Department of Crop Production and Plant Breeding, Shiraz University, Shiraz, Iran.
Department of Plant Pathology, The Ohio State University, OH, 43210, USA.
Plant Physiol Biochem. 2021 Apr;161:248-258. doi: 10.1016/j.plaphy.2021.02.016. Epub 2021 Feb 20.
Co-occurrence of abiotic stresses, especially drought and salinity, is a natural phenomenon in field conditions and is worse for crop production than any single stress. Nowadays, rigorous methods of meta-analysis and systems biology have made it possible to perform cross-study comparisons of single stress experiments, which can uncover main overlapping mechanisms underlying tolerance to combined stress. In this study, a meta-analysis of RNA-Seq data was conducted to obtain the overlapping gene network of drought and salinity stresses in barley (Hordeum vulgare L.), which identified Rubisco activase A (RcaA) as a hub gene in the dual-stress response. Thereafter, a greenhouse experiment was carried out using two barley genotypes with different abiotic stress tolerance and evaluated several physiochemical properties as well as the expression profile and protein activity of RcaA. Finally, machine learning analysis was applied to uncover relationships among combined stress tolerance and evaluated properties. We identified 441 genes which were differentially expressed under both drought and salinity stress. Results revealed that the photosynthesis pathway and, in particular, the RcaA gene are major components of the dual-stress responsive transcriptome. Comparative physiochemical and molecular evaluations further confirmed that enhanced photosynthesis capability, mainly through regulation of RcaA expression and activity as well as accumulation of proline content, have a significant association with combined drought and salinity stress tolerance in barley. Overall, our results clarify the importance of RcaA in combined stress tolerance and may provide new insights for future investigations.
非生物胁迫（如干旱和盐胁迫）的共同发生是田间条件下的一种自然现象，对作物生产的危害甚于任何单一胁迫。如今，严格的荟萃分析和系统生物学方法已经使得对单一胁迫实验进行跨研究比较成为可能，这可以揭示耐受复合胁迫的主要重叠机制。在这项研究中，对大麦（Hordeum vulgare L.）的 RNA-Seq 数据进行了荟萃分析，以获得干旱和盐胁迫的重叠基因网络，该网络确定 Rubisco 激活酶 A（RcaA）是双胁迫反应中的枢纽基因。此后，利用具有不同非生物胁迫耐受性的两个大麦基因型进行了温室实验，并评估了几种生理化学特性以及 RcaA 的表达谱和蛋白活性。最后，应用机器学习分析揭示了复合胁迫耐受性与评估特性之间的关系。我们鉴定了 441 个在干旱和盐胁迫下均差异表达的基因。结果表明，光合作用途径，特别是 RcaA 基因，是双胁迫响应转录组的主要组成部分。比较生理化学和分子评估进一步证实，增强的光合作用能力，主要通过调节 RcaA 的表达和活性以及脯氨酸含量的积累，与大麦对干旱和盐胁迫的综合耐受性有显著关联。总的来说，我们的结果阐明了 RcaA 在复合胁迫耐受性中的重要性，并可能为未来的研究提供新的见解。
