南通沿海滩涂耐盐植物重金属抗性内生细菌的筛选及生物多样性

Isolation and biodiversity of heavy metal tolerant endophytic bacteria from halotolerant plant species located in coastal shoal of Nantong

【目的】沿海滩涂耐盐植物重金属抗性内生细菌的筛选及其促生长潜在能力的研究有助于我们获得一些能够耐受并促进耐盐植物在被Cd2+、Pb2+、Hg2+、Cu2+,Zn2+等重金属离子污染的贫瘠的沿海滩涂上正常生长的菌株,达到既能够利用广袤的滩涂生物资源产生经济价值又能够净化生态环境的目的。【方法】以江苏南通沿海滩涂地区的4种耐盐植物为材料,采用稀释平板涂布法从中分离得到45株内生细菌,从中挑取23株代表性的菌株,对其进行抗重金属Cu2+、Pb2+、Cd2+、Zn2+,Hg2+的活性筛选;固氮、解磷、吲哚乙酸(IAA)的产生、1-氨基环丙烷-1-羧酸(ACC)脱氨酶活性等促生指标以及NaCl耐受能力的筛选。【结果】发现分离所得的大多数细菌能够耐受高浓度的Cu2+以及Pb2+,但是对Cd2+、Zn2+,Hg2+的耐受能力则较弱;26.1%的细菌具有固氮能力,21.7%的细菌具有解磷能力,60.9%的细菌能够产生IAA,39.1%的细菌含有ACC脱氨酶。对他们进行16S rRNA基因鉴定后发现,他们分属于芽胞杆菌属(Bacillus)、喜盐芽胞杆菌属(Halobacillus)、海洋芽胞杆菌属(Oceanobacillus)、微小杆菌属(Exiguobacterium)、沙雷氏菌属(Serratia)、短波单胞菌属(Brevundimonas)、弧菌属(Vibrio)、葡萄球菌属(Staphylococcus)共8个属,显示了丰富的多样性。其中菌株KLBMP 2432以及菌株KLBMP 2447为潜在的新种。【结论】沿海滩涂地区的耐盐植物内生细菌具有丰富多样的生物多样性以及促生长能力,且存在潜在的新种资源,并对重金属Cu2+,Pb2+具有较强的抗性。

[Objective] We isolated and identified endophytic bacteria from halotolerant plants collected from coastal shoal of Nantong and investigated their heavy-metal tolerance and plant growth promoting potential.[Methods] In total 45 strains were obtained from 4 halotolerant plants and 23 representative isolates were selected to detect their tolerance against NaCl and heavy metals of Cu2＋,Pb2＋,Cd2＋,Zn2＋,Hg2＋;plant growth promoting index of nitrogen fixation,phosphate solubilization,indoleacetic acid（IAA） production and 1-aminocyclopropane-1-carboxylic acid（ACC） deaminase.[Results] Most of the isolates could grow under high consistency of Cu2＋ and Pb2＋.Of the bacteria 26.1% had the ability of nitrogen fixation,21.7% of phosphate solubilization,60.9% of IAA production and 39.1% of ACC deaminase activity.The results of 16S rRNA sequencing show that they belonged to the genera of Bacillus,Halobacillus,Oceanobacillus,Exiguobacterium,Serratia,Brevundimonas,Vibrio and Staphylococcus.Among them,strains KLBMP 2432 and KLBMP 2447 were potential novel species.[Conclusion] The halotolerant plants located in the area of coastal shoal contain a variety of endophytic bacteria as well as the source of novel taxa.Some of them had the ability of plant growth promoting and high resistance against heavy-metal Cu2＋ and Pb2＋.