Diversity of culturable endophytic bacteria from Viscum liquidambaricolum and its survival promotion

【Objective】The diversity of cultured endophytic bacteria and their IAA and siderophore production as well as their phosphate and potassium solubilizing abilities were revealed in Viscum liquidambaricolum，and the life-promoting strains were screened，which would provide some basic data and theoretical basis for the subsequent development and utilization of plant endophytic bacteria.【Method】The endophytic bacteria were isolated from the parasitic plant V. liquidambaricolum by four isolation methods and five different media. The endophytic bacteria were identified by 16S rRNA gene sequence，and the phylogenetic tree was constructed to determine the taxonomic status of endophytic bacteria. Strains with ACC deaminase activity were screened from endophytic bacteria，which was isolated from V. liquidambaricolum， and the IAA-producing，siderophore-producing，phosphorus-dissolving and potassium-dissolving abilities of endophytic strains containing ACC deaminase were determined.【Result】60 strains of endophytic bacteria were isolated and purified from V. liquidambaricolum. Through 16S rRNA sequencing and comparative analysis，52 strains of endophytic bacteria from V. liquidambaricolum were obtained after deduplication，which belonged to 22 genera and 15 families. Among them，suspension method（Z method）and cellulose-proline medium（No.4）had the best separation effect，with 16 and 17 genera were obtained respectively，and Curtobacterium was the dominant genus，accounting for 23.08%. The test results of growth-promoting ability showed that among 12 endophytic bacteria with ACC deaminase activity，7 bacteria （58.33%）had IAA-producing ability，among which SWFU34 had the strongest IAA-producing ability，which was 4.95 mg/mL. 10 strains（83.33%）had the ability to produce siderophore；8 strains（66.67%）had the ability of dissolving phosphorus and potassium，among which 4 strains（33.33%）had the ability of producing IAA and siderophore and dissolving phosphorus and potassium at the same time.【Conclusion】V. liquidambaricolum is rich in microbial resources and life-promoting strains，among which Curtobacterium is the dominant genus，Pseudomonas strain SWFU34 is the most prominent one in promoting activity，which has the potential of agricultural application.