Regulation Of Plant Interspecific Competition On Soil Fungal Community And Its Feedback

Plant-soil feedbacks(PSFs)plays an important role in the process of insect-plant interaction,plant and insect community construction,and has become a hot issue in ecological research.Although plants do not exist alone in nature,a majority of studies focus on the effects of individual plants on soil microbial communities.In this study,plant interspecific competition and plant-soil feedbacks are linked together to explore how plant interspecific competition affects plant rhizosphere microbial community,and what impact it has on contemporary plants and subsequent plants.At the same time,alien invasive plant is combined to explore the differences of focal plants' rhizosphere fungal communities between alien invasive plants and native plants when competing with focal plants.Following results are what we found in this study:1)The composition of the overall and pathogenic fungi varied among plant species and competition treatments: soil that received different competition treatments shared some OTUs,and also has some unique OTUs,respectively.In particular,focal plant rhizospheres had higher abundances of some pathogenic OTUs and lower abundances of other pathogenic OTUs in the presence of native competitors vs.invasive competitors.Phylogenetically related focal species were associated with a higher number of similar pathogens in monocultures,but this pattern was absent in the presence of competitors.2)The soil biota and competitors both decreased the focal plant shoot mass,while the native competitor decreased the focal plant shoot biomass more compared to the invasive competitor;the soil biota decreased the native competitor shoot mass but had no impact on the invasive competitor shoot mass.3)Apparent competition via soil biota was negatively related to focal plants' intrinsic competitive ability and pathogenic fungi richness,which indicates that apparent competition may beneficial to plant coexistence.On the other hand,invasive competitor has weaker competitive ability than the native competitor,but it suffers from weaker apparent competition,indicating that soil biota may promote the invasion of Solidago canadensis through apparent competition.4)Plant interspecific competition had no impact on subsequent phase 3 plants,but the direction and the strength of conspecific or interspecific plant-soil feedback that subsequent experienced varied by plant species: Physalis angulata,Parthenium hysterophorus and Amaranthus lividus were experienced positive conspecific plant-soil feedback,while Conyza sumatrensis,Solanum nigrum,Amaranthus hybridus,Ageratum conyzoides,Aster subulatus,Celosia argentea and Sonchus oleraceus experienced negative conspecific plantsoil feedback.Pterocypsela indica experienced negative interspecific plant-soil legacy feedback,and the strength of the feedback varied with plant species,while Bidens pilosa L experienced positive plant-soil feedback,but plant species had no impact on it.In summary,our results indicated that apparent competition via soil biota plays an important role in plant coexistence and alien plant invasion.However,how the apparent competition will affect the individual performance growth and community construction of insects,and how apparent competition and herbivory jointly regulate plant invasion need to be further explored.