College of Life Sciences, Northwest Agriculture & Forestry University, 712100, Yangling, China.
Cangzhou Central Hospital, 061000 Cangzhou, China.
Phytochemistry. 2021 Jan;181:112582. doi: 10.1016/j.phytochem.2020.112582. Epub 2020 Nov 24.
Salinity is a major cause of crop losses worldwide. Acetylcholine (ACh) can ameliorate the adverse effects of abiotic stresses on plant growth, including salinity stress; however, the underlying molecular mechanisms of this process are unclear. Here, seedlings of Nicotiana benthamiana grown under normal conditions or exposed to 150 mmol L NaCl salinity stress were then treated with a root application of 10 μM ACh. Exogenous ACh application resulted in the downregulation of the activity of the antioxidant enzymes, ascorbate peroxidase, and catalase. ACh-treated plants had lower levels of reactive oxygen species, including the superoxide anion radical and hydrogen peroxide. Transcriptome analysis indicated that ACh treatment under salt stress promoted the differential expression of 658 genes in leaves of N. benthamiana (527 were upregulated and 131 were downregulated). Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses revealed that exogenous ACh application was associated with a substantial increase in the transcripts of genes related to cell wall peroxidases, xyloglucan endotransglucosylases or hydrolases, and expansins, indicating that ACh activates cell wall biosynthesis in salt-stressed plants. ACh also enhanced the expression of genes associated with the auxin, gibberellin, brassinosteroid, and salicylic acid signalling pathways, indicating that ACh induces the activation of these pathways under salt stress. Collectively, these findings indicate that ACh-induced salt tolerance in N. benthamiana seedlings is mediated by the inhibition of antioxidant enzymes, activation of cell wall biosynthesis, and hormone signalling pathways. Stress-induced genes involved in osmotic regulation and oxidation resistance were induced by ACh under salt stress. The genes whose transcript levels were elevated by ACh treatment in salt-stressed N. benthamiana could be used as molecular markers of the physiological status of plants under salt stress.
盐度是全球作物减产的主要原因。乙酰胆碱（ACh）可以减轻非生物胁迫对植物生长的不利影响，包括盐胁迫；然而，这一过程的潜在分子机制尚不清楚。在这里，在正常条件下生长或暴露于 150mmol/L NaCl 盐胁迫下的 Nicotiana benthamiana 幼苗然后用 10μM ACh 进行根部处理。外源性 ACh 处理导致抗氧化酶（抗坏血酸过氧化物酶和过氧化氢酶）活性下调。ACh 处理的植物具有较低水平的活性氧，包括超氧阴离子自由基和过氧化氢。转录组分析表明，盐胁迫下 ACh 处理促进了 N. benthamiana 叶片中 658 个基因的差异表达（527 个上调，131 个下调）。基因本体富集和京都基因与基因组百科全书通路分析表明，外源性 ACh 处理与与细胞壁过氧化物酶、木葡聚糖内切糖基转移酶或水解酶和扩展蛋白相关基因转录物的大量增加有关，表明 ACh 激活盐胁迫下植物的细胞壁生物合成。ACh 还增强了与生长素、赤霉素、油菜素内酯和水杨酸信号通路相关基因的表达，表明 ACh 在盐胁迫下诱导这些通路的激活。总之，这些发现表明，ACh 诱导 N. benthamiana 幼苗的耐盐性是通过抑制抗氧化酶、激活细胞壁生物合成和激素信号通路来介导的。盐胁迫下，ACh 诱导参与渗透调节和氧化抗性的应激诱导基因的表达。在盐胁迫下，ACh 处理上调的 N. benthamiana 基因的转录水平可作为植物在盐胁迫下生理状态的分子标记。
