IMPACT OF INOCULATION WITH AM FUNGI ON MICROBIAL COMMUNITY STRUCTURE IN SOYBEAN RHIZOSPHERE IN FARMLAND OF BLACK SOIL
To explore impact of inoculation with arbuscular mycorrhizal (AM) fungi on microbial community structure in soybean rhizosphere,a field experiment was carried out using soybean as object of the study.Two different strains of AM fungi,Glomus intraradices (GI) and Glomus mosseae (GM),were inoculated into the experiment field with soybean seeds in Treatments GI and GM,respectively,and not in Treatments F (fertilized only) and CK (neither fertilized nor inoculated) as control for comparison.Traditional and modern molecular biological approaches were employed to investigate microbial community structure in the rhizospherel and AM fungi diversity in the root system of the soybean.Results show that both the two strains of AM fungi could colonize soybean roots,forming mycorrhizal symbionts in the field,with colonization rate reaching 78.3％ and 86.6％ in Treatments GI and GM,respectively,and 15.3％ and 16.0％ in Treatments F and CK,respectively,which indicates that indigenous AM fungi can also form mycorrhizal symbionts in the field,but their colonization rates were much lower.Analysis using the dilution-plate method of community structure of culturable microbes in the soybean rhizosphere revealed that Treatments GI,GM and F all significantly elevated the abundance of the three soil microbiota:bacteria,fungi and actinomyces,as compared with CK (p ＜0.05).The effect was the highest on bacteria and actinomyces in Treatment F and on fungi in Treatment GM.Besides,the wet sieve decantation and sucrose centrifugation method was used to isolate AM fungal spores from the rhizospheric soil samples collected at the pod-setting stage of soybean.As a result,3 species in Acaulospora genus and 7 in Glomus genus were obtained,with G.intraradices and G.mosseae being the dominant species,separately,in the genera and they were all quite low in spere density.Afterwards,PCR-DGGE was carried out,to explore band abundance and sequence dominant bands of the PCR-DGGE profiles in the root system and rhizospheric soil of soybean at the pod-setting stage.Molecular detection shows that the population of AM fungi was remarkably higher in the soybean rhizospheric soil than in the soybean root system,and the abundance of AM fungi was the highest in the soybean root system of Treatment GM,while the population of AM fungi in soil was the lowest in Treatment F.In Treatments GI and GM,the dominant fungus species in both soybean root system and rhizospheric soil were the inoculated exogenous AM fungi,which demonstrates the effectiveness and feasibility of application of AM inoculants.The findings of this study has supplied some basic data for promotion of the application of AM fungi inoculant in the field.
AM fungiMicrobial communityMycorrhizal colonization rateDGGEAbundance
国家科技期刊平台
NSTL
万方数据
维普
