The Response Of Rhizosphere Fungal Community In Arabidopsis Thaliana To Bemisia Tabaci Herbivory And Its Dynamic Change

Rhizosphere microbiome,which refers to the fungal and bacterial communities in plants’ rhizosphere soils,has the potential to enhance the responses of plants to abiotic and biotic(e.g.insect herbivore stress)environmental stresses.Therefore,elucidating whether microbes in plants’ rhizosphere can achieve directional changes and improve their resistances to insects under the pressure of insect herbivory has become an urgent issue in the field of plant protection.In addition,the interactions of plants and rhizosphere microbes are affcected by their own growth and development,as well as the existing soil microbial community.However,there is currently a lack of exploration on how plant rhizosphere microbiome responds to insect herbivory and its dynamic change when grown in different soils.Based on this,this study selects Arabidopsis thaliana as research object,applies herbivory stress by Bemisia tabaci,conducts multi-generation domestication experiments,and combines the analysis of plant rhizosphere fungal community.This study explores the dynamic change in plant rhizosphere fungal communities to insect herbivory and their feedbacks on the fitness of plants and insect herbivores when grown in soils from three different origins.The main results of this research are:1)In comparison to plants grown in sterile soils(in the absence of soil microbes),soil microbes had suppressive effects on flowering,harvesting,relative growth rate,stem height,aboveground biomass and seed production of A.thaliana plants(delayed flowering and harvesting,decreased relative growth rate,stem height,aboveground biomass and seed production).The herbivory of B.tabaci had promotitive effects on relative growth rate,stem height,aboveground biomass and seed production of plants grown in sterils soils,while the presence of soil microbes made flowering,relative growth rate,stem height,aboveground biomass and seed production of plants suppressed by B.tabaci herbivory.In addition,soil microbes indirectly decreased the survival of adults and the number of eggs per female of B.tabaci.Flowering time,harvesting time,aboveground biomass and seed production of plants decreased and then increased with the increase of experimental generation,and their changes varied among the original soil microbial community.Survival of adults of B.tabaci feeding on plants grown in sterile and Hubei soils decreased with the increase of experimental generation,but there was no relationship between the number of eggs per female and experimental generation when grown in soil from each origin.2)The herbivory of B.tabaci decreased the relative abundance of Ascomycota,Olpidiomycota,Trichoderma and Olpidium fungi in A.thaliana’s rhizosphere,while increased the relative abundance of Basidiomycota,Mortierellomycota,Darksidea,Mortierlla fungi.In addition,the herbivory of B.tabaci had suppressive effects on the richness of total and pathogenic fungi,but had promotitve effects on the richness of saprophytic fungi,the richness and diversity of mutualistic fungi.Moreover,B.tabaci herbivory changed the overall composition of total,pathogenic and saprophytic fungi.In the absence of B.tabaci,the richness and diversity of total,mutualistic,pathogenic and saprophytic fungi in A.thaliana’s rhizosphere decreased with the increase of experimental generation,while in the presence of B.tabaci,the richness and diversity of mutualistic fungi decreased and then increased with the increase of experimental generation.3)The richness and composition of total,mutualistic,pathogenic and saprophytic fungi,as well as relative abundance of different fungal genera predicted aboveground biomass and seed production of A.thaliana,and their linkages varied due to B.tabaci herbivory.For example,in the absence of B.tabaci,aboveground biomass of plants was positively correlated with the richness of total,pathogenic and saprophytic fungi,as well as relative abundance of fungal genus Trichoderma,while in the presence of B.tabaci,it was negatively correlated with relative abundance of fungal genus Motierlla.In the absence or presence of B.tabaci,aboveground biomass of plants was positively or negatively correlated with the richness of mutualistic fungi respectively,and this pattern was also found in the relationships between aboveground biomass and relative abundance of fungal genus Aspergillus.In the absence of B.tabaci,seed production of plants was negatively correlated with the richness of pathogenic fungi,while in the presence of B.tabaci,seed production was negatively correlated with the richness of total and saprophytic fungi,and was also positively correlated with the composition dissimilarity of saprophytic fungi and fungal genus Motierlla.In addition,the survival of adults of B.tabaci was negatively correlated with the relative abundance of fungal genus Aspergillus,and the number of eggs per female was negatively correlated with the richness of total,pathogenic and saprophytic fungi.The above results indicate that: the herbivory of B.tabaci changed the structure of fungi communities(especially the richness and composition of different functional group fungi)in A.thaliana’s rhizosphere,and the responses of rhizosphere fungal to herbivory and their feedbacks on the fitness of A.thaliana and B.tabaci changed with the increase of experimental generation;the richness and composition of fungi could predict the growth and reproduction of plants,as well as the survival and fecundity of insect herbivores.