Key Laboratory of Soybean Biology in Chinese Ministry of Education (Key Laboratory of Soybean Biology and Breeding/Genetics of Chinese Agriculture Ministry), Northeast Agricultural University, Harbin, 150030, China.
Institute of Crop Science, National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
Plant J. 2020 Nov;104(4):950-963. doi: 10.1111/tpj.14972. Epub 2020 Sep 22.
Isoflavone, a secondary metabolite produced by Glycine max (L.) Merr. (soybean), is valuable for human and plant health. The genetic architecture of soybean isoflavone content remains unclear, however, despite several mapping studies. We generated genomic data for 200 soybean cultivars and 150 recombinant inbred lines (RILs) to localize putative loci associated with soybean seed isoflavone content. Using a genome-wide association study (GWAS), we identified 87 single-nucleotide polymorphisms (SNPs) that were significantly associated with isoflavone concentration. Using linkage mapping, we identified 37 quantitative trait loci (QTLs) underlying the content of four isoflavones found in the RILs. A major locus on chromosome 8 (qISO8-1) was co-located by both the GWAS and linkage mapping. qISO8-1 was fine mapped to a 99.5-kb region, flanked by SSR_08_1651 and SSR_08_1656, in a BC F population. GmMPK1, encoding a mitogen-activated protein kinase, was identified as the causal gene in qISO8-1, and two natural GmMPK1 polymorphisms were significantly associated with isoflavone content. Overexpression of GmMPK1 in soybean hairy roots resulted in increased isoflavone concentrations. Overexpressing GmMPK1 in transgenic soybeans had greater resistance to Phytophthora root rot, suggesting that GmMPK1 might increase soybean resistance to biotic stress by influencing isoflavone content. Our results not only increase our understanding of the genetic architecture of soybean seed isoflavone content, but also provide a framework for the future marker-assisted breeding of high isoflavone content in soybean cultivars.
异黄酮是大豆（Glycine max (L.) Merr.）产生的一种次生代谢产物，对人类和植物的健康都很有价值。尽管已经进行了几项图谱研究，但大豆异黄酮含量的遗传结构仍不清楚。我们生成了 200 个大豆品种和 150 个重组自交系 (RIL) 的基因组数据，以定位与大豆种子异黄酮含量相关的假定基因座。通过全基因组关联研究 (GWAS)，我们鉴定出 87 个与异黄酮浓度显著相关的单核苷酸多态性 (SNP)。通过连锁作图，我们鉴定出 37 个与 RILs 中发现的四种异黄酮含量相关的数量性状基因座 (QTL)。染色体 8 上的一个主要基因座 (qISO8-1) 同时被 GWAS 和连锁作图所定位。qISO8-1 被精细定位到一个 99.5-kb 的区域，该区域位于 SSR_08_1651 和 SSR_08_1656 之间，在 BC F 群体中。编码丝裂原活化蛋白激酶的 GmMPK1 被鉴定为 qISO8-1 的候选基因，两个天然的 GmMPK1 多态性与异黄酮含量显著相关。在大豆毛状根中过表达 GmMPK1 会导致异黄酮浓度增加。在转基因大豆中过表达 GmMPK1 会增加对 Phytophthora 根腐病的抗性，这表明 GmMPK1 可能通过影响异黄酮含量增加大豆对生物胁迫的抗性。我们的研究结果不仅提高了我们对大豆种子异黄酮含量遗传结构的理解，还为未来利用大豆品种高异黄酮含量进行标记辅助选择育种提供了框架。
