NO和H_2O_2在玉米抗弯孢菌侵染中的生理作用机制

Regulation Mechanisms of NO and H_2O_2 in Maize Against Curvularia lunata

为了明确一氧化氮(NO)和过氧化氢(H2O2)与玉米弯孢菌叶斑病抗性的关系,及作为信号分子调控玉米抵御弯孢菌感染过程中的生理机制。以对玉米弯孢菌叶斑病具有不同抗性的3个玉米种质478、齐319、农大108为试材,外源施用硝普钠(SNP)、2-4,4,5,5-苯-四甲基咪唑-1-氧-3-氧化物(c PTIO)、过氧化氢(H2O2)、抗坏血酸(As A),和接种玉米弯孢病菌,比较植株病情指数、NO和H2O2含量及寄主防御酶活性的变化。结果表明:外施一定浓度的NO供体硝普钠(SNP)和H2O2均可减缓玉米弯孢叶斑病菌侵染进程,降低感病率和平均病情指数,并且能够不同程度地提高植株防御酶活性,尤其抗性弱的玉米种质478植株内过氧化物酶(POD)、过氧化氢酶(CAT)、苯丙氨酸解氨酶(PAL)、超氧化物歧化酶(SOD)和β-1,3-葡聚糖酶(Glu)的活性,诱发了玉米过敏性坏死反应;接种玉米弯孢菌后3个玉米种质叶片中NO和H2O2含量均有猝发现象,而NO和H2O2的清除剂c PTIO和As A在一定程度上能够提高玉米植株感病率和病情指数。NO和H2O2是玉米弯孢菌叶斑病抗病的重要信号分子,可提高POD、CAT、SOD、PAL和Glu病程相关蛋白活性,进而增强玉米对弯孢菌的抗性。

In order to determine the physiological mechanisms of NO and H2O2 in the regulation of maize against Curvularia lunata infection. Three maize germplasm 478,Qi319 and Nongda 108 with different resistant to C.lunata were exogenously treated with sodium nitroprusside（ SNP）,2-（ 4-Carboxyphenyl-） 4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide potassium salt（ c PTIO）,hydrogen peroxide（ H2O2）,ascorbic acid（ ASA） and inoculated with C. lunata,then the disease index,NO or H2O2 content,and different defense enzymes activity were analyzed.The results indicated that,exogenously treated with NO donor sodium nitroprusside（ SNP） or H2O2 could slow down the process of C. lunata,reduce the infection rate and the average disease index of the plants,and increase peroxidase（ POD）,catalase（ CAT）,phenylalanine ammonia lyase（ PAL）,superoxide dismutase（ SOD） and β-1,3-glucanase activity in maize germplasm 478 plants which have a weak resistance to the pathogen,thus induced a hypersensitive reaction in the maize plants; after inoculation with C. lunata,NO or H2O2 content were burst in the leaves of the three maize germplasms,while the scavenger c PTIO and As A of NO and H2O2 could improve the maize infection rate and disease index. Both NO and H2O2 are important signals in maize plants,which could improve pathogenesis-related proteins including POD,CAT,SOD,PAL and β-1,3-glucanase activity,and thus enhance the maize resistance against C. lunat.