马拉硫磷降解菌缺陷短波单胞菌L19菌株的luxAB基因标记及其在土壤中的存活

luxAB labelling of malathion-degrading strain L19 of Brevundimonas diminuta and its fate in soils

采用电转化法成功的将带有发光酶基因luxAB的质粒pTR102导入缺陷短波单胞菌L19菌株(Brevundimonas diminuta L19)中,考察了电击时间、电击场强、细胞生长时期等因素对转化效率的影响。测定了转化子L19-luxAB菌株的遗传稳定性以及标记基因的介入对L19菌株降解有机磷农药能力的影响,研究了L19菌株在土壤中的定殖动态和降解马拉硫磷的能力。结果表明,转化子L19-luxAB具有发光活性和对卡那霉素的抗性,遗传稳定性强,在抗性平板上传代15次仍有很强的发光活性,并且标记菌株与出发菌株对有机磷农药的降解能力无显著差异。证明可以应用L19-luxAB进行菌株土壤定殖生态学研究。标记菌株在灭菌土壤和自然土壤中均能很好的存活,具有明显的降解马拉硫磷的能力。

The plasmid pTR102 with luxAB gene was successfully introduced in Brevundimonas diminuta L19 strain by electroporation to monitor colonization dynamics of the strain in the natural environment. The influencing factors, such as pulse field strength, pulse time and optical density at λ600nm of the culture on transformation efficiency were tested. The luxAB gene was expressed in the transformant strain L19-1uxAB, and after continual transfer for 15 generations, the characteristic of luminescence was still stable. The survival conditions for L19-luxAB in soil were studied. The results showed that L19-luxAB stably colonized in the soil after 40 d and the L19-luxAB strain_had high ability in degradation of malathion in soil.