ABSTRACT

An experiment was conducted to examine whether application of sodium nitroprusside (SNP), a donor of NO, can improve thermo-tolerance of strawberry (Fragaria × ananassa) plants through inducing antioxidant system, and up-regulating heat stress transcription factors (HSFs) and heat shock proteins (HSPs) genes. Ventana strawberry plants were exposed to various temperatures (25, 35, and 40°C) for 24 h after pre-treatment with 0, 50, and 100 μM SNP. Heat stress significantly induced malondialdehyde and hydrogen peroxide (H₂O₂) contents, and increased accumulation of proline, whereas reduced relative water content (RWC), leaf chlorophyll fluorescence, and carotenoid content. In addition, heat stress enhanced superoxide dismutase and guaiacol peroxidase activities, increased glutathione and ascorbic acid contents, and reduced catalase and ascorbate peroxidase activities. Pre-treatment with SNP, especially at 100 μM, ameliorated heat injury by controlling the overaccumulation of H₂O₂, reducing lipid peroxidation, improvement of RWC, and increasing the enzymatic and non-enzymatic antioxidants. Transcriptomic profiling analysis showed that the expression of FaTHSFA2a, FaTHSFB1a, HSP70, and HSP90 in SNP pre-treated plants was significantly higher than non-treated plants after 2 h of heat stress at 40°C. These results suggested that NO alleviates heat-induced oxidative damage by modulating antioxidant pathways and fast inducing the expression of heat-stress related genes.

摘要

试验研究了施用NO供体硝普钠（SNP）是否能通过诱导抗氧化系统、上调热应激转录因子（HSFs）和热休克蛋白 ( HSP ) 基因。在用 0、50 和 100 μM SNP 预处理后，将 Ventana 草莓植物暴露在各种温度（25、35 和 40°C）下 24 小时。热应激显着诱导丙二醛和过氧化氢（H ₂ O ₂) 含量，并增加脯氨酸的积累，而降低相对含水量 (RWC)、叶绿素荧光和类胡萝卜素含量。此外，热应激增强了超氧化物歧化酶和愈创木酚过氧化物酶的活性，增加了谷胱甘肽和抗坏血酸的含量，并降低了过氧化氢酶和抗坏血酸过氧化物酶的活性。用 SNP 预处理，特别是在 100 μM 时，通过控制 H ₂ O ₂的过度积累、减少脂质过氧化、改善 RWC 以及增加酶促和非酶促抗氧化剂来改善热损伤。转录组学分析表明FaTHSFA2a、FaTHSFB1a、HSP70和HSP90 的表达在 40°C 下经过 2 小时的热应激后，SNP 预处理植物中的显着高于未处理植物。这些结果表明NO通过调节抗氧化途径和快速诱导热应激相关基因的表达来减轻热诱导的氧化损伤。