离子型稀土矿植物根际促生芽孢杆菌的筛选与鉴定

Isolation and identification of plant growth promoting rhizobacteria Bacillus in the ionic rare-earth mines

以离子型稀土废弃矿修复植物的根际土壤为研究对象,采用稀释涂布法从土壤样品中筛选出具有植物根际促生作用,以及能够在高浓度稀土离子条件下生长的芽孢杆菌菌株,并对菌株的促生能力和稀土离子耐受性进行测试。试验结果表明,筛选得到的芽孢杆菌菌株中具有产吲哚乙酸(IAA)能力的有14株,其中同时具有产铁载体和NH3能力的共有5株。菌株Y18-3不仅具有较好的促生特性,而且对稀土离子铥和铽表现出较强的耐受性,半抑制浓度(IC50)分别为2.22和2.29 mmol/L,经16S rRNA基因序列分析法鉴定菌属为纺锤形赖氨酸芽孢杆菌(Lysinibacillus)。

In order to obtain some Bacillus strains that can promote plant rhizosphere growth and reproduce normally under high concentrations of rare earth ions,bacteria were isolated from rhizospheric soil of phytoremediation plants in the ionic rare earth mine tailings by the dilution-plate method.After isolation,their growth promoting ability was investigated,including the production of indole acetic acid(IAA),siderophore and NH3,and the tolerance of rare earth ions.Among the total,14 strains have the ability to produce IAA,and 5 strains can produce IAA,siderophores and NH3.Strain Y18-3 not only shows better growth-promoting performance,but also has stronger tolerance to Tm3+and Tb3+,with half maximal inhibitory concentration(IC50)reaching 2.22 and 2.29 mmol/L,respectively.Based on the 16S rRNA gene sequence identification,strain Y18-3 belongs to the genus Lysinibacillus.