Myxobacterium resources in Ordos Plateau: distribution and antagonistic activity against Phytophthora infestans

Abstract:

[Background] Myxobacteria are a group of prokaryotes producing abundant metabolites with novel structures, which endow myxobacteria with antimicrobial and antitumor activities.Phytophthora infestans is the pathogen causing potato late blight and has a destructive effect on potato production. The distribution of myxobacteria in Ordos Plateau as a special habitat and the antagonistic activity of these myxobacteria against P. infestans remain unclear. [Objective] To investigate the distribution of culturable myxobacteria and their antagonistic activity against P. infestans in the Ordos Plateau area, so as to lay a foundation for the use of myxobacteria in the prevention and control of potato late blight. [Methods] In this study, 46 soil samples were collected from Ordos Plateau of Inner Mongolia, from which myxobacteria were isolated and identified. The correlations of the distribution of myxobacteria with soil types, vegetation types, and environmental factors were determined, and the antagonistic activities of myxobacterial strains against P. infestans were examined. [Results] The soil in this area was dry and had poor fertility. Among the 191 strains cultured, 102 strains were purified, of which 65 strains were identified, belonging to 9 species of 5 genera, including Myxococcus fulvus, M. virescens, Corallococcus exiguus, C. interemptor, C. coralloides, Pyxidicoccus fallax, Archangium minus, Ar. gephyra, and Cystobacter fuscus. The dominant genus was Myxococcus, and the dominant species were M. fulvus and M. virescens. Myxobacteria were mainly distributed in fluvo-aquic soils and aeolian soils, while abundant rare species of myxobacteria were mainly distributed in sierozems and castano-cinnamon soils. Myxobacteria were the most common in woodland, which was followed by cultivated land, grassland, and wasteland. Among the isolated myxobacterial strains, 89.40% showed antagonistic effects on P. infestans. All the identified species had antagonistic strains, and M. fulvus was the dominant species with high resistance to P. infestans. [Conclusion] There are abundant myxobacterium resources in Ordos Plateau, and most myxobacterial strains in this area have antagonistic activity against P. infestans. This study lays a foundation for the development of novel agents from myxobacteria for the biocontrol of potato late blight.