2017年12月13日Plant Cell在线文章，该文章为中科院东北地理与农业生态研究所大豆分子设计育种重点实验室卜庆云课题组发表，文章揭示水稻中DHS 可以通过降解ROC4来负调控角质层蜡的生物合成，这为水稻抗旱品种的设计育种提供了基础。

原题目为：

The E3 Ligase DROUGHT HYPERSENSITIVE Negatively Regulates Cuticular Wax Biosynthesis by Promoting the Degradation of Transcription Factor ROC4 in Rice

角质层蜡在保护植物免受环境压力（特别是干旱胁迫）方面起着至关重要的作用。涉及蜡生物合成的许多编码酶和转录因子的基因已经被鉴定了，但是其翻译后调控机制仍知之甚少。这里，我们阐释了一个RING类型的蛋白质DHS，它是水稻蜡生物合成的关键调节子。与野生型相比，DHS过表达植物中的角质层蜡含量显著减少，而dhs突变体中的蜡含量增加，这导致对干旱胁迫相反的响应。DHS表现出E3泛素连接酶活性并与蛋白ROC4相互作用。 ROC4过表达植物和roc4突变体的分析表明，ROC4正调控角质层蜡生物合成和干旱胁迫响应。ROC4在体内被泛素化并且受到泛素/26S蛋白酶体（UPS）介导的降解。DHS促进ROC4降解，但在dhs突变体中延迟。ROC4作用于DHS的下游，Os-BDG是DHS-ROC4级联的直接下游靶标。这些结果表明DHS通过促进ROC4的降解来负调控蜡的生物合成，并且提示DHS和ROC4是耐旱水稻栽培品种工程的有价值的靶标。

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 to 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 (UPS)-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.

每日一词

cuticular

英[kju:'tɪkjʊlə]

美[kju:'tɪkjʊlə]

adj. 表皮的;角质层的

[例句]Skin atrophy affects cuticular, derma and subcutaneous tissue.

皮肤萎缩波及表皮、真皮和皮下组织。

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