RNA-seq挖掘四倍体小麦紫籽主效基因

Major Genes of Purple Seeds in Tetraploid Wheat Excavated by RNA-seq

紫色籽粒四倍体小麦籽粒中富含花青素,是优良的遗传学标记,但其分子遗传机理尚不清楚。本研究利用RNA-seq技术比较四倍体小麦紫粒品种‘深紫1号’和白粒品种‘高原3号’果皮转录组,挖掘控制紫粒性状的主效基因。结果表明紫色和白色果皮中共检测到95 404个Unigenes。21 373个基因表达差异显著,其中3 891个基因在紫色果皮表达上调,12 482个基因表达下调。差异表达基因主要与次生代谢途径相关,其中黄酮类和花青素合成代谢通路差异最为明显。除F3’H外,与花青素合成相关的结构基因在紫色果皮中的表达水平均高于白色,说明花青素合成代谢与四倍体小麦的紫粒性状相关。调控花青素合成代谢的MYC转录因子Unigene25029_All位于2AL染色体上,在紫色果皮中表达水平比白色果皮高出4.78倍,与普通小麦中控制紫粒性状的TaMYC1 (pp3)同源,这个基因很有可能就是四倍体小麦紫色果皮性状的候选基因。本研究结果筛选到四倍体小麦中紫粒性状的候选基因,有助于了解小麦紫色果皮性状的起源及其分子机理的解析。

The purple seeds of tetraploid wheat are rich in anthocyanin, which is an excellent genetic marker, but its molecular genetic mechanism is not clear. In this study, the transcriptome of its pericarp was compared with’Purple1’ and ’Gaoyuan3’ for digging the key genes responsible for controling the purple grain character. The results showed that 95 404 unigenes were detected in purple and white pericarp. There were 21 373 Unigenes significantly differentially in expression, including 3 891 up-regulated in purple pericarp and 17 482 down-regulated in white percicrap. The differentially expressed unigenes were mainly involved in secondary metabolic pathways, among them, the flavonoid biosynthesis pathway was the most represented in metabolic pathways. Most structural genes related to anthocyanin biosynthesis had higher expression level in purple than white except F3’H, which implied that anthocyanin biosynthesis was related to purple grain traits of tetraploid wheat. The MYC transcription factor Unigene25029_All was located on chromosome 2 AL, and its expression level in purple pericarp was 4.78 times higher than that in white pericarp, and homologous to TaMYC1(pp3), which controls purple pericarp in common wheat. This gene was likely to be a candidate for purple pericarp traits in teraploid wheat. In this article, candidate gene for purple pericarp traits in teraploid wheat was screened, which might be helpful to understand the origin and molecular mechanism of purple pericarp traits in wheat.