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

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.