College of Life Sciences, Hebei Normal University, Shijiazhuang, 050024, China.
BMC Plant Biol. 2019 Aug 20;19(1):368. doi: 10.1186/s12870-019-1974-9.
We previously reported the involvement of nitric oxide (NO) and cyclic nucleotide-gated ion channel 6 (CNGC6) in the responses of plants to heat shock (HS) exposure. To elucidate their relationship with heat tolerance in Arabidopsis thaliana, we examined the effects of HS on several groups of seedlings: wild type, cngc6, and cngc6 complementation and overexpression lines.
After HS exposure, the level of NO was lower in cngc6 seedlings than in wild-type seedlings but significantly elevated in the transgenic lines depending on CNGC6 expression level. The treatment of seeds with calcium ions (Ca) enhanced the NO level in Arabidopsis seedlings under HS conditions, whereas treatment with EGTA (a Ca chelator) reduced it, implicating that CNGC6 stimulates the accumulation of NO depending on an increase in cytosolic Ca ([Ca]). This idea was proved by phenotypic observations and thermotolerance testing of transgenic plants overexpressing NIA2 and NOA1, respectively, in a cngc6 background. Western blotting indicated that CNGC6 stimulated the accumulation of HS proteins via NO.
These data indicate that CNGC6 acts upstream of NO in the HS pathway, which improves our insufficient knowledge of the initiation of plant responses to high temerature.
我们之前报道过一氧化氮（NO）和环核苷酸门控离子通道 6（CNGC6）参与植物对热激（HS）暴露的反应。为了阐明它们与拟南芥耐热性的关系，我们研究了 HS 对几组幼苗的影响：野生型、cngc6、cngc6 互补和过表达系。
HS 暴露后，cngc6 幼苗中的 NO 水平低于野生型幼苗，但在依赖于 CNGC6 表达水平的转基因系中显著升高。用钙离子（Ca）处理种子可增强 HS 条件下拟南芥幼苗中的 NO 水平，而用 EGTA（Ca 螯合剂）处理则降低了 NO 水平，表明 CNGC6 依赖于细胞质 Ca（[Ca]）的增加来刺激 NO 的积累。这一观点通过在 cngc6 背景下分别过表达 NIA2 和 NOA1 的转基因植物的表型观察和耐热性测试得到了证实。Western blot 分析表明，CNGC6 通过 NO 刺激 HS 蛋白的积累。
这些数据表明，CNGC6 在 HS 途径中位于 NO 的上游，这增加了我们对植物对高温反应起始的了解。
