Methylopila sp.SD-1与大豆联合修复苯磺隆污染土壤

Combined remediation of tribenuron methyl-contaminated soil by Methylopila sp.SD-1 and soybean.

分离得到1株苯磺隆降解菌株SD-1,根据表型、生理生化特征及16S rRNA基因序列分析,将其鉴定为Methylopila sp.SD-1,为首次报道能够降解苯磺隆的Methylopila属菌株,其在4d内完全降解50mg/L苯磺隆,最适降解温度、pH值分别为30℃和7.0,降解中间产物对大豆的毒性显著降低.大豆根系分泌物能促进菌株SD-1的生长,培养5d,菌株SD-1的数量由1.0×10^7CFU/mL增至6.7×10^7CFU/mL.分泌物中含有16种氨基酸,菌株SD-1对其中的Asp、Glu和Phe表现出明显的趋化性.接种菌悬液至苯磺隆污染土壤(3mg/kg)并种植大豆幼苗,培养4d,菌株SD-1依赖趋化性向大豆根系运动并定殖,存活率提高,根际土壤中苯磺隆的降解率相较于未种植大豆的处理提高36.0%.

One highly efficient tribenuron methyl-degrading strain,named SD-1,was isolated.According to the phenotypic,physiological and biochemical characteristics,combined with 16S rRNA gene sequence analysis,the strain SD-1 was identified as Methylopila sp.SD-1,which was the first reported strain in the genus of Methylopila that could degrade tribenuron methyl.The strain SD-1 completely degraded 50mg/L of tribenuron methyl in 4d.The optimum temperature and pH were 30℃and 7.0,respectively.The toxicity of the intermediate from the degradation of tribenuron methyl to soybean growth was significantly reduced.Soybean root exudates proved to promote the growth of strain SD-1,the number of strain SD-1increased from 1.0×10^7CFU/mL to 6.7×10^7CFU/mL after 5d.Root exudates contained 16 kinds of amino acids,and the strain SD-1 showed chemotaxis response towards Asp,Glu and Phe in root exudates.The suspension of strain SD-1 was inoculated and the soybean was planted in the soil polluted by tribenuron methyl(3mg/kg).After 4days,strain SD-1 colonized on the root of soybean depending on chemotaxis,and the survival rate of SD-1 was increased.Compared with the treatments that didn’t plant soybean,the degradation rates of tribenuron methyl by strain SD-1 in the soybean rhizosphere soil were increased by 36.0%.