Additional Quantitative Trait Loci and Candidate Genes for Seed Isoflavone Content in Soybean

Abstract

Seed isoflavone content of soybean (Glycine max L. Merr.) is a trait of moderate heritablity and an ideal target for marker selection. To date over 20 QTL have been identified underlying this trait among seven populations. The objectives of this study were to identify additional QTL and candidate genes controlling isoflavone content in a set of recombinant inbred line (RIL) populations of soybean grown in two different seasons. Variations of isoflavones namely daidzein, glycitein and genistein contents over two growing seasons and locations suggests that isoflavones are influenced by both genes and environments. Six QTL were identified on five different chromosomes (Chr) or linkage groups (LG) that controlled daidzein (Chr_2/LG-M; Chr_17a/LG-D2), glycitein (Chr_2/LG-D1b; Chr_8/LG-A2) and genistein (Chr_8/LG-A2; Chr_12/LG-H) respectively in the seeds grown in season 2010. Two QTL were identified for daidzein (Chr_6/LG-C2; Chr_13b/LG-F), two QTLs for glycitein (Chr_1/LG-D1a; Chr_17c/LG-D2) and five QTLs for genistein (Chr_3/ LG-N; Chr_8/LG-A2; Chr_9/LG-K; Chr_18/LG-G) in the seeds of the 2011 growing season. Genes located within QTL confidence intervals were retrieved and gene ontology (GO) terms were used to identify those related to the flavonoid biosynthesis process. Twenty six candidate genes were identified that may be involved in isoflavones accumulation in soybean seeds.

A SNP genetic linkage map based on the ‘Hamilton’ by ‘Spencer’ recombinant inbred line population identified QTL for seed isoflavone contents in soybean

“…The oligo pool success rate (95.48%) is a little bit lower than the rate in our previous study (Akond et al. ) but still higher than and comparable with the success rates of 89–92% in previously reported maps such as in barley (Rostoks et al. ), soybean (Hyten et al.…”

“…, Akond et al. ), but the current map is more dense than the others. This map's genome coverage (1432.72 cM) is comparable to other SNP‐based maps reported earlier but has a high number of SNPs (1502 SNPs).…”

“…Recently, we analysed the ‘MD 96‐5722’ by ‘Spencer’ RIL population using the Infinium BeadChip genotyping array of soybean on iScan platform of Illumina and identified several important QTL for oil, protein, sugar, amino acids and isoflavones (Akond et al. ,b, ). For this study, we also analysed the ‘Hamilton’ by ‘Spencer’ RIL population using the Infinium BeadChip genotyping array of soybean using iScan platform of Illumina.…”

Expression quantitative trait loci infer the regulation of isoflavone accumulation in soybean (Glycine max L. Merr.) seed

“…Several genes involved in isoflavone accumulation in soybean seed had been identified [22, 27, 31]. 11 candidate genes falling into the overlapped intervals of pQTL and eQTL were found (Table  4).…”

Unconditional and conditional QTL underlying the genetic interrelationships between soybean seed isoflavone, and protein or oil contents

“…, Akond et al. ). QTL with additive and epistatic effects as well as environmental interactions for soybean isoflavone were also presented by Primomo et al.…”