Effects Of Three Chemical Inducing Agents On Resistance To Fusarium Oxysporum F.sp.Melonis In Melon

Fusarium Wilt is an important typical kind of melon disease around,caused by Fusarium oxysporum in melon.The disease in the process of plant growth all can come on,often causes plantlets wilt die.In the recent years,with the expansion of cultivated areas,the damage caused by wilt increase year by year.The common way of prevention and cure is mainly chemical control,which is easy to cause drug resistance and the problem of environmental pollution.Conseuquently,it is urgent to find a more efective and nontoxic prevention and cure measure.In this study, exogenous substances were used to induce melon matherials.Inoculation with Fusarium Wilt,and investigate the incidence of the plants,and screen out of suitable conncetration.In order to find the cause of resistance by exogenous facrors,we analyse the change trend of enzyme activity of PPO and PAL.Analyse the changes of gene expression,include Fom-2 and CHT with real-time quantitative PCR.Control efficacies of extraneous factors against fusarium wilt in melon were investigated.Result indicated that:（1） The three exogenous substances had different effects on the resistance to Fusarium Wilt of melon, in which the effect of salicylic acid and methyl ester methyl ester was the best. 1 mmol/L salicylic acid induced the relative control effect of 50.7% and 45.7% on the Fusarium Wilt of melon; 1.2 mmol/L methyl ester treatment on the relative prevention effect of Melon Wilt was66.7% and 40.3%,which was significantly higher than that of control and Ca²⁺ treatment.（2） The influence of SA,MeJA and Ca in single treatmet on activties of defense enzymes of melon were analyzed, Salicylic acid, methyl ester treatment, melon plant leaf related defense enzyme system polyphenol oxidase（PPO）, phenylalanine ammonia（PAL） activity was on the rise.Result demonstrated that SA,MeJA increased the activities of polyphenol oxidase,phenylalanine ammoialyase of melon.（3） There were changes of Fom-2 gene expression in melon of MR-1.With the passage of events cause by Fusarium Wilt of melon,the expression of gene was on the rise,and overall higher than the control,which was induced by SA and MeJA.The same to the gene in melon of M1-15.（4）There were changes of CHT gene expression in melon of MR-1.With the passage of events cause by Fusarium Wilt of melon,the expression of gene was on the rise,and overall higher than thecontrol,which was induced by SA.The same to the gene in melon of M1-15.