Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany.
Int J Mol Sci. 2021 Sep 28;22(19):10451. doi: 10.3390/ijms221910451.
High night temperatures (HNT) affect rice yield in the field and induce chlorosis symptoms in leaves in controlled chamber experiments. However, little is known about molecular changes in leaf segments under these conditions. Transcript and metabolite profiling were performed for leaf segments of six rice cultivars with different HNT sensitivity. The metabolite profile of the sheath revealed a lower metabolite abundance compared to segments of the leaf blade. Furthermore, pre-adaptation to stress under control conditions was detected in the sheath, whereas this segment was only slightly affected by HNT. No unique significant transcriptomic changes were observed in the leaf base, including the basal growth zone at HNT conditions. Instead, selected metabolites showed correlations with HNT sensitivity in the base. The middle part and the tip were most highly affected by HNT in sensitive cultivars on the transcriptomic level with higher expression of jasmonic acid signaling related genes, genes encoding enzymes involved in flavonoid metabolism and a gene encoding galactinol synthase. In addition, gene expression of expansins known to improve stress tolerance increased in tolerant and sensitive cultivars. The investigation of the different leaf segments indicated highly segment specific responses to HNT. Molecular key players for HNT sensitivity were identified.
高温夜（HNT）会影响田间水稻产量，并在受控室实验中诱导叶片出现黄化症状。然而，对于这些条件下叶片片段的分子变化知之甚少。对六个具有不同 HNT 敏感性的水稻品种的叶片片段进行了转录组和代谢物分析。与叶片片段相比，鞘的代谢物丰度较低。此外，在对照条件下检测到鞘的应激前适应，而该片段仅受到 HNT 的轻微影响。在叶片基部（包括 HNT 条件下的基部生长区）未观察到独特的显著转录组变化。相反，在 HNT 敏感品种的基部，选择的代谢物与 HNT 敏感性呈相关性。在敏感品种中，中部和叶尖在转录组水平上受 HNT 的影响最大，与茉莉酸信号转导相关基因、参与类黄酮代谢的酶基因和半乳糖醇合酶基因的表达增加。此外，已知可提高应激耐受性的扩张蛋白的基因表达在耐受和敏感品种中增加。对不同叶片片段的研究表明，对 HNT 的反应具有高度的片段特异性。确定了 HNT 敏感性的分子关键因素。
