具有ACC脱氨酶活性的绞股蓝内生细菌的分离鉴定及其抑菌促生作用

采用富集筛选法从绞股蓝根中筛选得到6株具有ACC脱氨活性的细菌，其中菌株JDG-6、JDG-7、JDG-14、JDG-16、JDG-23均具有较强的分泌铁载体能力，但菌株JDG-32没有产铁载体能力。抑菌试验结果显示，菌株JDG-6、JDG-7、JDG-14和JDG16对一种或多种供试菌有抑菌作用，其中菌株JDG-14能抑制大肠埃希菌、藤黄八叠球菌和白色念球菌的生长。促生试验表明，菌株JDG-6、JDG-7和JDG-14均能促进水稻幼苗根的伸长，其中菌株JDG-14的促生作用最为明显，与对照组相比水稻幼苗的根长和根鲜重分别增长了26%和21%。通过形态特征观察、生理生化试验以及16S rDNA序列分析，菌株JDG-6、JDG-7、JDG-16和JDG-23属于假单胞杆菌属（Pseudomonas），菌株JDG-14为木糖葡萄球菌（Staphylococcus xylosus），而菌株JDG-32为枯草芽胞杆菌（Bacillus subtilis）。菌株JDG-6、JDG-7和JDG-14均具有ACC脱氨酶活性和抑菌活性的促生菌，具有农业应用潜力。

Isolation, Characterization, Antimicrobial & Plant Growth Promoting Activities of ACC Deaminase Containing Endophytic Bacteria from Gynostemma pentaphyllum Makino

A total of six endophytic bacterial strains possessing ACC deaminase activity were isolated from the roots of Gynostemma pentaphyllum adopted with enrichment method, among them strains JDG-6, JDG-7, JDG-14, JDG 16 and JDG-23 had the ability to excrete siderophores, but strain JDG 32 had not. The results of microbe inhibition assay showed that the strains JDG-6, JDG-7, JDG-14 and JDG 16 displaying antimicrobial activities against one or multiple tested organism, among them strain JDG 14 significantly inhibited the growth of E. coli, Sarcina luteus, and Candida albicans. The growth experiment suggested that all strains JDG-6, JDG-7, and JDG-14 could promote the root extension of rice seedlings, especially strain JDG-14 the growth promotion was among the most, with the root length increased by 26%, and root fresh weight by 21% respectively as compared to the control groups. Based on the morphological, physiological, biochemical features observation as well as 16S rDNA sequences analysis, strains JDG-6, JDG-7, JDG-16 and JDG-23 belonged to the genus of Pseudomonas, JDG-14 Staphylococcus xylosus, and JDG-32 Bacillus subtilis. All strains JDG-6, JDG-7, and JDG-14 were growth promoter bacteria possessing ACC deaminase and antimicrobial activities, they possessed agricultural application potential.