Department of Animal, Plant and Soil Science, ARC Centre of Excellence in Plant Energy Biology, La Trobe University, Bundoora, Victoria, 3086, Australia.
Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, 9052, Ghent, Belgium.
Plant J. 2020 Jul;103(1):227-247. doi: 10.1111/tpj.14724. Epub 2020 Apr 10.
Mitochondria have critical functions in the acclimation to abiotic and biotic stresses. Adverse environmental conditions lead to increased demands in energy supply and metabolic intermediates, which are provided by mitochondrial ATP production and the tricarboxylic acid (TCA) cycle. Mitochondria also play a role as stress sensors to adjust nuclear gene expression via retrograde signalling with the transcription factor (TF) ANAC017 and the kinase CDKE1 key components to integrate various signals into this pathway. To determine the importance of mitochondria as sensors of stress and their contribution in the tolerance to adverse growth conditions, a comparative phenotypical, physiological and transcriptomic characterisation of Arabidopsis mitochondrial signalling mutants (cdke1/rao1 and anac017/rao2) and a set of contrasting accessions was performed after applying the complex compound stress of submergence. Our results showed that impaired mitochondrial retrograde signalling leads to increased sensitivity to the stress treatments. The multi-factorial approach identified a network of 702 co-expressed genes, including several WRKY TFs, overlapping in the transcriptional responses in the mitochondrial signalling mutants and stress-sensitive accessions. Functional characterisation of two WRKY TFs (WRKY40 and WRKY45), using both knockout and overexpressing lines, confirmed their role in conferring tolerance to submergence. Together, the results revealed that acclimation to submergence is dependent on mitochondrial retrograde signalling, and underlying transcriptional re-programming is used as an adaptation mechanism.
线粒体在适应非生物和生物胁迫方面具有关键功能。不利的环境条件导致对能量供应和代谢中间产物的需求增加，这些都是由线粒体 ATP 产生和三羧酸（TCA）循环提供的。线粒体还作为应激传感器发挥作用，通过与转录因子（TF）ANAC017 和激酶 CDKE1 的逆行信号转导来调节核基因表达，这些是整合各种信号进入该途径的关键组成部分。为了确定线粒体作为应激传感器的重要性及其在耐受不利生长条件中的贡献，对拟南芥线粒体信号突变体（cdke1/rao1 和 anac017/rao2）和一组对照品系进行了表型、生理和转录组学的比较分析，然后应用了复合同化化合物胁迫进行处理。我们的结果表明，受损的线粒体逆行信号转导导致对胁迫处理的敏感性增加。多因素方法鉴定了一个由 702 个共表达基因组成的网络，其中包括几个 WRKY TF，在线粒体信号突变体和应激敏感品系中的转录响应中重叠。使用敲除和过表达系对两个 WRKY TF（WRKY40 和 WRKY45）进行功能表征，证实了它们在赋予对淹没耐受中的作用。总之，这些结果表明，对淹没的适应依赖于线粒体逆行信号转导，并且潜在的转录重编程被用作适应机制。
