H2S位于H2O2下游介导葡萄抗霜霉病过程

 以霜霉病抗性葡萄品种左优红和感病品种霞多丽为材料,研究硫化氢(H₂S)在葡萄应答霜霉病过程中的作用及其与过氧化氢(H₂O₂)的相互关系。结果表明,接种霜霉病菌后,抗性品种左优红和感病品种霞多丽叶片均出现H₂S含量的猝发、H₂S合成酶基因表达量增加、抗病相关蛋白多酚氧化酶(PPO)和β-1,3葡聚糖酶(Glu)活性显著升高现象;且H₂S清除剂次牛磺酸(HT)可以显著抑制霜霉病菌诱导的PPO和Glu活性升高,并导致葡萄的感病率和病情指数显著升高;同时外源H₂S可降低两个葡萄品种的感病率和病情指数。说明,H₂S是参与葡萄抗霜霉病过程的新的信号物质。受霜霉病菌侵染后,葡萄叶片H₂O₂含量猝发早于H₂S,并且H₂O₂清除剂抗坏血酸(AsA)可显著抑制霜霉病菌所诱导的H₂S含量的上升,而H₂S清除剂HT对霜霉病菌诱导的H₂O₂含量变化影响不显著,推测,H₂S作用于H₂O₂的下游参与葡萄抵御霜霉病过程。

H2S acts downstream of H2O2 in the regulation of grapevine resistance to Plasmopara viticola

By using two grape cultivars, the resistant Zuoyouhong and the susceptible Chardonnay to Plasmopara viticola, the role of hydrogen sulfide (H₂S) in grape resistance to P. viticola and the relationship between hydrogen sulfide (H₂S) and hydrogen peroxide (H₂O₂) were studied. The results showed that the P. viticola infection induced the H₂S bursts, the increase of L-/D-CDes expression and the enhanced polyphenol oxidase (PPO) and glucanase (Glu) activities in the leaves of Zuoyouhong and Chardonnay. In contrast, the H₂S scavenger hypotaurine (HT) depressed the P. viticola - induced PPO and Glu activities, and elevated colonization frequency and index of P. viticola in Zuoyouhong and Chardonnay. Meanwhile, the exogenous application of H₂S decreased the colonization frequency and index of P. viticola in the two grape cultivars. These results indicated that H₂S played a role in the regulation of grape resistance to P. viticola as a signal molecule. Application of the NADPH oxidase inhibitor dibenziodolium (DPI) and the cell wall peroxidase inhibitor salicylhydroxamic acid (SHAM) significantly suppressed the P. viticola - induced the increase of H₂O₂, it suggested that the NADPH oxidase and the cell wall peroxidase pathways were the important resource of H₂O₂. Based on the observations of the H₂O₂ burst appeared earlier than H₂S in the leaves of grape infected by P. viticola, and the AsA depressed the P. viticola - induced H₂S increase, and the HT had no significant effect on the H₂O₂, it was concluded that H₂S acted functions downstream of H₂O₂ in mediating grape resistance to P. viticola.