PEG6000模拟干旱胁迫下银杏幼苗叶片的转录组分析

Transcriptome Analysis of Ginkgo biloba Leaves under PEG6000 Simulated Drought Stress

为研究银杏响应干旱胁迫的差异表达基因,本研究以20%(w/w) PEG6000处理后的银杏幼苗叶片和正常叶片(对照)为材料构建了15个转录组测序文库,共产生了7.88×10^8原始序列读数,经从头组装并优化过滤后得到了93 750个Unigenes。通过对不同时间点响应干旱的基因进行差异分析,共找到了4 140个差异表达基因,其中有1 953个上调,2 187个下调,在干旱过程中差异表达基因的动态响应表现为干旱处理6 h的上调差异基因数最高,干旱处理12 h的下调差异基因数最高。进一步对得到的差异表达基因进行转录因子鉴定,共鉴定出171个转录因子,其中74个上调,97个下调,主要集中在MYB (38)、AP2/ERF (26)、NAC(15)、C2C2 (13)和bZIP (6)家族,且转录因子数在干旱处理6 h达到高点。GO富集分析显示,碳水化合物代谢与细胞壁大分子代谢占生物学过程最多,细胞膜的组成部分与细胞外区域显著富集在细胞组分中,水解酶活性占分子功能最多。KEGG富集分析显示,差异表达基因显著富集在苯丙烷生物合成、植物激素信号转导、植物昼夜节律以及淀粉和蔗糖代谢等通路中。上述研究结果可为银杏对抗干旱胁迫的分子调控机制探究提供理论依据。

In order to explore the differentially expressed genes of Ginkgo biloba in response to drought stress,this study constructed 15 transcriptome sequencing libraries using 20%(w/w) PEG6000 treated leaves and normal leaves(control) as materials,and a total of 7.88×10^8 original sequence reads were generated. After assembly and optimized filtering, 93 750 Unigenes were obtained. Through differential analysis of genes responding to drought at different time points, a total of 4 140 differentially expressed genes(DEGs) were found, of which 1 953 were upregulated and 2 187 were down-regulated, during drought, the dynamic response of differentially expressed genes showed that the number of differential genes up-regulated at 6 h in drought treatment was the highest, and the number of differential genes up-regulated at 12 h in drought treatment was the highest. Further identification of the transcription factors of the differ entially e xpressed genes, a total of 171 transcription factors were identified, of which 74 were up-regulated and 97 were down-regulated, mainly concentrated in MYB(38), AP2/ERF(26), NAC(15), C2 C2(13) and bZIP(6) family, and the number of transcription factors reached a high point at 6 h of drought treatment. GO enrichment analysis showed that carbohydrate metabolism and cell wall macromolecule metabolism accounted for the most biological processes, cell membrane components, and extracellular regions were significantly enriched in cell components, and hydrolase activity accounted for the most molecular functions.KEGG enrichment analysis showed that differentially expressed genes were significantly enriched in metabolic pathways including phenylpropane biosynthesis, plant hormone signal transduction, plant circadian rhythm, and starch and sucrose metabolism. This study could provide a theoretical basis for studying the molecular regulation mechanism of drought resistance of Ginkgo biloba.