螃蟹脚可培养内生细菌多样性及其促生活性研究

【目的】揭示螃蟹脚可培养内生细菌的多样性及其产IAA、铁载体及解磷、解钾能力，筛选具促生活性菌株，为后续植物内生细菌资源的开发与利用提供一定的基础数据和理论依据。【方法】以寄生植物螃蟹脚为研究材料，采用4种分离方法和5种不同培养基分离其内生细菌，通过16S rRNA基因序列对内生细菌进行鉴定，并构建系统发育进化树确定内生细菌的分类地位；从分离获得的螃蟹脚内生细菌中筛选具有ACC脱氨酶活性菌株，并对含ACC脱氨酶内生菌株的产IAA、铁载体及解磷、解钾能力进行测定。【结果】从螃蟹脚中共分离纯化获得60株内生细菌，通过16SrRNA测序及比对分析，去重复后共获得52株螃蟹脚内生细菌，分属于15科22属，其中以悬浮法（Z法）和纤维素—脯氨酸培养基（4号）的分离效果最佳，分别获得16和17个菌属，且以短小杆菌属（Curtobacterium）为优势菌属，占23.08%。促生能力测定结果表明，12株具ACC脱氨酶活性的内生细菌中7株菌（占58.33%）具有产IAA能力，其中菌株SWFU34产IAA能力最强，为4.95mg/mL；10株菌（占83.33%）具有产铁载体能力；8株菌（占66.67%）具解磷和解钾能力，其中有4株菌株（占33.33%）同时具有产IAA、铁载体及解磷、解钾能力。【结论】螃蟹脚蕴藏着丰富的微生物资源及具促生活性的菌株，其中短小杆菌属为优势菌属，假单胞菌属菌株SWFU34的促生活性最突出，具有农业应用的潜力。

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.