三峡库区消落带野生狗牙根对水淹适生性的转录组分析

Transcriptome analysis of the adaptability of wild Cynodon dactylon in the Fluctuating Belt of Three Gorges Reservoir during flooding

为探究狗牙根对水淹环境的适生性机制,取长势一致的狗牙根分为未水淹对照组(A1)和30 cm沉水处理组(A2),A2水淹15 d后两组同时采样,提取样本总RNA作转录组测序。A1和A2测序数据经de novo组装分别获得128031和83363条高质量Unigene;A1和A2对比发现28844条差异表达基因(differentially expressed genes,DEGs),其中11858条DEGs上调表达,16986条DEGs下调表达;功能注释显示,这些DEGs主要集中在转录、翻译、碳水化合物代谢和环境适应等途径;信号通路富集显示,包括植物对病原体的防御、物质代谢、光合作用、形态发育和抗氧化等过程的103个信号通路与狗牙根对水淹生境的适生性有关;随机挑选4个DEGs作qRT-PCR分析,荧光定量结果与测序数据基本一致,说明基于转录组分析DEGs的表达情况较为可靠。研究可为进一步挖掘与狗牙根水淹适生性相关的调控基因和功能基因提供基础。

To explore the adaptive mechanism of Cynodon dactylon under flooding,Cynodon dactylon plants with similar growth were divided into a non-flooded control group ( A1) and a treatment group ( A2). The latter consisted of a submersion depth of 30 cm. After submergence of A2 for fifteen days,sampling of the two groups was carried out simultaneously. Thereafter,the total RNA of the samples was extracted for transcriptome sequencing. The de novo sequencing data of A1 and A2 revealed 128031 and 83363 high-quality unigenes,respectively. 28844 differentially expressed genes (DEGs) were found between A1 and A2,of which 11858 DEGs were up-regulated and 16986 were down- regulated. Functional annotation showed that these DEGs were mainly concentrated in the transcription,translation, carbohydrate metabolism,and environmental adaptation. The results of signal pathway enrichment showed that 103 signaling pathways, including plant defense responses against pathogens, metabolism, photosynthesis, individual fitness development,and antioxidant activity,were related to the adaptability of Cynodon dactylon to flooding. DEGs were randomly selected for real-time quantitative reverse transcription PCR ( qRT-PCR),and the results of quantitative analysis of fluorescence were the same as that of sequencing,which indicated that the expression of DEGs was more reliable. It might provide a basis for further excavation of regulatory genes and functional genes,which are associated with the adaptability of Cynodon dactylon in flooding.