Definition of Soybean Genomic Regions That Control Seed Phytoestrogen Amounts

[摘要] Soybean seeds contain large amounts of isoflavones orphytoestrogens such as genistein, daidzein, and glycitein thatdisplay biological effects when ingested by humans and animals.In seeds, the total amount, and amount of each type, ofisoflavone varies by 5 fold between cultivars and locations.Isoflavone content and quality are one key to the biologicaleffects of soy foods, dietary supplements, and nutraceuticals.Previously we had identified 6 loci (QTL) controlling isoflavonecontent using 150 DNA markers. This study aimed to identify anddelimit loci underlying heritable variation in isoflavone contentwith additional DNA markers. We used a recombinant inbred line(RIL) population (n=100) derived from the cross of “Essex” by“Forrest,” two cultivars that contrast for isoflavone content.Seed isoflavone content of each RIL was determined by HPLC andcompared against 240 polymorphic microsatellite markers byone-way analysis of variance. Two QTL that underlie seedisoflavone content were newly discovered. The additional markersconfirmed and refined the positions of the six QTL alreadyreported. The first new region anchored by the markerBARC-Satt063 was significantly associated with genistein(P=0.009,R2=29.5%) and daidzein (P=0.007,R2=17.0%).The region is located on linkage group B2 and derived thebeneficial allele from Essex. The second new region defined bythe marker BARC-Satt129 was significantly associated with totalglycitein (P=0.0005,R2=32.0%). The region is located onlinkage group D1a+Q and also derived the beneficial allele fromEssex. Jointly the eight loci can explain the heritable variationin isoflavone content. The loci may be used to stabilize seedisoflavone content by selection and to isolate the underlyinggenes.

[学科分类] 基础医学