Effects Of Tomato Root Exudates On Growth Of Rhizosphere Microorganisms Andnematode Biocontrol Fungi

Plant root exudates may determine plant-specific rhizosphere microflora.Provides a more favorable microbial community basis for plant-soil feedback,providing optimal soil conditions for crop yield and environmental sustainability.This study firstly clarified the relationship between tomato and Aspergillus niger growth,and then led the root exudates to study the effects of secretions on the growth of A.niger and allelopathic effects on other fungi in the soil,finally,the effects of secretions on microbial community structure and diversity in rhizosphere soil were analyzed.The purpose is to explore the use of root exudates to relieve the inhibition of soil environment on biocontrol bacteria such as A.niger and the feasibility of application of A.niger.The main findings are as follows:1.A.niger can adhere to tomato roots,and some hyphae invade into the root tissue,both A.niger and tomato plants can grow together without adverse effects.Root exudates can promote the germination of A.niger spores,the rapid growth of hyphae and the formation of colonies.2.The main components of tomato root exudates are benzothiazole,anthracene,octadecane,nonadecane,propionic acid,2-ethylthio-ethyl ester,eicosane,tetradecane,2-dodecene.1-yl-succinic anhydride,5H dibenzo[a,d]cyclohepten-5-one,cyclohexene,2-piperidone,1-heptadecenene,11,13-dimethyl-12-tetradecen-l-of acetate,hydrazine,4-phenyl-3,4-dihydroisoquinoline,1H-indole-2-carboxylic acid,6-4-ethoxyphenyl-3-methyl-4-oxo-4,5,6,7-tetrahydro-isopropyl ester,dibenzofuran,phthalic acid and the like.3.Root exudates can induce the chemotactic growth of three A.niger and five other soil fungi.A.niger strain H1-1 is more sensitive to root exudates and has the strongest tropism.Among the five fungi,one strain of Fusarium oxysporum evades growth,and the other tends to grow.This indicates that tomato root exudates can selectively attract soil fungi,the tendency of A.niger and the promotion of tomato root exudates on the growth of A.niger are important prerequisites for the release of soil growth inhibition.4.Effects of tomato root exudates on soil microbial diversityIn the presence of root exudates,the relatively high abundance of bacteria in the soil is as follows:The relative abundance of Proteobacteria decreased,the relative abundance of Acidobacteria increased,the relative abundance of Actinobacteria fluctuated up and down,and the relative abundance of Chloroflexi fluctuated up and down,the relative abundance of Gemmatimonadetes is less varnable.Planctomyeetes,Bacteroidetes,Nitrospirae,Verrucomicrobia,Saccharibacteria,Armatimonadetes,Cyanobacteria,Firmicutes,Latescibacteria,Tectomicrobia,Chlorobi,Elusimicrobia and other relative abundances below 0.05%.the trend is not obvious.Similarly,the relatively abundant abundance of fungi in soil samples is as follows:the relative abundance of Ascomycota is reduced by more than 0.1%,and the relative abundance of Zygomycota fluctuates,the relative abundance of Basidiomycota was less changed,the relative abundance of Chytridiomycota increased,and the relative abundance of Cercozoa increased slightly.The relative abundances of Rozellomycota,Ciliophora,Neocallimastigomycota and Glomeromycota are not obvious.