生姜根际解磷芽孢杆菌的筛选及其促生效应评价OA北大核心CSTPCD

[Objective]This study aimed to screen and identify phosphate-solubilizing Bacillus strains isolated from the ginger rhizosphere,and evaluate their phosphorus solubilization ability and growth-promoting effect,thereby provi-ding a theoretical basis for the exploration of phosphate-solubilizing Bacillus resources in ginger rhizosphere and the de-velopment and utilization of microbial fertilizers.[Method]Using 296 Bacillus strains in ginger rhizosphere as the test strains,strains capable of efficiently hydrolyzing calcium phosphate were screened through an inorganic phosphorus-selective media.Through indoor experiments,the phosphorus solubilization activity and auxin(IAA)production capacity of phosphate-solubilizing strains were analyzed.A greenhouse pot experiment was conducted to evaluate the growth-promoting effects of phosphate-solubilizing strains on maize and ginger and their impacts on the available phosphorus con-tent in rhizosphere soil.The classification status of phosphorous solubilizing strains was determined based on morphologi-cal observation,physiological and biochemical characteristics tests,and 16S rRNA sequence analysis.[Result]Six strains with notable phosphorus solubilization activity were screened from the 296 Bacillus strains in ginger rhizosphere,namely strains L9,L11,L12,L54,HC-5 and C42.Indoor experimental results revealed that after 5 d of inoculation,the soluble phosphorus content in the fermentation broth of the 6 strains reached their peak,with a concentrations range of 118.90 to 179.33 mg/L.After 48 h of shaking culture,the IAA content in the fermentation broth of the 6 strains ranged from 2.09 to 3.49 μmol/L.By analyzing the relationship between the soluble phosphorus content and pH value in the NBRIP culture li-quid,it was discovered that there was a significant negative correlation between the soluble phosphorus content and the pH value within 1-5 d after inoculation(P＜0.05,the same below).Seed germination test results showed that strains C42 and L54 significantly increased the germination rate and germination potential of maize seeds.Under greenhouse pot condi-tions,strains L54 and LI 1 showed better performance in promoting maize plant growth and phosphorus solubilization abi-lity.Compared with the blank control,the plant height,leaf length,root length,shoot fresh weight,root fresh weight and shoot dry weight of maize treated with strains L54 and L11 increased by 11.11％-88.89％,and the available phosphorus content in rhizospheric soil increased by 49.29％and 42.46％respectively.Similarly,after treatment with strains L54 and L11,the plant height,shoot fresh weight and ginger tuber fresh weight also increased significantly by 17.94％-42.06％,and the available phosphorus content in the rhizospheric soil increased by 73.80％and 69.45％respectively.After identifi-cation,all 6 phosphate-solubilizing strains were B.velezensis.[Conclusion]The 6 B.velezensis strains screened from the ginger rhizosphere show excellent phosphate-solubilizing ability,these strains can effectively promote the growth of maize and ginger plants,and increase available phosphorus content of maize and ginger rhizospheric soil,thus possess the potential to be developed as microbial fertilizers.