大豆异黄酮12种组分全基因组QTL扫描和优异等位变异及特异材料发掘

Discovery of elite alleles for isoflavone content would be desirable to breeding soybean [Glycine max (L.) Merr.] seeds with desirable isoflavone content. Isoflavone in soybean exists in 12 various chemical forms, including aglucones (daidzein, genistein and glycitein), β-glucosides (genistin, daidzin and glycitin) and β-glucosides conjugated with malonyl (6"-O-malonyldaidzin, 6"-O-malonylgenistin and 6"-O-malonylglycitin) and acetyl groups (6"-O-acetyldaidzin, 6"-O-acetylgenistin and 6"-O-acetylglycitin) with biological activities, each of which exerts diversely effects of both plant and human health. Although some QTLs linked with total daidzein, genistein, glycitein content and total isoflvone content were detected by linkage mapping based on RILs populations, it was hardly practical in breeding program due to their polygenic and complex genetic basis. A large variation in total isoflavone (the ranged of 259.38-7932.94 μg g-1) and its 12 components both in cultivated and wild soybeans was observed in our previous study. Based on quantifying 12 isoflavones content, we assumed that it was practical to genome-widely map elite alleles of isoflavone content both in cultivated and wild soybeans population, and it has not been reported so far. This proposal is undertaken to (1) scan QTLs as well as their alleles on a genome-wide scale associated with content of all 12 individual isoflavones between SSR molecular markers on the total of 1000 samples consisted of landraces of Glycine max (L.) Merr. and wild accessions of Glycine soja Sieb. et Zucc., (2)screen out elite alleles as candidate genes from the QTLs acquired both in the association mapping from natural population of soybean germplasm and linkage mapping from NJRIKY and NJRISX population previously fully utilizing the information of soybean genome and isoflavone metabolism gene in public, (3) identify of the elite alleles and specific accessions associated with them by gene sequencing and real-time fluorescent quantitative PCR and bioinformatics technique based on the exactly measuring 12 isoflavones content in seeds of soybean from 4 cropping years at 3 locations using primers and genetic materials designated. The results achieved will be useful for developing soybean varieties with desirable isoflavone content.

发掘显著提高大豆异黄酮含量优异基因，对大豆品质育种意义重大，也是当前亟待解决的问题。大豆异黄酮包含三大类型12种组分，各组分功效不同。目前虽连锁定位了不少QTL，但因其遗传机制复杂，育种利用尚难实现。本团队前期研究发现，大豆种质异黄酮各组分及其总含量变幅（259.38-7932.94 μg g-1）均很大。推测在精确测定种质资源群体12种组分基础上，全面搜索显著提高异黄酮含量优异等位变异有实际意义，而迄今国内外尚无报道。本项目拟在现有研究基础上，借助SSR分子标记进行大范围栽培和野生资源12种异黄酮组分及其总含量的关联定位，全基因组扫描搜索有利等位变异；结合连锁定位及文献报导定位结果,根据公布的大豆全基因组和异黄酮代谢基因序列信息，筛查所获重要位点内高置信候选基因；设计引物和遗传材料，在连续4年3地精确的表型鉴定基础上，发掘稳定的优异候选基因及特异载体材料，为种质创新和分子育种提供基础。

大豆异黄酮是大豆及其制品的重要活性物质，也是重要的植物保护素，包含三大类型12种组分，各组分功效不同。因其遗传机制复杂，分子标记辅助选择被认为是育种利用的有效途径。本研究围绕发掘大豆异黄酮12种组分优异等位变异和特异载体材料目标完成预定研究工作，并对其功能解析及育种利用展开了相关的研究。利用Agilent 1200高效液相色谱系统，精确鉴定了不同遗传背景、有代表性的资源群体、近等基因系和杂交后代品系3地4年田间试验所获籽粒、叶、根12种异黄酮组分，利用国家大豆改良中心建立的相关高密度遗传图谱全基因组扫描搜索异黄酮含量优异等位变异，并对上述数据进行遗传多样性分析和性状的遗传解析。结果获得了各组分的潜在决定性QTL及基因区段和等位变异，而且掌握了这些等位变异在各地理生态型间的传递规律，发掘了一批相对稳定具有不同异黄酮组分特异性等位变异及其特异载体材料。以此为基础，通过正向和反向遗传学相结合的策略揭示了控制异黄酮不同组分的遗传与基因调控特点，并对其他相关性状展开研究；同时通过不断杂交重组，创制了一批异黄酮特异新种质，培育了综合性状优良的3个新品系，表明该性状具有重大育种利用价值。发表SCI论文2篇。培养博士研究生1人、本科生33人。