Knockdown of Rice MicroRNA166 Confers Drought Resistance by Causing Leaf Rolling and Altering Stem Xylem Development1
Knockdown of Rice MicroRNA166 Confers Drought Resistance by Causing Leaf Rolling and Altering Stem Xylem Development1
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DOI：
10.1104/pp.17.01432
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发表时间：
2018-01
期刊：
影响因子：
7.4
通讯作者：
Jinshan Zhang;Hui Zhang;A. Srivastava;Yujie Pan;Jinjuan Bai;Jingjing Fang;Huazhong Shi;Jian‐Kang Zhu
中科院分区：
文献类型：
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作者：
Jinshan Zhang;Hui Zhang;A. Srivastava;Yujie Pan;Jinjuan Bai;Jingjing Fang;Huazhong Shi;Jian‐Kang Zhu
敲除microRNA166通过降低茎水传导率和降低叶片蒸腾速率来提高水稻的抗旱性。MicroRNA是一种19 - 22个核苷酸的小非编码RNA，与非生物胁迫反应有关。在这项研究中，我们发现，敲低microRNA166，使用短串联靶模拟（STTM）系统，导致形态变化，赋予水稻（水稻）抗旱性。通过对水稻中miRNA敲低株系的大规模筛选，我们鉴定了miR166敲低株系（STTM166）;这些植物表现出卷叶表型，这通常由干旱胁迫下的水稻植物表现。STTM166水稻植株的叶片具有较小的泡状细胞和异常的厚壁细胞，可能导致卷叶表型。STTM 166植物具有降低的气孔导度，并且显示出降低的蒸腾速率。STTM166品系还表现出改变的茎木质部和降低的导水率，这可能是由于木质部导管直径减小。分子生物学分析表明，HD-Zip III基因家族成员OsHB4（homeodomaincontainingprotein4）是miR166的主要作用靶基因，并且过量表达miR166抗性OsHB4的水稻植株与STTM166植株相似，具有卷叶和更强的抗旱性。miR166-OsHB4的下游基因是多糖合成相关基因，可能与细胞壁形成和血管发育有关。我们的研究结果表明，水稻的抗旱性可以通过操纵miRNAs来提高，这会导致发育变化，如叶片卷曲和木质部直径减小，这模拟了植物对缺水胁迫的自然反应。
Knockdown of microRNA166 increases drought resistance in rice via decreased stem water conductivity and reduced leaf transpiration rates. MicroRNAs are 19- to 22-nucleotide small noncoding RNAs that have been implicated in abiotic stress responses. In this study, we found that knockdown of microRNA166, using the Short Tandem Target Mimic (STTM) system, resulted in morphological changes that confer drought resistance in rice (Oryza sativa). From a large-scale screen for miRNA knockdown lines in rice, we identified miR166 knockdown lines (STTM166); these plants exhibit a rolled-leaf phenotype, which is normally displayed by rice plants under drought stress. The leaves of STTM166 rice plants had smaller bulliform cells and abnormal sclerenchymatous cells, likely causing the rolled-leaf phenotype. The STTM166 plants had reduced stomatal conductance and showed decreased transpiration rates. The STTM166 lines also exhibited altered stem xylem and decreased hydraulic conductivity, likely due to the reduced diameter of the xylem vessels. Molecular analyses identified rice HOMEODOMAIN CONTAINING PROTEIN4 (OsHB4), a member of HD-Zip III gene family, as a major target of miR166; moreover, rice plants overexpressing a miR166-resistant form of OsHB4 resembled the STTM166 plants, including leaf rolling and higher drought resistance. The genes downstream of miR166-OsHB4 consisted of polysaccharide synthesis-related genes that may contribute to cell wall formation and vascular development. Our results suggest that drought resistance in rice can be increased by manipulating miRNAs, which leads to developmental changes, such as leaf rolling and reduced diameter of the xylem, that mimic plants’ natural responses to water-deficit stress.