Screening and identification of antagonistic and plant-growth promoting endophytic bacteria from Seabuckthorn nodules

Abstract:

[Background] Endophytic bacteria can produce antagonistic and plant-growth promoting substances, which can not only inhibit host plants attacked by pathogens, but also promote the growth of plants. The endophytic bacteria from Seabuckthorn nodules are a kind of symbiotic microorganism. Studying endophytic bacteria with antagonistic and plant-growth promoting activity, which could be used as the basis of bacterial manure research. [Objective] To screen and identify efficient endophytic bacteria from Seabuckthorn nodules and study its activity of antagonistic and plant-growth promoting substances. [Methods] Antagonistic endophytes from Seabuckthorn nodules were screened by double agar layer piaque technique, agar diffusion assay, confrontation culture and oxford cup culture in vitro. The ability of indole acetic acid secretion were detected through the Salkowski colorimetric method, the production of siderphore were measured through the blue plate assay and phosphate solubilization were detected through Mo-Santispetrophotography method. The effects of growth promotion on cucumber seedlings were studied by using the fermentation broth of strain SR308. In addition, strain TT201 and SR308 were identified by morphological, culture, physiological and biochemical tests and 16S rRNA gene sequence analysis. [Results] Among 131 strains, 9 strains displayed the antagonistic and plant-growth promoting activity, especially strain TT201 displayed high antagonistic activity and broad antimicrobial spectrum; strain SR308 displayed high growth promoting activity. Pos tests showed that cucumber growth index treatment with SR308 fermentation broth were promoted significantly. Strain TT201 was identified as Brevibacillus laterosporus; strain SR308 was identified as Bacillus mycoides. [Conclusion] Two endophytic bacteria from Seabuckthorn nodules with antagonistic and plant-growth promoting activity are possible to be further developed as an excellent strain for microbial fertilizer and fungicide.