假单胞菌BP16的分离鉴定及其植物促生性状和效应

Isolation and identification of Pseudomonas sp. BP16 and its plant growth-promoting traits and effects

摘要:

【背景】Pseudomonas最突出的植物促生性状是可抑制植物病原微生物，但其它植物促生性状报道相对较少。【目的】明确Pseudomonas sp. BP16的植物促生性状，揭示其对小麦幼苗和马铃薯的促生效应，以期为该菌株的田间应用提供理论依据。【方法】基于无机磷培养基，以涂布划线技术进行分离纯化；通过多相分类对BP16进行分类鉴定；以选择性培养基或比色法等方法对促生性状进行定性或定量分析；设置3种处理pBP16、VK、CK，分别代表施加含BP16的颗粒微生物肥料、施加不含菌的空载体颗粒、颗粒微生物肥料和空载体颗粒都不施加的空白处理，采用盆栽试验分析不同处理下的小麦和马铃薯生长性状及其根围土理化性质的变化。【结果】共分离得到41株菌；1株编号为BP16菌株的16S rRNA基因序列与P. brassicacearum subsp. neoaurantiaca的相似性最高(99.38%)，但一些生理生化特征如明胶液化存在一定的差异；BP16菌株的解磷酸钙-磷能力最强，其发酵液中水溶性磷含量可达67.15 μg/mL菌液，而且该菌具有固氮能力、产IAA (Indole-3-acetic acid)能力(8.93 mg/L)、产铁载体能力(D/d为2.46)、ACC脱氨酶活性，同时能够抑制植物病原菌马铃薯晚疫病病原菌、亚麻枯萎病病原菌和向日葵菌核病病原菌，其抑菌率分别为76.19%、32.00%和22.22%；pBP16相比VK和CK处理，显著提高了小麦的株高、根长、叶绿素含量以及干重(提高约5.29%?90.90%)，根围土速效磷和速效氮含量也显著提高，提高约8.63%?83.81%；同时，pBP16较VK和CK处理的单株产量以及根围土速效磷都有极显著的提高，而速效氮水平高于CK。【结论】菌株BP16为P. brassicacearum的一个新亚种，具有多种植物促生性状，对植物促生效应良好，可作为植物促生菌剂用菌种、具有良好的应用前景。

Abstract:

[Background] Pseudomonas is well known to inhibit plant pathogenic microorganisms. However, other plant growth-promoting traits are less reported. [Objective] To characterize the plant growth-promoting traits of Pseudomonas sp. BP16, and reveal its growth promoting effect on wheat seedling and potato. [Methods] The strain was isolated through spread and streak plating on medium of inorganic-phosphorus. We identified the taxonomic position based on polyphasic taxonomy and characterized plant growth-promoting traits on selective media or colorimetry. Wheat and potato were plot planted with 3 treatments, the first adding fertilizer containing BP16, second adding null carrier without inoculant, and third not adding any of them. [Results] 16S rRNA gene sequence of BP16 showed the highest similarity to that of P. brassicacearum subsp. neoaurantiaca (99.38%), and yet there were some major differences in physiochemical characters between them. Beside nitrogen-fixation, BP16 also possessed strong capabilities of Ca-phosphate-solubilizing (water-soluble phosphorus in fermentation solution reached 67.15 μg/mL), and production of indole-3-acetic acid (8.93 mg/L), siderophore (2.46 of D/d) and 1-aminocyclopropane-1-carboxylate deaminase. Additionally, BP16 remarkably inhabited the potato late blight, flax fusarium wilt and sunflower sclerotinia pathogens with inhibitory rates of 76.19%, 32.00% and 22.22%, respectively. Compared with the controls, wheat inoculated by BP16 increased plant height, root length, chlorophyll content and biomass. The content of rhizospheric available phosphorus and nitrogen also increased by the range from 8.63% to 83.81%. BP16 significantly enhanced the potato yield. [Conclusion] BP16 represents a new subspecies of P. brassicacearum and has multiple plant growth promoting traits. It can be used as a plant growth promoting agent.