Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, 150040, China.
Plant Physiol Biochem. 2022 Sep 1;186:40-51. doi: 10.1016/j.plaphy.2022.06.027. Epub 2022 Jul 4.
Although improvement of plant salt tolerance by potassium ions (K) has been widely studied, whether the tolerance is mediated via hormone signaling or antioxidant systems remains to be explored. This study combined plant physiology with transcriptomic techniques to study how K interacts with hormones and antioxidant enzymes to improve plant salt tolerance. Tobacco was used as the test material to study the effects of exogenous potassium application on photosynthetic function, hormone signal transduction, and reactive oxygen species (ROS) production under NaCl stress. The study also evaluated the function of the Ca signaling pathway in salt stress tolerance. Transcriptome data showed that 4413 up-regulated genes and 3743 down-regulated genes were found in tobacco leaves treated with NaCl compared with the control. Compared with NaCl, the down-regulated genes in tobacco leaves were significantly reduced under NaCl + KCL treatment. The results showed that NaCl stress caused oxidative damage to tobacco leaves due to increased superoxide anion (O) content, superoxide dismutase (SOD) dismutates superoxide anion to produce hydrogen peroxide and the accumulation of HO caused by reduced ascorbate peroxidase (APX) and peroxidase (POD) activities. NaCl stress also increased abscisic acid (ABA) content in tobacco leaves, resulting in stomatal closure and reduced photosynthetic capacity. Transcriptome data showed that 5 SOD, 1 POD, 1 CAT, 5 APX, and 3 GPX genes were significantly down-regulated by the NaCl treatment. Contrarily, NaCl + KCl treatment reduced the accumulation of Oand SOD activity but increased POD activity, thereby reducing the accumulation of HO and alleviating oxidative damage. The expression of 2 SOD and 3 APX and 2 GPX genes was significantly higher in NaCl + KCl treatment than that in NaCl treatment. Sufficient K also increased indole acetic acid (IAA) levels in tobacco leaves under NaCl stress but reduced ABA content, promoting stomatal opening and improving the photosynthetic capacity. In conclusion, K can improve plant salt tolerance by alleviating oxidative damage and regulating hormone signal transduction.
虽然钾离子（K）对提高植物耐盐性已被广泛研究，但这种耐盐性是否通过激素信号转导或抗氧化系统介导仍有待探索。本研究结合植物生理学和转录组技术，研究了 K 如何与激素和抗氧化酶相互作用来提高植物耐盐性。本研究以烟草为材料，研究了外源钾应用对 NaCl 胁迫下光合作用功能、激素信号转导和活性氧（ROS）产生的影响。本研究还评估了钙信号通路在耐盐性中的作用。转录组数据显示，与对照相比，NaCl 处理的烟草叶片中发现 4413 个上调基因和 3743 个下调基因。与 NaCl 相比，NaCl+KCL 处理下烟草叶片中的下调基因显著减少。结果表明，由于超氧阴离子（O）含量增加，NaCl 胁迫对烟草叶片造成氧化损伤，超氧化物歧化酶（SOD）将超氧阴离子歧化为过氧化氢，而过氧化氢的积累导致抗坏血酸过氧化物酶（APX）和过氧化物酶（POD）活性降低。NaCl 胁迫还增加了烟草叶片中的脱落酸（ABA）含量，导致气孔关闭和光合作用能力降低。转录组数据显示，5 个 SOD、1 个 POD、1 个 CAT、5 个 APX 和 3 个 GPX 基因在 NaCl 处理下显著下调。相反，NaCl+KCl 处理降低了 O 的积累和 SOD 活性，但增加了 POD 活性，从而减少了 HO 的积累并减轻了氧化损伤。与 NaCl 处理相比，NaCl+KCl 处理中 2 个 SOD 和 3 个 APX 和 2 个 GPX 基因的表达显著增加。充足的 K 还增加了 NaCl 胁迫下烟草叶片中的吲哚乙酸（IAA）水平，但降低了 ABA 含量，促进了气孔开放，提高了光合作用能力。综上所述，K 可以通过减轻氧化损伤和调节激素信号转导来提高植物的耐盐性。
