Effects Of Environment PH On The Pathogenicity Of Citrus Penicillium Digitatum

It’s prone to happen post harvest diseases for citrus fruit in the process of storage,transportation and sale,which causing serious economic losses.There are many kinds of pathogens causing postharvest diseases of citrus fruit,green mold caused by Penicillium digitatum is the most serious.The pH of around the diseased site of the infected fruit will decline,and the rate of fruit lesion expansion will be faster accompanied by that.In this study,we hope to find out the relevant genes which affect Penicillium digitatum regulate the environment pH,in order to provide ideas and theoretical basis for the development of new prevention and treatment methods of citrus fruit.The study is to explore whether the Penicillium digitatum can reduce the pH of the fruit by in vivo experiments first.Then by quantitative real-time PCR to find out which gene affects Penicillium digitatum regulate the pH of the surrounding environment.After the recognition of the target gene,constructing the recombinant plasmid and knocking out the target gene according to the homologous recombination principle,followed by obtaining the Penicillium digitatum mutants.At last,the mutants are identified by molecular identification and phenotypic identification.The main results of this study are as follows:1.The results showed that the pathogenic bacteria of Penicillium digitatum could decline the pH value of the medium and cirtus fruit.2.The in vivo experiments showed that the pathogenicity of Penicillium digitatum in different pH values was different.In particular,in the alkaline environment,the pathogenicity of Penicillium digitatum was significantly weaker than that in the neutral and acidic environment.3.Through quantitative real-time PCR,we discovered the palF gene may be the gene which can affect the Penicillium digitatum regulate the pH of the surrounding environment.4.Analysis of the conserved domain based on the amino acid sequence of palF gene of Penicillium digitatum,which was found that the pal F protein of Penicillium digitatum contain conservative domain of Arrestin-C and Arrestin-N.It is speculated that palF gene is involved in the signal transduction of environmental pH induced signal transduction pathway.The study of the effect of environmental pH on the pathogenicity of Penicillium digitatum provides a reference for the molecular biology and genetic engineering research,not only Penicillium digitatum,but also other species of Penicillium.