The Structure And Functional Alteration Of The Rhizosphere Bacterial Community Of Solidago Canadensis L. Under Different Invasion Intensities

While most studies of invasive plants have focused on macro-organisms,it has becoming increasingly clear that microorganisms are pervasive and play central roles in the success processes of plant invasion.However,few researches have combined microbial communities and their functions to the study of invasive plants.In this study,we take Solidago canadensis L.as the focal invasive plant,using the high-throughput DNA sequencing technology to analyzing the bacterial communities colonized in the root zone,moreover,we use culture-dependent method to detect the capacity of the indole-3-acetic acid secretion by the responsive bacteria to future understand the interactive relationship between rhizosphere bacteria community function and plant invasion.Finally,we obtained the following three conclusions:1.Through the analysis of the high-throughput DNA sequencing data obtained from different samples,we find out that there is a huge difference between the composition and structure of the bacterial community from inside the plant root and the root-soil interface.Specifically,at the phylum level,most of the bacteria inside the roots are belonging to the phylum of Proteobacteria(>99.9%),however,the bacteria colonized at the root-soil interface have an enriched bacterial diversity,largely composed of Proteobacteria,Firmicutes,Actinobacteria,Bacteroidetes and Chloroflexi.This indicates that the recruitment process of the roots of S.canadensis have a strong selective effect towards the rhizosphere bacteria.2.Regardless of the culture-dependent and culture-independent methods,the Alpha and Beta diversity of the rhizoplane bacteria is different according to the invasion intensities of the invasive plant,mainly in the relative abundance of Pseudomonas,Enterobacter,Arthrobacter,Janthinobacterium,Pantoea and Flavobacterium.This indicates that the invasive intensities of invasive plant S.canadensis can affect the structure and composition of the rhizoplane bacterial community.3.Using culture-dependent method to detect the indole-3-acetic acid secretion capacity by the bacteria isolated from different invasion intensities according to the Alpha diversity obtained from culture-independent method and the future inoculation experiment show that the bacteria community effectively promotes the growth of plants.The results obtained suggested that the invasive plant S.canadensis can manipulate the rhizosphere function by regulate the composition and structure of the bacterial communities,and finally this may influence the invasion process.This paper aims to study the bacterial communities(Alpha and Beta diversity)and community function(indole-3-acetic acid secretion capacity)under different invasion intensities by analyzing the rhizosphere bacteria community.This study deepens our understanding of the interaction between invasive plant and rhizosphere bacterial communities,provide a new way of thinking for further expand research in this field.