Methylopila sp.SD-1与大豆联合修复苯磺隆污染土壤

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1.0×10⁷CFU/mL增至6.7×10⁷CFU/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%.

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

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 1.0×10⁷CFU/mL to 6.7×10⁷CFU/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%.