Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.
Key Laboratory of Urban Agriculture in Central China, Ministry of Agriculture, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, China.
Plant Mol Biol. 2020 Jun;103(3):287-302. doi: 10.1007/s11103-020-00992-2. Epub 2020 Apr 2.
Volatile components in fresh leaves are involved in the regulation of many stress responses, such as insect damage, fungal infection and high temperature. However, the potential function of volatile components in hyperosmotic response is largely unknown. Here, we found that 7-day hyperosmotic treatment specifically led to the accumulation of (Z)-3-hexen-1-ol, (E)-2-hexenal and methyl salicylate. Transcriptome and qRT-PCR analyses suggested the activation of linolenic acid degradation and methyl salicylate processes. Importantly, exogenous (Z)-3-hexen-1-ol pretreatment dramatically enhanced the hyperosmotic stress tolerance of tea plants and decreased stomatal conductance, whereas (E)-2-hexenal and methyl salicylate pretreatments did not exhibit such a function. qRT-PCR analysis revealed that exogenous ABA induced the expressions of related enzyme genes, and (Z)-3-hexen-1-ol could up-regulate the expressions of many DREB and RD genes. Moreover, exogenous (Z)-3-hexen-1-ol tremendously induced the expressions of specific LOX and ADH genes within 24 h. Taken together, hyperosmotic stress induced (Z)-3-hexen-1-ol accumulation in tea plant via the activation of most LOX, HPL and ADH genes, while (Z)-3-hexen-1-ol could dramatically enhance the hyperosmotic stress tolerance via the decrease of stomatal conductance and MDA, accumulation of ABA and proline, activation of DREB and RD gene expressions, and probably positive feedback regulation of LOXs and ADHs. KEY MESSAGE: Hyperosmotic stress induced (Z)-3-hexen-1-ol accumulation in Camellia sinensis via the up-regulation of most LOX, HPL and ADH genes, while (Z)-3-hexen-1-ol could dramatically enhance the hyperosmotic stress tolerance via the decrease of stomatal conductance, accumulation of proline, activation of DREB and RD gene expressions, and probably positive feedback regulation of LOXs and ADHs.
新鲜叶片中的挥发性成分参与了许多应激反应的调节，如昆虫损伤、真菌感染和高温。然而，挥发性成分在高渗反应中的潜在功能在很大程度上是未知的。在这里，我们发现 7 天的高渗处理特异性地导致了（Z）-3-己烯-1-醇、（E）-2-己烯醛和甲基水杨酸酯的积累。转录组和 qRT-PCR 分析表明亚麻酸降解和甲基水杨酸酯过程的激活。重要的是，外源（Z）-3-己烯-1-醇预处理可显著增强茶树的高渗胁迫耐受性，降低气孔导度，而（E）-2-己烯醛和甲基水杨酸酯预处理则没有表现出这种功能。qRT-PCR 分析表明，外源 ABA 诱导了相关酶基因的表达，（Z）-3-己烯-1-醇可以上调许多 DREB 和 RD 基因的表达。此外，外源（Z）-3-己烯-1-醇在 24 小时内极大地诱导了特定 LOX 和 ADH 基因的表达。综上所述，高渗胁迫通过激活大多数 LOX、HPL 和 ADH 基因诱导茶树中（Z）-3-己烯-1-醇的积累，而（Z）-3-己烯-1-醇通过降低气孔导度、MDA 的积累、ABA 和脯氨酸的积累、DREB 和 RD 基因的激活，以及可能对 LOXs 和 ADHs 的正反馈调节，显著增强了茶树的高渗胁迫耐受性。
