利用全基因组关联分析挖掘高粱单宁新调控遗传位点

Identification of new tannin loci in sorghum using genome-wide association study

单宁是高粱重要的籽粒品质性状之一,单宁含量的高低直接影响其用途。调控单宁含量Tan1和Tan2基因虽被克隆,但并不能完全解释高粱籽粒中单宁含量高低的现象,因此调控单宁含量必定还存在其他的新基因。利用300份和202份(去除98份含有tan1-a和tan1-b基因型的材料)自然群体材料的单宁含量表型数据以及重测序获得的4 842 629个SNPs,采用全基因组关联分析方法挖掘调控单宁含量新遗传位点及候选基因。共获得25个显著关联区间、共有40个候选基因,其中Sobic.001G041500和Sobic.006-G180300是bHLH转录因子, Sobic.001G398100和Sobic.001G398200是MYB转录因子, Sobic.002G044200与类黄酮-3′,5′-羟化酶高度同源。类黄酮合成途径是合成单宁的必经过程, 5个候选基因均参与类黄酮合成途径,也可能参与单宁的生物合成。新单宁调控遗传位点及候选基因的挖掘为深入研究高粱单宁调控的遗传机制提供分子依据。

Tannin content is one of the important grain quality traits of sorghum,and can directly affect its uses.Although Tan1 and Tan2,regulating tannin contents,have been cloned,they could not completely explain the phenomenon of tannin content in sorghum grains,so there must be other new genes that regulate tannin content.In this study,grain tannin contents of 300 and 202(removed 98 sorghum materials containing tan1-a and tan1-b genotypes)sorghum materials and 4842629 SNPs obtained by resequencing were used to explore new genetic loci and candidate genes which regulate tannin content by genome-wide association study(GWAs).25 significant association regions and 40 candidate genes were obtained,Sobic.001G041500 and Sobic.006G180300 are bHLH transcription factors,Sobic.001G398100 and Sobic.001G398200 are MYB transcription factors,and Sobic.002G044200 is highly homologous to flavonoid 3',5'-hydroxylase(F3'5'H).The flavonoid synthesis pathway is a necessary process for tannin synthesis.These five candidate genes are all involved in the flavonoid synthesis pathway,and may be also involved in tannin biosynthesis.The new tannin-regulated genetic loci and candidate genes will provide molecular basis for in-depth studying tannin genetic regulation mechanism in sorghum.