Wei Haibin, Chen Chen, Ma Xiaosong, Zhang Yu, Han Jing, Mei Hanwei, Yu Shunwu
Shanghai Agrobiological Gene Center Shanghai, China.
Front Plant Sci. 2017 Mar 29;8:437. doi: 10.3389/fpls.2017.00437. eCollection 2017.
Water deficit caused a serious threat to crops, especially panicle development at reproductive growth phase. We investigated grain yield components and gene expression profiles of panicle among tolerant and sensitive rice in response to drought stress. Panicle morphologies exhibited that secondary branches per panicle were more severely affected as compared to primary branches per panicle. Moreover, grain weight per panicle showed significant decrease for both tolerant and sensitive varieties except for MILT1444. Expression profile analysis revealed that 783 differentially expressed genes (DEGs) were identified to be drought-induced from young panicles in 2 cm length. Hierarchical clustering indicated that 76.8% of DEGs were up-regulated for all six rice varieties, and the percentage of down-regulated genes was higher in sensitive group than tolerant group. Biological process category revealed that the shared Gene Ontology (GO) terms were involved in response to abiotic stimulus and stress, whereas the specific GO terms in tolerant group were identified as regulation of biological quality, homeostatic process, cell growth, anatomical structure morphogenesis and development, and the unique terms in sensitive varieties were identified as lipid metabolic process and secondary metabolic process. Furthermore, the gene-based association analysis narrowed down list of DEGs, and four genes common to all six varieties were selected as candidate for breeders. Together, we found several shared and distinct biological processes between tolerant and sensitive varieties, and candidate stress-responsive genes. These findings provided insight into functional mechanisms regulating drought stress response in panicle development and may also help to crop tolerant improvement.
水分亏缺对作物构成严重威胁，尤其是在生殖生长阶段对穗发育的影响。我们研究了耐旱和敏感水稻品种在干旱胁迫下穗部的产量构成因素和基因表达谱。穗形态表明，与每穗一次枝梗相比，每穗二次枝梗受影响更严重。此外，除MILT1444外，耐旱和敏感品种的每穗粒重均显著下降。表达谱分析显示，从2厘米长的幼穗中鉴定出783个差异表达基因（DEG）为干旱诱导基因。层次聚类表明，所有六个水稻品种中76.8%的DEG上调，敏感组中下调基因的比例高于耐旱组。生物学过程类别显示，共享的基因本体（GO）术语参与对非生物刺激和胁迫的反应，而耐旱组中的特定GO术语被确定为生物质量调控、稳态过程、细胞生长、解剖结构形态发生和发育，敏感品种中的独特术语被确定为脂质代谢过程和次生代谢过程。此外，基于基因的关联分析缩小了DEG列表范围，六个品种共有的四个基因被选为育种候选基因。总之，我们发现了耐旱和敏感品种之间的一些共同和不同的生物学过程以及候选的胁迫响应基因。这些发现为穗发育过程中干旱胁迫响应的功能机制提供了见解，也可能有助于作物耐旱性改良。
