具ACC脱氨酶活性的碱蓬内生细菌的分离、鉴定及其生物学特性

Isolation, identification and characterization of ACC deaminase-containing endophytic bacteria from halophyte Suaeda salsa

摘要:

摘要：【目的】具有1-氨基环丙烷-1-羧酸（ACC）脱氨酶活性的盐生植物碱蓬内生细菌的分离及生物学特性的研究有助于探索内生细菌与宿主植物耐盐性的关系。【方法】采用研磨法从健康碱蓬植株的根、茎、叶中分离具有ACC脱氨酶活性的碱蓬内生细菌，根据形态特征、生理生化、API鉴定系统和16S rRNA对菌种进行鉴定，并分别测定了菌株产ACC脱氨酶、铁载体、吲哚乙酸、赤霉素、脱落酸、蛋白酶及溶磷、固氮和拮抗病原菌的特性。【结果】将分离得到的内生细菌LP11、 SS12、 TW1和TW2分别鉴定为栖稻假单胞菌（Pseudomonas oryzihabitans）、假单胞菌（Pseudomonas sp.）、成团泛菌（Pantoea agglomerans）和恶臭假单胞菌（Pseudomonas putida），4株菌除具有较高的ACC脱氨酶活力之外，还可不同程度地产生铁载体、吲哚乙酸、赤霉素和脱落酸，且均有溶磷作用，但无固氮能力及蛋白酶活力，唯有菌株SS12对萝卜枯萎病菌（Fusarium oxysporum f. sp. conglutinans）和黄瓜枯萎病菌（F. oxysporum f. sp. cucumerinum）具有拮抗作用。【结论】从盐生植物碱蓬中分离到的假单胞菌属和泛菌属内生细菌，具有丰富多样的生物学特性。

关键词:关键词：碱蓬;ACC脱氨酶;内生细菌;鉴定

Abstract:

Abstract: [Objective] We Isolated and characterized 1-aminocyclopropane-1-carboxylate (ACC) deaminase-containing endophytic bacteria from halophyte Suaeda salsa to understand the interactions between endophytes and halophyte. [Methods] ACC deaminase-containing endophytic bacteria were isolated from root, stalk and leaf of Suaeda salsa and were identified based on morphological, physiological-biochemical properties, API and 16S rRNA sequence analysis. Isolates were evaluated for their ACC deaminase, antifungal, protease activity, siderophores and phytohormones, such as indole-3-acetic acid, gibberellic acid and abscisic acid production, as well as atmospheric nitrogen fixation and phosphate solubilization. [Results] Four ACC deaminase-containing endophytic bacteria strains named as LP11, SS12, TW1 and TW2 were isolated and identified as Pseudomonas oryzihabitans, Pseudomonas sp., Pantoea agglomerans and Pseudomonas putida respectively. All the strains possessed the phosphate-solubilizing ability and could produce siderophores and phytohormones more or less. None of them could fix atmospheric nitrogen or produce protease. Only strain SS12 showed antagonism against two phytopathogenic fungi viz Fusarium oxysporum f. sp. conglutinans and F. oxysporum f. sp. cucumerinum. [Conclusion] ACC deaminase-containing endophytic bacteria of Pseudomonas sp. and Pantoea sp. isolated from halophyte Suaeda salsa have abundant biological characteristics related to plant growth promotion, stress homeostasis regulation and biocontrol activity.

Key words:Keywords: Suaeda salsa; ACC deaminase; endophytic bacteria; identification