Wang Dong, Qin Baoxiang, Li Xiang, Tang Ding, Zhang Yu'e, Cheng Zhukuan, Xue Yongbiao
State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences and National Center for Plant Gene Research, Beijing, China.
State Key Laboratory of Plant Genomics, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences and National Center for Plant Gene Research, Beijing, China.
PLoS Genet. 2016 Feb 5;12(2):e1005844. doi: 10.1371/journal.pgen.1005844. eCollection 2016 Feb.
Plants have evolved a considerable number of intrinsic tolerance strategies to acclimate to ambient temperature increase. However, their molecular mechanisms remain largely obscure. Here we report a DEAD-box RNA helicase, TOGR1 (Thermotolerant Growth Required1), prerequisite for rice growth themotolerance. Regulated by both temperature and the circadian clock, its expression is tightly coupled to daily temperature fluctuations and its helicase activities directly promoted by temperature increase. Located in the nucleolus and associated with the small subunit (SSU) pre-rRNA processome, TOGR1 maintains a normal rRNA homeostasis at high temperature. Natural variation in its transcript level is positively correlated with plant height and its overexpression significantly improves rice growth under hot conditions. Our findings reveal a novel molecular mechanism of RNA helicase as a key chaperone for rRNA homeostasis required for rice thermotolerant growth and provide a potential strategy to breed heat-tolerant crops by modulating the expression of TOGR1 and its orthologs.
植物已经进化出相当多的内在耐受策略来适应环境温度升高。然而，它们的分子机制在很大程度上仍然不清楚。在这里，我们报道了一种DEAD-box RNA解旋酶TOGR1（耐热生长必需1），它是水稻耐热生长的先决条件。受温度和生物钟的调控，其表达与每日温度波动紧密相关，并且其解旋酶活性直接受温度升高的促进。TOGR1位于核仁中并与小亚基（SSU）前体rRNA加工复合体相关联，在高温下维持正常的rRNA稳态。其转录水平的自然变异与株高呈正相关，并且其过表达显著改善了高温条件下水稻的生长。我们的研究结果揭示了RNA解旋酶作为水稻耐热生长所需rRNA稳态关键伴侣的新分子机制，并提供了一种通过调节TOGR1及其直系同源基因的表达来培育耐热作物的潜在策略。
