Characterization and antipathogenic activity of Streptomyces europaeiscabiei F5 from the rhizosphere of pigeon pea

Abstract:

[Background] Pigeon pea (Cajanuscajan) is a medicinal plant with a variety of pharmacological activities. Considering the limited understanding and research on actinomycetes in the rhizosphere of pigeon pea, it is necessary to study their application and development potential. [Objective] An actinomycete strain with broad-spectrum antagonistic activity against plant pathogens and common pathogens was screened out from the rhizosphere soil of pigeon pea. The taxonomic status, metabolites and possible biosynthetic pathways were identified to provide data support for the development and application of the strain. [Methods] With 7 plant pathogenic fungi and 8 common pathogens as the indicators, plate confrontation method and filter paper diffusion method were used to screen out the actinomycete strain with broad-spectrum antagonistic activity. The selected strain was identified based on morphological characteristics and phylogenetic tree, and the secondary metabolites of the strain were detected by UPLC-Q-Exactive high-resolution mass spectrometry and UPLC-MS/MS. The polyketide synthaseⅠ(PKS-Ⅰ) and non-ribosonmal peptide synthetase (NRPS) genes of the strain were amplified by PCR to clarify the biosynthetic pathways of the antimicrobial substances. [Results]The actinomycete F5 with broad-spectrum antagonistic activity was screened out and identified as Streptomyces europaeiscabiei. The strain was able to produce active metabolites like geldanamycin and emodin. The genes encoding PKS-Ⅰand NRPS were presented in strain F5. [Conclusion] Streptomyces europaeiscabiei F5 from the rhizosphere of pigeon pea is isolated and identified for the first time. It has broad-spectrum antagonistic activity and can produce antimicrobial substances like geldanamycin and emodin, thus demonstrating great application potential in agriculture and medicine and worth of further research.