小麦转录因子基因TaPHR1参与调控每穗小穗数

Transcription factor gene TaPHR1 involved in regulation spikelet number per spike in common wheat

利用水分高效基因资源创制新型小麦品种是应对气候变化和人口高速增长的有效途径。MYB(v-myb avian myeloblastosis viral oncogene homolog)是植物中最大的转录因子家族之一,参与调控植物生长发育,生物和非生物胁迫。本研究在TaPHR1-4A和TaPHR1-4B中分别鉴定出19个和15个SNP,基于这些多态性位点开发了分子标记。关联分析表明,Hap-4B-I是小穗数多的优异单倍型。通过创制两个回交导入系群体,进一步证实Hap-4B-I有利于改善小麦穗部性状。TaPHR1的转录表达分析发现Hap-4B-I单倍型幼穗中TaPHR1的表达水平均高于Hap-4B-II单倍型。此外,TaPHR1在水稻中的异源表达导致穗分支变多,也证实TaPHR1参与调控每穗小穗数。小麦育成品种的时空分布分析发现尽管Hap-4B-II在我国现代育成品种中占比最多,但随小麦育种时间的推进,Hap-4B-I的占比在逐渐增多。总之,TaPHR1是小麦每穗小穗数的正调节因子。因此,本研究开发的分子标记可作为小麦标记辅助选择和遗传改良的重要来源。

The utilization of water elite genetic resources to develop new wheat varieties is an effective approach to deal with the challenges of climate change and rapid population growth.The MYB(v-myb avian myeloblastosis viral oncogene homolog)transcription factors are one of the largest families of transcription factors in plants and are involved in plant growth and development and in the regulation of biotic and abiotic stresses.In this study,19 SNPs and 15 SNPs were identified in TaPHR1-4A and TaPHR1-4B,respectively,and the molecular markers were developed based on these SNPs.Association analysis showed that Hap-4B-I was the elite haplotype with high Total number of spikelet per spike(NCS).Hap-4B-I was further confirmed to be beneficial for improving wheat spike traits by creating two backcross introgression population lines.Fluorescence quantitative polymerase chain reaction of TaPHR1 revealed that the relative expression level of TaPHR1 genes in young spikelets of Hap-4B-I haplotype was higher than that of Hap-4B-II haplotype.In addition,the heterologous expression of TaPHR1 in rice resulted in more panicle branches,which also confirmed the involvement of TaPHR1 in the regulation of NCS.The geographic and temporal distribution of wheat modern varieties revealed that although Hap-4B-II accounted for the largest proportion of modern varieties in China,the proportion of Hap-4B-I was gradually increasing as wheat breeding time progressed.In conclusion,TaPHR1 was a positive regulator of NCS in wheat.Therefore,the molecular markers developed in this study could be an important source of marker-assisted selection and genetic improvement in wheat.