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

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.