Molecular Mechanisms Of Cytochroome P450s From Leptographium Qinlingensis Overcoming Host Resistance

Leptographium qinlingensis is a major pathogenic fungi that damages the xylem and phloem of Pinus armandi in the natural forest ecosystem of the Qinling and Bashan Mountains forests.The inoculation of the symbiosis fungi with Dendroctonus armandi results in a decrease in the resistance of the host tree,which in turn triggers the occurrence of other diseases and pests,and has a destructive impact on the forest ecological environment.Cytochrome P450 enzyme is one of the important enzyme systems in fungal metabolism,and it plays an important role in the process by which fungi degrade chemical defense substance produced by hosts.The study includes these aspects: analysis L.qinlingensis P450 genes phylogeny;research the L.qinlingensis P450 genes' expression profiles in different nutrients and concentrations of terpenoids for host allelochemicals.The main results are as follows:(1)Thirty-two L.qinlingensis P450 genes were obtained by transcriptome sequencing and annotation.The phylogenetic analysis revealed that twenty L.qinlingensis P450 shared more than 51% homology with P450 genes in Grosmannia and Ophiostoma.(2)The result showed that the expression of five P450 genes could be induced in methanol extract in the Phloem of P.armandi and oleic acid medium;the expression of five L.qinlingensis P450 genes in inorganic nitrogen medium was significantly inhibited,but it had the fastest mycelial growth rate.(3)The expression level of L.qinlingensis P450 genes were significant affected on terpenoids.Five P450 genes can be inhibited by monoterpene mixture,while the(±)-?-pinene and(+)-limonene have induced effect on them;only the concentrations of(+)-limonene had a significant effect on the expression of C12461,there was no significant difference in the expression of the four P450 genes on other terpenoids.The results of this study revealed that L.qinlingensis P450 genes can be induced by different nutrients and terpenoids,in addition,L.qinlingensis P450 genes can regulate the expression level of cytochrome P450 enzyme,and it has played an even more important role in overcoming resistant substances and assisting D.armandi to invade host.