干旱胁迫下过表达TaER小麦的转录组及光合特性分析

Transcriptome and Photosynthetic Trait Analysis of TaER Over-expression Wheat under Drought Stress

为探究小麦TaER基因调控蒸腾效率及抗旱性的分子机制,以2个T3代转TaER基因株系及其野生型为材料,对其正常灌溉和干旱胁迫处理下的灌浆期旗叶进行转录组(RNA-seq)测序,分析其差异表达基因并进行GO和KEGG富集分析,探究其功能及可能参与的调控通路,同时测定光合及蒸腾参数。结果表明,与野生型相比,TaER过表达株系在正常灌溉和干旱胁迫下分别获得1 439和607个共同的差异表达基因;GO富集分析发现,光合作用、脂质和膜脂代谢基因响应干旱胁迫;KEGG富集分析表明,亚油酸和α-亚麻酸代谢中的酯氧合酶、甘油脂代谢中的糖基转移酶基因均上调表达,光合作用相关基因响应干旱胁迫;干旱胁迫下,TaER过表达株系的净光合速率和水分利用效率较高,蒸腾速率较低。综上所述,TaER过表达株系可能是通过调控脂类代谢及光合作用等生物过程,提高光合速率及水分利用效率,从而适应干旱胁迫的。

In order to explore the molecular mechanism of wheat TaER gene in regulating transpiration efficiency and drought resistance,two T3 generation TaER transgenic lines and their wild type were used as materials.The TaER over-expressing lines L1,L2 and the wild type were grown in normal irrigation and drought stress conditions,and the flag leaves at grain-filling stage were used for transcriptome analysis by RNA-seq.The differentially expressed genes(DEGs)between wild type and over-expression lines were annotated with Gene Ontology(GO)and KEGG database to understand the functions and the regulation pathways,and the photosynthetic and transpiration traits were also investigated.Both over-expressing lines showed 1 439 and 607 common DEGs under normal irrigation and drought stress compared with the wild type,respectively;The GO expression enrichment analysis of DEGs showed that the photosynthesis,lipid and membrane lipid metabolism-related genes in TaER over-expressed strains responded to drought stress;KEGG enrichment analysis indicated that lipoxygenase genes of linoleic acid metabolism andα-linolenic acid metabolism were up-regulated,and glycosyltransferase genes of glyceride metabolism were up-regulated,and the photosynthesis-related genes responded to drought stress.The net photosynthetic rate and instantaneous water use efficiency of TaER over-expression lines was increased,and transpiration rate was decreased under drought stress.In summary,TaER over-expression lines may be adapted to drought stress by regulating biological processes such as linoleic acid metabolism and photosynthesis to increase photosynthetic rate and transpiration efficiency.