Increasing evidences highlight the importance of DEAD‐box RNA helicases in plant development and stress responses. In a previous study, we characterized the tomato res mutant (restored cell structure by salinity ), showing chlorosis and development alterations that reverted under salt‐stress conditions. Map‐based cloning demonstrates that RES gene encodes SlDEAD39, a chloroplast‐targeted DEAD‐box RNA helicase. Constitutive expression of SlDEAD39 complements the res mutation, while the silencing lines had a similar phenotype than res mutant, which is also reverted under salinity. Functional analysis of res mutant proved SlDEAD39 is involved in the in vivo processing of the chloroplast, 23S rRNA, at the hidden break‐B site, a feature also supported by in vitro binding experiments of the protein. In addition, our results show that other genes coding for chloroplast‐targeted DEAD‐box proteins are induced by salt‐stress, which might explain the rescue of the res mutant phenotype. Interestingly, salinity restored the phenotype of res adult plants by increasing their sugar content and fruit yield. Together, these results propose an unprecedented role of a DEAD‐box RNA helicase in regulating plant development and stress response through the proper ribosome and chloroplast functioning, which, in turn, represents a potential target to improve salt tolerance in tomato crops.

中文翻译：

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res（通过盐度还原的细胞结构）番茄突变体揭示了DEAD-box RNA解旋酶SlDEAD39在植物发育和盐响应中的作用。

越来越多的证据凸显了DEAD-box RNA解旋酶在植物发育和胁迫响应中的重要性。在先前的研究中，我们表征了番茄res突变体（通过盐度恢复了细胞结构），显示了在盐胁迫条件下恢复的萎黄病和发育变化。基于图谱的克隆表明RES基因编码了以叶绿体为导向的DEAD-box RNA解旋酶SlDEAD39。SlDEAD39的组成型表达与res突变互补，而沉默株的表型与res突变相似，后者在盐度下也可以恢复。资源功能分析该突变体证明SlDEAD39在隐藏的break-B位点参与了叶绿体23S rRNA的体内加工，该功能也受到蛋白质的体外结合实验的支持。此外，我们的结果表明，盐胁迫诱导了其他编码叶绿体靶向DEAD-box蛋白的基因，这可能解释了res突变表型的拯救。有趣的是，盐度恢复的表型水库，增加其糖含量，果实产量成株。总之，这些结果表明，DEAD-box RNA解旋酶通过适当的核糖体和叶绿体功能在调节植物发育和胁迫响应中发挥了前所未有的作用，这反过来又是提高番茄作物耐盐性的潜在目标。