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

CLC Number: 

• S435.13