Differences Of PH Values,Nutrients, And Microbial Diversities Between Healthy And Diseased Carya Cathayensis

In order to investigate the effect of microbial diversity and function of Carya cathayensis on canker disease,this article adopted high-throughput sequencing,compared the differences of pH values,nutrients,bacteria and fungi diversity in sick parts and healthy parts of bark and xylem of healthy and diseased hickory trees,and their correlations were analyzed.The main findings are as follows:1.The pH values of bark and xylem of healthy hickory trees were 7.03 and 7.63,respectively,which were significantly higher than those of acidic diseased hickory trees(P<0.05).2.The contents of tannin and soluble sugar in healthy bark were 0.317% and 3.348%respectively,and two kinds of nutrient contents in xylem were 0.079% and 0.626%,respectively,which were significantly higher than those diseased hickory trees(P<0.05).The contents of reducing sugar in the bark and xylem of healthy hickory trees were 0.865%and 0.420%,respectively,which were significantly lower than those diseased hickory trees(P<0.05).3.The amount of bacterial and fungal OTU in bark of healthy hickory trees was significantly higher than that in infected hickory trees,the amount of bacterial OTU in xylem was significantly lower than that in diseased hickory trees and the amount of fungal OTU is significantly higher than that in diseased ones.The main bacterial genera of the healthy hickory trees,the diseased part of hickory trees and the non-diseased part of the hickory trees,the amount of bark are respectively 7,8,8,xylem,respectively 8,4,8,the bark of the major fungi are 7,12,5,xylem,respectively 8,3,6.There were significant differences in species and abundance between healthy and diseased hickory bark and xylem(P<0.05).The dominant bacterial genera of healthy hickory bark were Bdellovibrio,Acidocella,Sphingomonas,with abundance of 0.13%,0.01% and 15.32% respectively,for the dominant fungus Epicoccum,0.111%,the dominant bacterial genera of xylem are Massilia,Sphingomonas,with abundance respectively 1.2%,4.41%,for the dominant fungus Rhinocladiella,4.47%,all of there indicators were significantly higher than diseased hickory trees(P<0.05).The hickory diseased and non-diseased bark,the dominant bacterial genera were Byssovorax and Methylobacterium,abundance of the 2 bacterial genera was 7.56% and 6.46% respectively.The dominant fungi genera were Devriesia and Spizellomyces,abundance of 2 bacterial genera was 10.44% and 0.014% respectively,significantly higher than that of non-diseased parts,and abundance of hickory trees in twoparts of the bark of 4 bacterial genera were significantly higher than that of healthy hickory trees(P<0.05).The hickory diseased and non-diseased xylem,the dominant bacterial genera were Methylobacterium,Luedemannella and Byssovorax,abundance of the 4bacterial genera was 2.36%,0.35%,2.35% and 1.76%,1.81%,0.55% respectively,Phoma and Candida was the dominant genus of fungi,abundance was 1.31%,1.85% and 0.51%,0.84% respectively,and the diseased hickory trees in two parts of the xylem of 5 bacterial abundance were significantly higher than that of healthy hickory trees(P<0.05).4.The bacterial diversity index of Ace,Chao,Shannon and Simpson in bark and xylem of healthy hickory trees are 599,603,6.59,0.98,and 440,454,6.35,0.95 respectively.The diversity index of these four fungi were 321,318,4.42,0.92 and 311,263,5.93,0.96(P<0.05).5.RDA analysis showed that pH values,soluble sugar and reducing sugar had significant effects on the dominant genera of bacteria and fungi in bark and xylem of hickory trees(P<0.05)The results can be used for reference for sustainable and healthy management of hickory forest.