薄层菌L28的分离鉴定及其对马铃薯快繁苗生长的促进作用

Isolation and identification of Hymenobacter sp. L28 for rapid propagation potato plantlet

摘要:

【背景】薄层菌(Hymenobacter)是不利生长环境(如营养贫瘠的荒漠土壤)中的优势细菌类群，目前对该类菌的研究集中于分离鉴定，尚无对植物促生相关的研究报道。【目的】从浑善达克荒漠土壤分离鉴定细菌，并分析菌株对马铃薯快繁苗生长的影响。【方法】基于选择性培养基，以涂布划线方法进行细菌的分离培养；扩增16S rRNA基因并测序，分析序列相似性和系统发育，并参考形态和生理生化特征对菌株进行初步分类鉴定；以选择性培养基或比色法等方法对纯培养物进行促生性状分析；采用MS固体培养基分析菌株对马铃薯快繁苗生长的影响。【结果】分离得到一株编号为L28的细菌，其16S rRNA基因序列与Hymenobacter koreensis GYR3077T的相似性最高，为96.46%；菌株L28具有固氮、解磷酸钙-磷、解植酸磷-磷、产吲哚-3-乙酸(indole-3-acetic acid，IAA) (7.51 mg/L)、产铁载体(D/d为2.47)和有1-氨基环丙烷羧酸(1-amino-cyclopropane-1-carboxylic acid，ACC)脱氨酶活性等多种植物促生特性；接种L28相比不接种显著提高了马铃薯快繁苗的节点数、株高、根长、茎长、根干重和茎干重(提高了28.57%?234.94%)；移栽后，接种菌株L28相比不接种显著提高了种薯数量和重量，分别提高了40%和181.87%。【结论】分离自浑善达克荒漠土壤的菌株L28属于Hymenobacter，具有多种植物促生特性，能显著促进马铃薯快繁苗生长及其移栽后种薯的形成，可作为植物促生菌种，在马铃薯生产中具有良好应用前景。

Abstract:

[Background] Hymenobacter is dominant in bacteria in adverse environment (e.g. desert soil with nutrition poor). The research on this group has focused on the isolation and identification, yet until now there no the plant growth promotion is studied. [Objective] To isolate and identify bacteria from the soil of Desert Hunshandake, and evaluate the effect on the growth of potato rapid propagation plantlet. [Methods] On selective media, spread and streak plating was employed to isolate. For the primary taxonomic identification, 16S rRNA gene was PCR amplified and sequenced and the similarity and phylogeny were analyzed, combined with the basic morphological, physiobiochemical characteristics analysis. The plant growth-promoting traits were characterized on selective media or colorimetry. MS media was used to assay the effect on the growth of potato rapid propagation plantlet. [Results] A bacterial strain, designated as L28, was obtained in this study. Strain L28 showed the highest 16S rRNA gene sequence similarity of 96.46% with Hymenobacter koreensis GYR3077T. The strain possessed multiple plant growth-promoting traits, including nitrogen fixation, Ca3(PO4)2-P dissolving, phytate-P degrading, indole-3-acetic acid (IAA) producing (7.51 mg/L), siderophore producing (D/d=2.47) and 1-amino-cyclopropane-1-carboxylic acid (ACC) deaminase active. Compared to the uninoculated, the inoculation of L28 markedly increased the plantlet’s node number, height, root length, stem length, dry weight of root, and dry weight of stem with the increments of 28.57%?234.94%; for transplanted plant, the inoculation of L28 significantly elevated the number and weight of potato tuber seed with the increments of 40% and 181.87%, respectively. [Conclusion] Bacterial isolate L28 from the soil of Desert Hunsandake belongs to the genus Hymenobacter, and has multiple plant growth promoting traits. The strain markedly promotes the growth of rapid propagation potato plantlet and the development of potato tuber. It can be used as a plant growth promoting agent and has important prospect in potato production.