Study On The Changes Of Tea Microbial Community Caused By Leaf Spot Diseas

Guizhou province,as the suitable and main production area of tea trees in China,ranks first in terms of planting area and output value in the country.In recent years,due to climate change in Guizhou Province,the rainy season has also increased year by year,and external factors such as climate and temperature in tea planting areas will change,resulting in changes in the microbial community structure of tea plants,leading to tea plant diseases.In this study,the leaves,root and soil of tea plants from major tea regions in Guizhou Province were used as research objects.Analysis of microbial community structure in both healthy and diseased tea leaves,along with screening of key differential species,was conducted using two distinct techniques: traditional culture and high-throughput sequencing..Analyze the dynamic changes of microbial diversity community in tea leaves during different periods,the dynamic changes of microbial community in tea leaves between different regions,and the differences in microbial community structure between tea roots at different periods.Analyze the relationship between microbial population changes in leaf diseases and microbial community structure changes in tea roots,thereby exploring the impact of microbial communities on tea leaf diseases,understanding the incidence of tea leaf spot disease,and providing a certain scientific basis for the prevention and control of tea leaf diseases.The analysis results are asfollows:(1)For tea leaves from different regions and periods,when diseases occur in the leaves,the microbial diversity and community structure within the leaves will change.The microbial diversity in diseased leaves in Kaiyang tea area is higher than that in healthy leaves,while the microbial diversity in diseased leaves in Shiqian tea area and Sinan tea area is higher than that in healthy leaves.Through PCo A principal coordinate analysis and NMDS non metric multidimensional calibration analysis of microbial community structure in diseased and healthy leaves from different regions and periods,it was found that there were differences in microbial community structure between diseased and healthy leaves.(2)There are differences in microbial diversity and community structure in tea leaves among different tea regions.In August,the diversity and richness of fungal species in the diseased leaves of tea plants in Shiqian tea region were the highest among the three tea regions.In November,the fungal species diversity in diseased tea leaves(first,second,and third leaf positions)in Sinan tea region was the lowest among the three tea regions,while the fungal species diversity in healthy tea leaves in Shiqian tea region was the lowest among the three tea regions.At the same time,the study found that in August,there was no significant difference in the microbial community structure in the tea leaves of the three tea regions,but by November,there were significant differences in the microbial community structure in the tea leaves of the three tea regions.(3)There are differences in microbial diversity and community structure in tea leaves at different stages.For the Kaiyang tea region,the microbial diversity in the leaves in May was the lowest,while the microbial diversity in the leaves(including diseased and healthy leaves)in November was the highest.For the Shiqian tea region,the fungal species diversity in leaves(including diseased and healthy leaves)was the highest in November,while the bacterial species diversity in leaves was the highest in August.For Sinan Tea District,the fungal species diversity in tea plant diseased leaves in August is higher than that in tea plant diseased leaves in November,and the fungal species diversity in tea plant healthy leaves in November is higher than that in tea plant diseased leaves in August.There were no significant differences in the fungal community structure in the healthy leaves of tea plants in different periods of Kaiyang tea region,but there were differences in the bacterial community structure in the leaves of tea plants.(4)At the phylum level,Ascomycota and Basidiomycota are the main phylum lev el species in tea leaves,while Ascomycota,Basidiomycota,and Glomeromycota are th e main phylum level species colonized in tea roots.For Sinan tea region in August,aft er the occurrence of tea leaf disease,the abundance of Ascomycota species increased f rom 92.21% to 99.26%,while the abundance of Basidiomycota species decreased from7.62% to 0.56%.Compared to August in November,the number of Glomeromycota s pecies in the root system of tea plants in the three tea regions increased significantly,w ith the abundance increasing from 0.84% to 28.95%,which may be related to climate change(lower temperature).At the level of fungi,species such as Daviiella,Didymell a,Setophoma,and Mycosphaerella have been colonized in tea leaves for a long time.When tea leaves become diseased,the abundance of Didymella species will increase,while the abundance of Daviiella species will decrease.When Didymella species reach es a certain abundance in tea leaves,it may antagonize Daviiella species,which may l ead to disease in tea leaves.At the bacterial level,Proteobacteria,Cyanobacterium,Ba cteroidota,and Firmicutes are the main bacterial species in the leaves and roots of tea plants,while Actinobacteriota,Chloroflexi,and Myxococcota are a small number of sp ecies that are colonized in the roots of tea plants.The relative abundance of Cyanobac terium species is relatively high in healthy leaves of Sinan tea area in August and Nov ember,while it is relatively low in leaves of Shiqian area and Kaiyang area in August and November.At the bacterial genus level,species such as Methylobacterium Methyl orubrum,Sphingomonas,and Aureimonas are mainly colonized in the leaves of tea tre es,while species such as Burkholderia、Caballeronia、Paraburkholderia,Allohizobi um、Neohizobium、Rhizobium、Bradyrhizobium、and Ralstonia are mainly coloniz ed in the roots of tea trees.(5)We conducted OPLD-DA analysis and independent sample T-test on OTUs of diseased and healthy leaf samples,and based on VIP>1,P<0.05,selected 28 key fungal species(genus level)that differed between diseased and healthy leaves.Screening out15 key differential bacterial species(genus level)between diseased and healthy leaves.At the same time,in order to further characterize the impact of complex interactions between fungal groups on the microbial community of tea leaves,we evaluated the symbiotic network patterns of fungal communities between diseased and healthy leaves.Studies have found that when a leaf disease occurs,more interactions occur between the fungal groups within it.