NO和H_2O_2提高葡萄抗霜霉病的生理作用机制

The physiological mechanisms of NO and H_2O_2 in increasing resistances of grapevine to Plasmopara viticola

以对霜霉病具有不同抗性的3个葡萄品种Fredonia、西拉和赤霞珠为材料,研究一氧化氮(NO)和过氧化氢(H2O2)在调控葡萄抵御霜霉病菌感染过程中的生理机制。结果表明:接种葡萄霜霉病菌后3个葡萄品种叶片中NO和H2O2含量均有猝发现象,H2O2猝发早于NO,抗性强的品种Fredonia的变化快而显著;外施一定浓度的NO供体硝普钠(SNP)和H2O2均可减缓霜霉病菌侵染过程,降低感病率和平均病情指数,并且能够不同程度地提高抗性弱的葡萄品种赤霞珠叶片的过氧化物酶(POD)、苯丙氨酸解氨酶(PAL)、β-1,3-葡聚糖酶(Glu)和几丁质酶(Cht)活性,增强葡萄过敏性坏死反应;而NO和H2O2的清除剂2-4,4,5,5-苯-四甲基咪唑-1-氧-3-氧化物(cPTIO)和抗坏血酸(AsA)在一定程度上能够提高感病率和平均病情指数。推测NO和H2O2可以通过提高POD、PAL、Glu和Cht病程相关蛋白活性,进而增强葡萄对霜霉病的抗性。

In order to investigate the roles and mechanisms of nitric oxide（NO） and hydrogen peroxide（H2O2） in the process of grapes against Plasmopara viticola,three grape cultivars（Cabernet Sauvignon,Syrah and Fredonia） with different resistance to P.viticola were used in this study.The results showed that NO and H2O2 burst occurred in the three cultivars inoculated with P.viticola,and H2O2 burst was earlier than NO,the high resistant variety（Fredonia） changed rapidly and significantly.Exogenous NO donor sodium nitroprusside（SNP） and H2O2 could slow down P.viticola infection process,decrease the incidence and the average disease index.At the same time,2-（4-carboxyphenyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxidepotassium salt（cPTIO,a NO scavenger） and ascorbic acid（AsA,a H2O2 scavenger） increased the rate of infection and the average disease index.The activities of POD（peroxidase）,PAL（phenylalanine ammonialyase）,Glu（β-1,3-glucanase） and Cht（chitinase） in Cabernet Sauvignon,a susceptible cultivar,increased at varying degrees when treated with NO and H2O2,it increased the hypersensitive response of Cabernet Sauvignon.The results suggested that the activities of pathogen-associated enzymes（POD,PAL,Glu,and Cht） were induced by NO and H2O2,and thus enhanced the resistance of grape against P.viticola.