一株砂生槐根际促生菌的鉴定及其生物学特性研究OA

Many microorganisms were colonized in the rhizosphere soil of Sophora moorcroftiana.Screening and investigating the strains with excellent plant growth-promoting traits can provide a theoretical basis for the development and utilization of promoting bacterial resources of special habitat.In this study,a plant growth-promoting bacterial strain zw27 was isolated from the rhizosphere soil of S.moorcroftiana in Xizang region.The strain zw27 was isolated using the soil ten-fold dilution method.The strain zw27 was identified based on morphological observation,physiolgical and biochemical characterization,and 16S rRNA gene sequence analysis.The production of indole-3-acetic acid for strain zw27 was detected by Salkowski colorimetric method.The phosphate-solubilizing capacity of strain zw27 was assessed using molybdenum-antimony anti-colorimetric method.The single-factor experiment was used to study the types of nutrients and biological characteristics of the strain zw27.The results showed that the strain zw27 is Bacillus proteolyticus.The production of indole-3-acetic acid is(43.468±2.818)μg·mL-1.And phosphate-solubilizing activity is quantified as(65.580±3.509 μg)·mL-1.The strain zw27 achieved maximal growth when it is cultured separately with starch as the carbon source,yeast extract as the nitrogen source,and sodium chloride as the inorganic salt.The strain zw27 exhibits good tolerance under stress conditions including NaCl concentration below 7%,pH ranging from 4 to 10,polyethylene glycol concentration below 15%,and temperatures between 10℃and 20℃.This study can provide microbial strain resource for the development and utilization of plant growth-promoting bacteria in rhizosphere soil of S.moorcroftiana under conditions such as high salinity,drought,and low temperature.