缓解花生连作障碍的根际促生菌分离及功能鉴定

Isolation and identification of peanut plant-growth promoting rhizobacteria with the potential to alleviate continuous cropping obstacle

摘要:

[目的] 长期连作障碍严重降低花生生产的产量及品质，根际促生菌可有效降解土壤中自毒化感物质、抑制植物病原菌生长及促进植物生长，从而有效缓解连作障碍问题。筛选优化具有缓解花生连作障碍能力的多功能根际益生微生物，验证其益生作用能力，为根际促生菌株在连作障碍中的应用提供理论依据及技术支持。[方法] 采集连作12年地块花生根际土壤，利用以酚酸为唯一碳源的筛选培养基获得具有酚酸自毒化感物质降解及利用能力的根际促生菌，通过16S rRNA基因测序进行系统发育分析，确定根际促生菌菌株的分类地位，并验证其对植物病原菌生长抑制能力及解磷、解钾、产植物激素吲哚乙酸能力。[结果] 从连作12年的花生发病土壤中获得7株可高效降解酚酸类自毒物质且降解底物多样的根际微生物菌株，经16S rRNA测序比对分别为克雷伯氏菌B02 （Klebsiella sp.B02）、克雷伯氏菌B07 （Klebsiella sp.B07）、克雷伯氏菌B15 （Klebsiella sp.B15）、芽孢杆菌B28 （Bacillus sp.B28）、不动杆菌P09 （Acinetobacter sp.P09）、布鲁氏杆菌VA05 （Brucella sp.VA05）、芽孢杆菌CA04 （Bacillus sp.CA04）。促生实验表明，7株高效降解菌株均可以合成吲哚乙酸，3株具有固氮能力，4株菌具有解有机磷及无机磷的能力，2株菌具有解钾的能力。拮抗实验表明，2株菌可以抑制多种植物病原菌的生长，均为芽孢杆菌属。选取Bacillus sp.B28初步验证对花生种子萌发及幼苗生长的影响，结果表明根际促生菌可显著缓解酚酸对花生种子发芽的抑制，并明显促进花生幼苗的生长。[结论] 获得多株具有降解酚酸类自毒化感物质、抑制植物病原菌生长及促进植物生长的多功能花生根际促生菌，更好地为根际促生菌在连作障碍治理中的有效应用提供菌株及技术支持。

Abstract:

[Objective] Continuous cropping obstacle reduced the production and quality of agricultural products,and application of rhizosphere beneficial microbes with the function of degrading autotoxic substances, inhibiting the growth of plant pathogen and promoting plant growth was an important strategy for suppression of continuous cropping obstacle. Screening and revealing the function of peanut plant-growth promoting rhizobacteria with the potential to alleviate soil degeneration caused by continuous cropping obstacle, would provide scientific evidence for the application in agricultural produce. [Methods] Screening high-efficiency plant growth-promoting rhizobacteria with function of degrading autotoxic substances, inhibiting the growth of plant pathogen and promoting plant growth from 12-year peanut filed with continuous cropping obstacle, and the phylogenetic analysis was performed by 16S rRNA gene sequencing to determine the taxonomic status. [Results] 7 plant growth-promoting rhizobacteria with high-efficiency in degrading autotoxic substances were isolated from the rhizosphere from 12-year continuous cropping peanut soil, and according to phylogenetic analysis, identified as Klebsiellasp. B02, Klebsiella sp. B07, Klebsiella sp. B15, Bacillus sp. B28, Acinetobacter sp. P09, Brucella sp. VA05 and Bacillus sp. CA04. The result of growth-promoting experiments indicated that 7 strains showed the ability of IAA-producing, 3 strains showed the ability of nitrogen-fixing, 4 strains showed the ability of phosphate solubilization, 2 strains showed the activity of potassium solubilizing. The result of antagonistic activity showed that 2 strains could against to plant pathogen, and belong to the specie of Bacillus genus. Bacillus sp. B28 was selected for peanut pot experiment, the results showed that strain Bacillus sp. B28 can significantly alleviate the inhibition of phenolic acid on peanut seed germination and promote the growth of peanut seedling. [Conclusion] This research screened plant growth-promoting rhizobacteria with high-efficiency in alleviate continuous cropping obstacles, provided strains and scientific evidence for the application in agricultural produce.