Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China; Department of Plant and Environmental Sciences, Facility of Science, University of Copenhagen, Frederiksberg, 1870, Denmark.
Tea Research Institute, Shandong Academy of Agricultural Sciences, Jinan, 250100, China.
Environ Pollut. 2022 Aug 15;307:119530. doi: 10.1016/j.envpol.2022.119530. Epub 2022 May 27.
Nitric oxide (NO) and ethylene are both important signaling molecules which participate in numerous plant development processes and environmental stress resistance. Here, we investigate whether and how NO interacts with ethylene during the development of endodermal barriers that have major consequences for the apoplastic uptake of cadmium (Cd) in the hyperaccumulator Sedum alfredii. In response to Cd, an increased NO accumulation, while a decrease in ethylene production was observed in the roots of S. alfredii. Exogenous supplementation of NO donor SNP (sodium nitroprusside) decreased the ethylene production in roots, while NO scavenger cPTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) had the opposite effect. The exogenous addition of NO affected the ethylene production through regulating the expression of genes related to ethylene synthesis. However, upon exogenous ethylene addition, roots retained their NO accumulation. The abovementioned results suggest that ethylene is downstream of the NO signaling pathway in S. alfredii. Regardless of Cd, addition of SNP promoted the deposition of endodermal barriers via regulating the genes related to Casparian strips deposition and suberization. Correlation analyses indicate that NO positively modifies the formation of endodermal barriers via the NO-ethylene signaling pathway, Cd-induced NO accumulation interferes with the synthesis of ethylene, leading to a deposition of endodermal barriers in S. alfredii.
一氧化氮（NO）和乙烯都是重要的信号分子，参与植物的许多发育过程和环境胁迫抗性。在这里，我们研究了在参与质外体摄取镉（Cd）的内胚层屏障发育过程中，NO 是否以及如何与乙烯相互作用。在超积累植物东南景天的根中，Cd 处理后观察到 NO 积累增加，而乙烯生成减少。外源 NO 供体 SNP（硝普钠）的添加降低了根中的乙烯生成，而 NO 清除剂 cPTIO（2-（4-羧基苯基）-4,4,5,5-四甲基咪唑啉-1-氧-3-氧化物）则有相反的效果。NO 通过调节与乙烯合成相关的基因的表达来影响乙烯的生成。然而，在外源添加乙烯后，根保留了它们的 NO 积累。上述结果表明，在东南景天中，乙烯是 NO 信号通路的下游。无论是否有 Cd，添加 SNP 通过调节与 Casparian 带沉积和木质素化相关的基因促进内胚层屏障的沉积。相关分析表明，NO 通过 NO-乙烯信号通路正向修饰内胚层屏障的形成，Cd 诱导的 NO 积累干扰乙烯的合成，导致东南景天中内胚层屏障的沉积。
