产ACC脱氨酶植物根际促生菌的筛选及其对修复植物高羊茅生长的影响

摘要

以1-氨基环丙烷-1-羧酸(ACC)为唯一氮源,从石油污染的土壤中分离得到一株具有ACC脱氨酶活性的菌株D5A.该菌在以ACC为唯一氮源条件下,其ACC脱氨酶比活力为0.084 U/mg.另外,D5A还具有产生吲哚乙酸(IAA)、耐盐以及溶磷的特性.在液体培养条件下该菌株产IAA高达112 mg/L,在90 g/kg盐含量的培养基中仍能够正常生长且具有较强的溶解矿物磷能力.同时该菌对酸碱具有良好的适应性,在初始pH4～10的LB培养基中生长良好.种子发芽试验表明在3 g/kg和6 g/kg浓度NaC1的逆境条件下,该菌株能显著提高高羊茅种子的发芽率和芽长.最后,通过对其进行生理生化特性和16S rDNA序列分析,该菌株初步鉴定为克雷伯氏菌(Klebsiellasp.).%In this study,the strains with 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity were isolated from an oil-polluted soil.The ACC deaminase activity of the strain D5A was 0.084 U/mg in minimal medium containing ACC as the sole nitrogen source.In addition,D5A also had properties of producing indole acetic acid (IAA),salt tolerance and dissolving phosphorus.In liquid culture conditions,the strains produced IAA up to 112 mg/L.It was still able to grow normally in the medium of 90 g/kg salt and had a strong ability to dissolve the mineral phosphorus.The strains grew well in LB medium from the initial pH value of 4 to 10,which showed the strains had good adaptability of pH.Seed germination tests showed that the strains could significantly improve seed germination and bud of tall fescue(Festuca arundinacea) at adverse conditions of 3 g/kg and 6 g/kg NaCl.Finally,based on physiological,biochemical characteristics and 16S rDNA sequence analysis,the strains was identified as Klebsiella sp.