一株人参内生1-氨基环丙烷-1-1羧酸(ACC)脱氨酶活性细菌的筛选、鉴定及其对宿主生长的影响

Screening and identification of an endophytic bacterium with 1-aminocyclopropane-1-carboxylate deaminase activity from Panax ginseng and its effect on host growth

摘要:

摘要:【目的】从人参内生细菌中获得具有1-氨基环丙烷1-羧酸(ACC)脱氨酶活性的菌株，并进行促生效果的验证。【方法】结合初筛和复筛的方法筛选具有ACC脱氨酶活性的人参内生菌株;采用Ashby培养基和固氮酶基因验证其固氮潜能;菌碟法及钼锑抗比色法测定其解磷能力;CAS方法检测产生铁载体能力;通过室内及田间试验测定菌株对人参生长的促进作用。通过形态学、生理生化测定及16S rＲNA序列分析明确菌株的分类地位。【结果】从120株人参内生菌中获得了一株具有较高ACC脱氨酶活性的菌株JJ8-3，其酶 活性为α-酮丁酸6.7 μmol/(mg·h);且具有解磷特性、固氮潜能和产生铁载体能力;能明显促进人参种子及根部的生长;经鉴定菌株JJ8-3为荧光假单胞菌(Pseudomonas fluorescens)。【结论】获得了一株具有ACC脱氨酶活性的人参内生细菌，将为其在促进植物生长中的应用和研究奠定基础。

Abstract:

Abstract: ［Objective］ This study aimed to screen endophytic bacteria with 1-aminocyclopropane-1-carboxylate deaminase activity from Panax ginseng and test the capability of growth promotion to its host.［Methods］In total 120 endophytic bacterial strains isolated from Panax ginseng were screened for 1-aminocyclopropane-1-carboxylate deaminase activity using the qualitative and quantitative methods． The obtained strain was also tested for its ability of nitrogen fixation using the Ashby agar plates and the gene of nifH，for its ability of phosphate solubilization using the Pikovaskaia’s plates and quantitative analysis of Mo-Sb-Ascrobiology acid colorimetry，for its ability of producing siderophores using the method of Chrome azurol S detecting，and its effect on promoting growth of Panax ginseng by laboratory and field experiments． The bacterial strain with ACC deaminase was identified based on morphology，physiological and biochemical traits，and 16S rＲNA sequence analysis.［Ｒesults］The bacterial stain JJ8-3 with the ability of producing ACC deaminase activity was obtained through screening，which its ACC deaminase activity was α-ketobutyric acid 6.7 μmol/(mg·h)．Strain JJ8-3 had other traits of phosphate solubilizing，nitrogen fixation，producing siderophores，and the ability of promoting growth of Panax ginseng． Strain JJ8-3 was identified as Pseudomonas fluorescens． ［Conclusions］ Strain JJ8-3 of endophytic bacterium with ACC deaminase activity from Panax ginseng was obtained and would lay the foundation for its further study and application on plant growth promotion．