基于亲环素信号途径调控水稻侧根生长发育的转录组分析

水稻(Oryza sativa)亲环素编码基因OsCYP2催化生长素响应蛋白Aux/IAA顺反异构后被26S蛋白酶体降解从而调控侧根生长发育。以水稻品种‘爱知旭’OsCYP2-RNAi株系和野生型为试验材料,进行转录组测序分析,共获得70850697条有效序列,利用TMAP软件将序列比对到水稻品种‘日本晴’参考基因的比例为83.80%~85.04%。基因表达定量分析发现,干扰株系与野生型相比共有3158个差异表达基因(differentially expressed genes,DEGs)(1891个基因上调表达,1267个基因下调表达)。对差异表达基因GO功能注释后进行分类统计发现,生物学途径主要集中在代谢和细胞方面;在细胞组分方面,细胞器合成相关的重要组分差异表达基因较多;而分子功能类群中,差异表达基因主要富集在蛋白结合和催化活性方面,这也反映了OsCYP2作为分子伴侣具有PPIase活性的生物学功能。筛选11个参与侧根生长发育的差异表达基因进行qRT-PCR分析验证转录组测序结果,其中,9个下调差异表达基因主要与蛋白、核酸结合和酶活性等相关,表明基于OsCYP2响应生长素信号途径的下游调控侧根生长发育基因可能受到了抑制。研究结果将为进一步挖掘新的调控基因提供参考。

Seminal, adventitious and lateral root growth and physiological responses in rice to upland conditions

Understanding the growth and physiological responses of rice to upland conditions would be helpful for designing treatments to improve the tolerance of rice under a rainfed system. The objective of this study was to investigate the initiation,elongation and membrane stability of seminal, lateral and adventitious roots of upland rice after 9 d upland condition treatment. Compared with control roots under waterlogged conditions, upland water deficiency conditions favor seminal and lateral root growth over adventitious root growth by accelerating seminal root elongation, promoting lateral root initiation and elongation, and reducing the elongation and number of adventitious roots. Enhanced total root number and length resulted in increase of total root dry weight and thereby increasing the root to shoot ratio. Organic compound leakage from seminal root tips and adventitious roots increased progressively to some extent with upland culture duration, while significant increases in seminal root tips were the consequence of loss of membrane integrity caused by the upland condition enhanced growth.