Roles Of Oxalic Acid On The Interaction Between Tomato And Botrytis Cinereaand Experssion Of Oxalate Oxidase Gene

Gray mold is the most important disease in tomato;its control is mainly dependent on chemical pesticides currently.Using chemical pesticides largely has made pathogenic drug resistance,the pesticide residue and environmental pollution became the main problems.The study showed that the pathogenic factor oxalic acid could be produced in the process of infecting plants by Botrytis cinerea.In this experiment,we discussed if calcium chloride and dipotassium hydrogen phosphate influenced the pathogenicity of the pathogen by neutralizing oxalic acid,and effects of different pH on the growth and development of B.cinerea.In addition,the incidence of tomato plants with different concentrations of oxalic acid and the changes of the expression of oxalate oxidase gene(OXO)were analyzed,which laid the foundation for the prevention and control of gray mold of tomato.The main results are as follows:1.The inhibitory effect of calcium chloride was detected by the drug-containing plate assay and its disease incidence on the leaves in vitro was investigated.The results showed that different concentrations of calcium chloride had no significant inhibitory effect on the growth of the B.cinerea,but the incidence of tomato gray mold in the detached leaves was reduced by 57.91%.2.The antagonism effect of potassium phosphate dibasic on B.cinerea was investigated by the way described above.The results showed that B.cinerea mycelial growth was completely inhibited in the drug-containing plate with 0.20 mol/L potassium phosphate dibasic;the incidence of gray mold in the detached leaves was reduced by 60.88%.3.The effects of pH on medium B.cinerea growth and virulence of B.cinerea were detected by drug-containing plate methods.The results showed that the different of the medium growth of the two strains caused by pH was not obvious;only when the pH equals to 6,both the virulence of B05.10 and T4 were enhanced compared with the control.4.Treating the tomato leaves with different concentrations of oxalic acid and then detecting the changes of disease incidence.The results showed that treatment with low concentrations of oxalic acid could reduce the disease severity,while high concentration of oxalic acid increased the tomato grey mould disease.5.Tomato leaves treated with different concentrations of oxalic acid,and then oxalate oxidase gene(OXO)and Germin gene expression profiles were analyzed by qRT-PCR.Oxalate oxidase(OXO)gene expression and Germin were first raised and then down after treated tomato plants by Oxalic acid.The oxalate oxidase gene and Germin gene showed the highest expression profile in 48 h,2.75 times and 19.00 times relative to 0 h respectively,when spraying leaves with low concentrations of oxalic acid.Unlike to the low concentration,the expression of oxalate oxidase gene and Germin gene in 48 h,0.50 times and 2.00 times relative to 0h respectively after treating with high concentration of oxalic acid.Oxalate can be degradated by Oxalate oxidase wheat sprouting prime,Taken together,oxalate oxidase(OXO)and Germin genes may play a role in tomato resistance to B.cinerea infection.6.qRT-PCR analysis was used to study the expression profiles of oxalate oxidase(OXO)and Germin gene in tomato leaves inoculated with B05.10 and T4 respectively.The results showed that the strength of the inoculated genes are upregulated,but the expression levels of T4 weakly pathogenic strains after inoculation oxalate oxidase gene in bacteria stronger than height.As showed in the results,Inoculation with the weaker strain T4,the expression of oxalate oxidase gene in tomato leaves has two peaks 24 h and 72 h,with 3.00 times and 2.95 times transcription profile compare with 0h.The expression of the Germin gene was highest with 10.50 times compare with 0h.strong virulence strain B05.10 infected tomato leaves,the transcription of oxalate oxidase gene and reached the peak at 72 h after inoculation and it was 2.40 times compare with 0h;the Germin gene expression reached the peak at 96 h and it was 13.00 times compare with 0h.Further confirmed the oxalate oxidase play a role in tomato plants to B.cinerea resistance.