Wu Guoxiu, Niu Xuxu, Chen Jiahui, Wu Changjiang, Li Yang, Li Yanman, Cui Dandan, He Xueying, Wang Fan, Li Shengli
College of Horticulture, Henan Agricultural University, Zhengzhou 450046, China.
Henan Provincial Facility Horticulture Engineering Technology Research Center, Zhengzhou 450046, China.
Antioxidants (Basel). 2024 Mar 6;13(3):323. doi: 10.3390/antiox13030323.
Tomato is the vegetable with the largest greenhouse area in China, and low temperature is one of the main factors affecting tomato growth, yield, and quality. Hydrogen sulfide (HS) plays an important role in regulating plant chilling tolerance, but its downstream cascade reaction and mechanism remain unclear. Mitogen-activated protein kinases (MAPK/MPKs) are closely related to a variety of signaling substances in stress signal transmission. However, whether HS is related to the MPK cascade pathway in response to low-temperature stress is rarely reported. In this study, NaHS treatment significantly decreased the electrolyte leakage (EL), superoxide anion (O) production rate, and hydrogen peroxide (HO) content of seedlings at low temperatures. In addition, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were obviously increased; and the photochemical efficiency of PSII (Fv/Fm) was enhanced with treatment with NaHS, indicating that NaHS improved the seedlings' cold tolerance by alleviating the degree of membrane lipid peroxidation and oxidative damage. However, HS scavenger hypotaurine (HT) treatment showed the opposite effect. We found that HS content, L-cysteine desulfhydrase (LCD) activity, and mRNA expression were increased by chilling stress but reduced by MPK inhibitor PD98059; PD98059 reversed the alleviating effect of HS via increasing the EL and HO contents. The expression levels of - at low temperatures showed that was significantly induced by exogenous NaHS and showed a trend of first increasing and then decreasing, while the expression level of in HT-treated seedlings was lower than that of the control. After was silenced by virus-induced gene silencing, the HS-induced upregulation of C-repeat-Binding Factor (CBF1), inducer of CBF expression 1 (ICE1), respiratory burst oxidase homologs (RBOH1, RBOH2) at low temperatures disappeared, and tomato cold tolerance decreased. In conclusion, HS improves the cold tolerance of tomato plants by increasing the activity of antioxidant enzymes and reducing reactive oxygen species (ROS) accumulation and membrane lipid peroxidation. MPK4 may act as a downstream signaling molecule in this process.
番茄是中国设施栽培面积最大的蔬菜，低温是影响番茄生长、产量和品质的主要因素之一。硫化氢（H₂S）在调节植物耐冷性方面发挥着重要作用，但其下游级联反应和机制尚不清楚。丝裂原活化蛋白激酶（MAPK/MPKs）在应激信号传递中与多种信号物质密切相关。然而，H₂S是否与响应低温胁迫的MPK级联途径相关鲜有报道。本研究中，NaHS处理显著降低了低温下幼苗的电解质渗漏率（EL）、超氧阴离子（O₂⁻）产生速率和过氧化氢（H₂O₂）含量。此外，超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）的活性明显增加；用NaHS处理后PSII的光化学效率（Fv/Fm）提高，表明NaHS通过减轻膜脂过氧化程度和氧化损伤来提高幼苗的耐寒性。然而，H₂S清除剂次牛磺酸（HT）处理则表现出相反的效果。我们发现，低温胁迫会增加H₂S含量、L-半胱氨酸脱硫酶（LCD）活性和mRNA表达，但MPK抑制剂PD98059会降低这些指标；PD98059通过增加EL和H₂O₂含量逆转了H₂S的缓解作用。低温下相关基因的表达水平表明，外源NaHS显著诱导了该基因表达，呈现先升高后降低的趋势，而HT处理的幼苗中该基因的表达水平低于对照。通过病毒诱导基因沉默使该基因沉默后，低温下H₂S诱导的C-重复结合因子（CBF1）、CBF表达诱导因子1（ICE1）、呼吸爆发氧化酶同源物（RBOH1、RBOH2）上调消失，番茄耐寒性降低。综上所述，H₂S通过增加抗氧化酶活性、减少活性氧（ROS）积累和膜脂过氧化来提高番茄植株的耐寒性。MPK4可能在此过程中作为下游信号分子发挥作用。
