The E3 Ligase DROUGHT HYPERSENSITIVE Negatively Regulates Cuticular Wax Biosynthesis by Promoting the Degradation of Transcription Factor ROC4 in Rice
The E3 Ligase DROUGHT HYPERSENSITIVE Negatively Regulates Cuticular Wax Biosynthesis by Promoting the Degradation of Transcription Factor ROC4 in Rice
复制标题
E3 连接酶干旱超敏通过促进水稻转录因子 ROC4 的降解来负调节角质层蜡的生物合成。
DOI：
10.1105/tpc.17.00823
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发表时间：
2018-01-01
期刊：
影响因子：
11.6
通讯作者：
Bu, Qingyun
中科院分区：
文献类型：
--
作者：
Wang, Zhenyu;Tian, Xiaojie;Bu, Qingyun
角质层蜡质在保护植物免受环境胁迫，特别是干旱胁迫中起着至关重要的作用。许多参与蜡生物合成的酶编码基因和转录因子已被确定，但对潜在的翻译后调控机制知之甚少。在这里，我们证明了干旱超敏感（DHS），编码一个真正有趣的新基因（RING）型蛋白，是一个重要的调节器蜡的生物合成在水稻（水稻）。与野生型相比，DHS过表达植株角质层蜡质含量显著降低，而DHS突变体角质层蜡质含量显著增加，这导致了与干旱胁迫相反的反应。DHS表现出E3泛素连接酶活性，并与同源结构域亮氨酸拉链IV蛋白ROC 4相互作用。对ROC 4过表达植株和突变体的分析表明，ROC 4正调控角质层蜡质的生物合成和干旱胁迫反应。ROC 4在体内被泛素化，并受到泛素/26 S蛋白酶体介导的降解。DHS促进ROC 4降解，但在DHS突变体中延迟。ROC 4作用于DHS的下游，Os-BDG是DHS-ROC 4级联的直接下游靶标。这些结果表明DHS通过促进ROC 4的降解来负调节蜡生物合成的机制，并且它们表明DHS和ROC 4是耐旱水稻品种工程化的有价值的靶标。
Cuticular wax plays crucial roles in protecting plants from environmental stresses, particularly drought stress. Many enzyme-encoding genes and transcription factors involved in wax biosynthesis have been identified, but the underlying posttranslational regulatory mechanisms are poorly understood. Here, we demonstrate that DROUGHT HYPERSENSITIVE (DHS), encoding a Really Interesting New Gene (RING)-type protein, is a critical regulator of wax biosynthesis in rice (Oryza sativa). The cuticular wax contents were significantly reduced in DHS overexpression plants but increased in dhs mutants compared with the wild type, which resulted in a response opposite that of drought stress. DHS exhibited E3 ubiquitin ligase activity and interacted with the homeodomain-leucine zipper IV protein ROC4. Analysis of ROC4 overexpression plants and roc4 mutants indicated that ROC4 positively regulates cuticular wax biosynthesis and the drought stress response. ROC4 is ubiquitinated in vivo and subjected to ubiquitin/26S proteasome-mediated degradation. ROC4 degradation was promoted by DHS but delayed in dhs mutants. ROC4 acts downstream of DHS, and Os-BDG is a direct downstream target of the DHS-ROC4 cascade. These results suggest a mechanism whereby DHS negatively regulates wax biosynthesis by promoting the degradation of ROC4, and they suggest that DHS and ROC4 are valuable targets for the engineering of drought-tolerant rice cultivars.