耐盐碱细菌DQSA1的分离鉴定及盐碱胁迫下对绿豆的促生作用

【背景】近年来,大庆地区土壤盐碱化程度逐渐加剧,而微生物改良盐碱土是当今的研究热点。【目的】从大庆盐碱土中筛选出耐盐碱菌株,验证其促生作用,为改良大庆盐碱土壤提供微生物资源。【方法】采用筛选培养基从大庆盐碱土中获得耐盐碱促生菌,对其进行形态学观察、生理生化和16S rRNA基因鉴定,并测试菌株在盐碱胁迫下对绿豆植株和土壤细菌群落结构的影响。【结果】筛选得到一株耐盐碱促生菌DQSA1,具有固氮、产ACC脱氨酶、产铁载体、产吲哚乙酸(Indole-3-Acetic Acid,IAA)功能;通过生理生化鉴定和系统发育分析,判定该菌株为卓贝尔氏菌属(Zobellella)。在盐碱土中种植绿豆后接种菌株DQSA1,处理后的绿豆较对照相比根系鲜重、根系干重及叶绿素含量分别增加了33%、32%和79%;植株叶部可溶性糖、脯氨酸和可溶性蛋白含量分别升高了10%、80%和73%;根系的脯氨酸及可溶性蛋白含量分别增加了78%和44%。对种植绿豆的土壤细菌进行高通量测序,发现菌株DQSA1可以在盐碱环境下定殖并促进根瘤菌和鞘氨醇杆菌等有益菌的生长。【结论】菌株DQSA1可以在盐碱条件下调节土壤细菌群落结构并促进植物生长,为改良盐碱土地提供了有效的微生物资源。

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

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.