摘要： 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(cPTIO)、过氧化氢(H₂O₂)、抗坏血酸(AsA),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cPTIO和AsA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。

关键词: 玉米弯孢菌, NO和H₂O₂, 寄主防御酶, 抗病性生理

Abstract: 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(cPTIO),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 cPTIO and AsA 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.

Key words: Curvularia lunata, NO and H₂O₂, Host defense enzymes, Resistance physiology

中图分类号: 

• S435.13