Laboratory Center of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China.
Institute of Botany, Jiangsu Province and Chinese Academy of Sciences, Nanjing, 210014, China.
Plant Mol Biol. 2019 Nov;101(4-5):439-454. doi: 10.1007/s11103-019-00914-x. Epub 2019 Aug 30.
Our study firstly elaborated the underlying mechanism of endogenous CH-induced abiotic tolerance, along with an alteration of ABA sensitivity by mimicking the endogenous CH production in MtMCR transgenic Arabidopsis. Endogenous methane (CH) production and/or emission have been ubiquitously observed in stressed plants. However, their physiological roles remain unclear. Here, the methyl-coenzyme M reductase gene from Methanobacterium thermoautotrophicum (MtMCR), encoding the enzyme of methanogenesis, was expressed in Arabidopsis thaliana, to mimic the production of endogenous CH. In response to salinity and osmotic stress, MtMCR expression was up-regulated in transgenic plants, resulting in significant increase of endogenous CH levels. Similar results were observed in abscisic acid (ABA) treatment. The functions of endogenous CH were characterized by the changes in plant phenotypes related to stress and ABA sensitivity during the germination and post-germination periods. When challenged with osmotic stress, a reduction in water loss and stomatal closure, were observed. Redox homeostasis was reestablished during osmotic and salinity stress, and ion imbalance was also restored in salinity conditions. The expression of several stress/ABA-responsive genes was up-regulated, and ABA sensitivity, in particularly, was significantly altered in the MtMCR transgenic plants. Together, our genetic study for the first time elaborated the possible mechanism of endogenous CH-enhanced salinity and osmotic tolerance, along with an alteration of ABA sensitivity. These findings thus provided novel cues for understanding the possible roles of endogenous CH in plants.
我们的研究首先阐述了内源性 CH 诱导非生物胁迫耐性的潜在机制，以及通过模拟 MtMCR 转基因拟南芥中内源性 CH 的产生来改变 ABA 敏感性。在胁迫植物中广泛观察到内源性甲烷 (CH) 的产生和/或排放。然而，它们的生理作用仍不清楚。在这里，来自产甲烷菌（Methanobacterium thermoautotrophicum）的甲基辅酶 M 还原酶基因（MtMCR）被表达在拟南芥中，以模拟内源性 CH 的产生。在盐胁迫和渗透胁迫下，转基因植物中 MtMCR 的表达上调，导致内源性 CH 水平显著增加。在 ABA 处理中也观察到了类似的结果。内源性 CH 的功能通过与胁迫和 ABA 敏感性相关的植物表型变化在萌发和萌发后时期来表征。在渗透胁迫下，观察到水分损失减少和气孔关闭。在渗透和盐胁迫期间重新建立了氧化还原稳态，并且在盐胁迫条件下也恢复了离子失衡。几种应激/ABA 响应基因的表达上调，并且 MtMCR 转基因植物中的 ABA 敏感性显著改变。总之，我们的遗传研究首次阐述了内源性 CH 增强盐和渗透胁迫耐性以及改变 ABA 敏感性的可能机制。这些发现为理解内源性 CH 在植物中的可能作用提供了新的线索。
