et al, 2016; HERMAN and SCHMIDT, 2016; TALUKDAR and SHIVAKUMAR, 2016). In Serbia, for example, Kunitz null soybean cultivars Lana and Laura have been developed for easier livestock feeding and more economical food processing (PERIC et al, 2014).…”

“…chromosome 9) and gene specific primers are available now for assisting in the introgression of that trait (e.g. ALVES DE MORAES et al, 2006;KIM et al, 2006;RANI et al, 2011;KUMAR et al, 2013;KUMAR et al, 2015;MARANNA et al, 2016).…”

QTLomics in Soybean: A Way Forward for Translational Genomics and Breeding

“…The two SSR markers linked with SCN resistance rhg1 locus were further validated by Silva et al (2007) and found that only a combination of two markers provide selection efficiency of 100%. Shivakumar et al (2016) employed MABC for conversion of two high Kunitz trypsin inhibitor (KTI) content soybean varieties (DS 9712 and DS 9814) into low KTI soybean genotypes using three SSR markers. Rosso et al (2011) has developed breeder friendly markers for D-myo-inositol 3-phosphate synthase 1 gene ( MIPS1 ) which causes modifications to seed phosphorus and carbohydrate content in soybean.…”