Isolation and identification of saline-alkali tolerance bacteria DQSA1 and its growth-promoting effect on mung bean under saline-alkali stress

Abstract:

[Background] In recent years, the degree of soil salinization in Daqing has been gradually intensified. microbial improvement of saline-alkali soil is a hot research topic now. [Objective] Saline-alkali tolerance bacteria were screened out from Daqing saline-alkali soil, verify its growth-promoting effect, providing microbial resources for improving the saline-alkali soil in Daqing. [Methods] Screening mediums were used to separate saline-alkali tolerance and growth-promoting bacteria from Daqing saline-alkali, the strains were identified by morphological observation, physiological and biochemical identification and 16S rRNA gene sequence analysis, the effect of strains on mung bean growth and soil bacterial community structure under saline-alkali stress was tested. [Results] A saline-alkali tolerance and growth-promoting strain DQSA1 was screened, which could fix nitrogen and produce ACC deaminase, siderophore and indole-3-acetic acid (IAA), and identified through physiological and biochemical identification and phylogenetic analysis as Zobellella. Inoculation of strain DQSA1 after planting mung beans in saline soil, the fresh root weight, root dry weight and chlorophyll content of mung bean after treatment increased significantly, increased by 33%, 32% and 79% respectively. strain DQSA1 could significantly increase the content of soluble sugar, proline and soluble protein in mung bean leaves, increase by 10%, 80% and 73%, respectively. Compared with the content of CK, the proline content and soluble protein content of mung bean roots were increased by 78% and 44%, respectively. High-throughput sequencing was performed on the soil in which mung bean were grown, the results showed that the strain DQSA1 can colonization in a saline-alkali environment and promote the growth of beneficial Rhizobium spp. and Sphingosine spp. [Conclusion] strain DQSA1 could change the soil bacterial and promote plant growth under saline-alkali conditions, providing effective microbial resources for improving saline-alkali soil.