红树林沉积物氟耐受细菌多样性分析及高耐氟菌株筛选

Diversity analysis of fluorine-tolerant bacteria in mangrove sediments and screening of highly fluorine-tolerant strains

关键词:  红树林沉积物，氟耐受，细菌，多样性，crcB

Key words:  Mangrove sediment, fluoride tolerance, bacteria, diversity, crcB

摘要:

为了获得能够耐受高浓度氟离子的微生物，本研究以海南省东寨港红树林保护中心的沉积物为研究对象，分析沉积物中氟耐受细菌的多样性，筛选出高耐氟细菌。系统发育分析表明，沉积物中分离到22种氟耐受细菌，隶属于3门5纲9目12科18属，沉积物中的氟耐受细菌具有丰富的多样性。平板生长法评估表明，14株细菌耐受50 mmol/L NaF，其中有5株耐受200 mmol/L NaF。5株高氟耐受细菌分布于4个属并来源于不同的样品，说明东寨港红树林保护中心不同地域间沉积物中均具有高氟耐受细菌。通过氟胁迫下生长曲线监测筛选到一株在200 mmol/L NaF下仍生长良好的细菌Agrobacterium salinitolerans 3-2-2 3，并被选为进一步的研究对象。特异性引物PCR扩增结果表明，菌株Agrobacterium salinitolerans 3-2-2 3携带了氟耐受基因crcB基因。蛋白电泳表明，菌株Agrobacterium salinitolerans 3-2-2 3在F?诱导下可表达出新的蛋白条带，该蛋白条带可能作为离子载体进行菌体自身解毒。综上，海南省东寨港红树林沉积物蕴含着丰富的氟耐受细菌，菌株Agrobacterium salinitolerans 3-2-2 3具有良好的高耐氟能力，其氟耐受机制以及是否存在含氟代谢产物有待进一步研究。

Abstract:

In order to find microbial organisms that can tolerate high concentrations of F?. The sediment of Mangrove protection center in Dongzhai Port, Hainan Province was taken as the research object. The diversity of fluorine-tolerant bacteria in sediments was analyzed, and high fluorine-tolerant bacteria were screened. Phylogenetic analysis showed that 22 species of fluorine-tolerant bacteria were isolated from the sediments, belonging to 3 phyla, 5 classes, 9 orders, 12 families and 18 genera. The diversity of fluorine-tolerant bacteria was abundant in the sediments. The evaluation of plate growth assay showed that 14 strains were resistant to 50 mmol/L NaF, and 5 strains were resistant to 200 mmol/L NaF. The 5 strains of high-fluoride tolerant bacteria were distributed in 4 genera and derived from different samples, indicating that there were high-fluoride tolerant bacteria in sediments from different regions of the Mangrove protection center in Dongzhai Port. Bacterial growth curve was monitored under fluorine stress, the results showed that Agrobacterium salinitolerans 3-2-2 3 grow well under 200 mmol/L NaF, and was selected as the object for further study. Sequence-specific primers PCR showed that Agrobacterium salinitolerans 3-2-2-3 had a fluorine-tolerant gene crcB gene. Protein spectra revealed that Agrobacterium salinitolerans 3-2-2-3 could express new protein bands under F? induction. The protein bands may be used as ionophores for self-detoxification. In conclusion, The sediment of Mangrove protection center in Dongzhai Port, Hainan Province contain abundant fluorine-tolerant bacteria, and Agrobacterium salinitolerans 3-2-2-3 with the capability of high fluorine tolerance. The mechanism of fluoride tolerance and the production of fluorometabolite need further exploring.