The Effects Experimental Of Warming And Nitrogen Deposition On Bacterial Community Under Different Root Microhabitats Of Solidago Canadensis

With the acceleration of economic and social globalization process,the intension and frequency of human activity is increasingly growing,which amplified the effects of global alien biological invasion and global changes dramatically.Alien biological invasion and global changes(e.g.,global climate warming and nitrogen deposition)have been important parts of global environmental problems and ecological focus.Although many studies have reported that global climate warming and nitrogen deposition can directly or indirectly affect the invasion process of alien plants,the effects of the two factors on different micro-habitat microorganisms in the root of invasive plants are extremely scarce.Therefore,the notorious Solidago canadensis and micro-habitat microorganisms of the roots was chose as research object,using high throughput sequencing technology and metagenomic analysis to explore global climate warming and nitrogen deposition on the bacterial community structure of rhizosphere,rhizoplane and endosphere of S.canadensis.We hope to reveal the responses of bacteria of different microhabitat in root of exotic invasive plant to global climate warming and nitrogen deposition,providing new insight of microbial mechanism of the successful invasion of exotic plant.The research results are as follows:(1)Warming and nitrogen addition changed the abundance and diversity of root bacteria of S.canadensis:(1)Under natural condition,the species abundance of bacteria of root bacteria was successively decreased following such an order: rhizosphere > endosphere > rhizoplane.When the living environment changed,the species abundance of bacteria of root bacteria was successively decreased following such an order: rhizosphere > rhizoplane > endosphere.(2)During S.canadensis invasion process,the Shannon diversity index of plant root bacteria showed a decreasing trend from rhizosphere,rhizoplane and endosphere.Moreover,the Shannon diversity index of the rhizospheric and rhizoplane bacteria of S.canadensis is not sensitive to the response of environmental change,and it responded sensitively to environmental change in endophytic bacteria.(2)Warming and nitrogen addition significant changed the community composition of root bacteria of S.canadensis:(1)Plant rhizospheric bacteria was mainly composed of Proteobacteria,Actinobacteria and Acidobacteri,rhizoplane bacteria was mainly composed of Proteobacteria,Actinobacteria and Firmicutes,endophytic bacteria was mainly composed of Cyanobacteria,Proteobacteria and Firmicutes.There were significant differences among the dominant bacteria under different environmental treatments.(2)The abundance and community composition of root bacteria showed distinct difference at the phylum and genus levels.(3)Warming and nitrogen addition turned rhizospheric and rhizoplane bacterial community divergent,while turned endophytic bacterial community convergent.(3)Plant growth promoting bacteria of S.canadensis were sensitive to warming and nitrogen addition:(1)Warming significant promoted the growth of growth promoting bacteria in the rhizospheric microhabitat of S.canadensis,but nitrogen addition inhibited the growth of plant growth promoting bacteria in the rhizospheric microhabitat of S.canadensis.This situation is completely opposite in the rhizoplane microhabitat of S.canadensis.(2)Warming and nitrogen addition significantly inhibited the growth of growth promoting bacteria in the endophtic microhabitat of S.canadensis.(4)The changes of copitotrophic groups and oligotrophic groups of S.canadensis were complex.(1)Plant root copitotrophic groups were more sensitive to environmental changes,while oligotrophic groups showed the opposite trend.(2)Warming or nitrogen addition benefited the growth of copitotrophic groups in rhizoplane,however the combination of warming and nitrogen addition inhibited the growth of copitotrophic groups in rhizoplane.Integrated the above results,we further confirmed that S.canadensis invasion obviously altered the community composition and structure of root bacteria,and turned root bacterial community structure convergent,experimental warming and nitrogen deposition had further magnified or narrowed the difference of root bacterial composition between plants.In addition,the fine division of plant root bacteria(rhizosphere,rhizoplane and endosphere)in this paper deepened the research on the interaction between root bacterial community and invasive plants,and provided a new way of thinking for further expand research in this field.