Conserved miR164-targeted NAC genes negatively regulate drought resistance in rice.
Conserved miR164-targeted NAC genes negatively regulate drought resistance in rice.
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DOI：
10.1093/jxb/eru072
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发表时间：
2014-05
影响因子：
6.9
通讯作者：
Xiong L
中科院分区：
文献类型：
--
作者：
Fang Y;Xie K;Xiong L
miR 164在水稻生殖生长期转录激活了6个NAC转录因子基因，对水稻生殖生长期的耐旱性起负调控作用。microRNA是一大类约22 nt的内源性小RNA，主要通过靶向mRNA进行转录后抑制而成为重要的调节因子。先前的研究表明，拟南芥中的miR 164家族由三个成员组成，其指导五个NAC基因的mRNA的切割以调节发育过程。然而，miR 164靶向的NAC基因在作物中的功能很难破译。在这项研究中，6 miR 164靶向NAC基因（OMTN 1-OMTN 6）在水稻中的保守特征进行了描述，并提供证据，其中4个赋予抗旱负调控作用。OMTN蛋白具有典型NAC转录因子的特征。OMTN基因的miR 164识别位点在水稻种质中高度保守。识别位点的缺失削弱了反式激活活性，表明保守的识别位点在维持OMTN蛋白的功能中起着至关重要的作用。水稻OMTN基因对非生物胁迫具有响应性，并表现出不同的时空表达模式。在水稻中过量表达OMTN 2、OMTN 3、OMTN 4和OMTN 6对生殖阶段的抗旱性产生负面影响。在OMTN 2-、OMTN 3-、OMTN 4-和OMTN 6-过表达的植物中，与应激反应、发育和代谢相关的许多基因的表达被改变。在OMTN过表达的植株中，大多数上调的基因在干旱胁迫下下调。这些结果表明，保守的miR 164靶向NAC基因可能是水稻耐旱性的负调控因子，除了它们在发育中的作用。
Six NAC transcription factor genes were found to be targeted by miR164 at a highly conserved region for transactivation activity and to regulate drought tolerance negatively at the reproductive stage in rice. MicroRNAs constitute a large group of endogenous small RNAs of ~22 nt that emerge as vital regulators, mainly by targeting mRNAs for post-transcriptional repression. Previous studies have revealed that the miR164 family in Arabidopsis is comprised of three members which guide the cleavage of the mRNAs of five NAC genes to modulate developmental processes. However, the functions of the miR164-targeted NAC genes in crops are poorly deciphered. In this study, the conserved features of six miR164-targeted NAC genes (OMTN1–OMTN6) in rice are described, and evidence is provided that four of them confer a negative regulatory role in drought resistance. OMTN proteins have the characteristics of typical NAC transcriptional factors. The miR164 recognition sites of the OMTN genes are highly conserved in rice germplasms. Deletion of the recognition sites impaired the transactivation activity, indicating that the conserved recognition sites play a crucial role in maintaining the function of the OMTN proteins. The OMTN genes were responsive to abiotic stresses, and showed diverse spatio-temporal expression patterns in rice. Overexpression of OMTN2, OMTN3, OMTN4, and OMTN6 in rice led to negative effects on drought resistance at the reproductive stage. The expression of numerous genes related to stress response, development, and metabolism was altered in OMTN2-, OMTN3-, OMTN4-, and OMTN6-overexpressing plants. Most of the up-regulated genes in the OMTN-overexpressing plants were down-regulated by drought stress. The results suggest that the conserved miR164-targeted NAC genes may be negative regulators of drought tolerance in rice, in addition to their reported roles in development.
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影响因子：
4.9
作者：
Decreux, A;Messiaen, J
通讯作者：
Messiaen, J
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DOI：
10.1016/j.bbagrm.2011.05.001
发表时间：
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