欧李内生促生菌分离、鉴定及促生、耐盐碱特性

Isolation and identification as well as growth enhancement and saline-alkali tolerance properties of Cerasus humilis plant growth-promoting endophytes

为获得欧李(Cerasus humilis)根系优良内生促生菌,以欧李根系为研究材料,采用组织匀浆法分离纯化可培养内生细菌,测定其固氮、解磷、溶磷、合成植物生长素IAA(吲哚乙酸)和耐盐碱特性,并通过16S rRNA序列系统发育分析进行初步鉴定。结果显示:分离的7株菌均表现出一定的促生潜力,菌株固氮酶活性在50.64~127.40 nmol·h^(-1)·mL^(-1),菌株Y3最高;菌株解有机磷量在1.28~358.90μg·mL^(-1),菌株N23最高;菌株溶无机磷量在6.29~143.61μg·mL^(-1),菌株Y2最高;菌株合成IAA量在14.24~70.48μg·mL^(-1),菌株N22最高。菌株耐盐碱特性测定中,菌株Y3、Y4表现出广泛的耐盐碱特性,可在NaCl浓度为30%以及pH值为13的条件下正常生长,属极端嗜盐嗜碱微生物。16S rRNA序列系统发育分析结果,菌株Y3、Y4确定为Bacillus sp.,菌株N23、N22为Pseudomonas simiae,菌株N1为Brevibacterium frigoritolerans,菌株Y1、Y2为Achromobacter marplatensis。研究分离出的内生促生菌具有多种优质促生特性,可为后续研制微生物接种剂(菌肥)提供优良菌种,并有望在绿色农业发展中发挥积极作用。

To obtain Cerasus humilis root plant growth-promoting endophytes,PGPE,we took the root system of Cerasus humilis as the research object and used tissue homogenization method to isolate and purify cultivable endophytic bacteria to determine its nitrogen fixation,phosphorus-dissolving,phosphorus-solubilizing,IAA production and saline-alkali tolerance properties.We also tried to use phylogenetic analysis of 16S rRNA sequence for preliminary identification.The results showed that the 7 isolated strains all showed a certain growth potential.The nitrogen fixation activity of strains was within the range between 50.64~127.40 nmol·mL^(-1),and the Y3 strain had the highest nitrogen fixation activity.The dissolution of organic phosphorus strains was within the range between 1.28~358.90μg·mL^(-1),and the N23 strain had the highest capacity of dissolving organic phosphorus.The solubilization of inorganic phosphorus strains was within the range between 6.29~143.61μg·mL^(-1),and the Y2 strain had the highest capacity of solubilizing inorganic phosphorus.The content of IAA synthesized by the strain was between 14.24μg·mL^(-1)and 70.48μg·mL^(-1),and the content of IAA synthesized by the N22 strain was the highest.In addition,the Y3 and Y4 strains showed a wide range of saline-alkali tolerance characteristics and grew normally under the condition of 30%NaCl concentration and pH of 13.They were extremely halophilic and alkalophilic micro-organisms.As a result of phylogenetic analysis of 16S rRNA sequence,the Y3 and Y4 strains were identified as Bacillus sp.N23 and N22 strains were Pseudomonas simiae.Strain N1 was Brevibacterium frigoritolerans.The Y1 and Y2 strains were Achromobacter marplatensis.The PGPE isolated in this study contained a variety of high-quality growth-promoting properties,which could provide excellent strains for the subsequent development of microbial inoculants(bacterial fertilizers)and play an active role in the development of green agriculture.