1. Rhizobacterial colonization of bermudagrass by Bacillus spp. in a Marvyn loamy sand soil.
- Author
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Coy, Richard Murphey, Held, David W., and Kloepper, Joseph W.
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BIOFERTILIZERS , *BACILLUS pumilus , *BACILLUS (Bacteria) , *TURF management , *EPIPHYTES , *MICROBIAL inoculants , *RHIZOBACTERIA , *BERMUDA grass , *SIDEROPHORES , *EPIPHYTIC bacteria - Abstract
Rhizobacterial inoculants have been previously shown to demonstrate growth promotion in bermudagrass, yet mechanisms for growth promotion and colonization of bermudagrass are unknown. Using rifampicin-resistant strains of Bacillus spp., colonization and persistence of bacteria were assessed under field conditions in the rhizoplane, rhizosphere, endorhiza, and endophytic phyllosphere. Strains of Bacillus pumilus and B. sphaericus were determined to have nitrogenase and phosphate solubilization activity and to produce siderophores. These results showed differences between strains of the same species, and phosphate solubilization was greatest under alkaline conditions. The characteristics of the rhizobacterial strains provide greater insights into the growth promotion demonstrated in bermudagrass. All bacterial strains tested were detectable in plant and soil within 24 h after inoculation and persisted through 12 week post inoculation. Colonization occurred on both external and internal plant structures, but was typically higher in rhizoplane and rhizosphere samples. Populations remained stable for 2 week after inoculation with drastic declines occurring after 6 week. Bacillus sphaericus was the most prolific colonizer, having the greatest population density per sample and least drastic population decline 12 week after inoculation. These results provide better understanding of plant-microbe-interactions in amenity grasses and can aid in determining application frequencies and intervals of biostimulants for turfgrass management. Beneficial characteristics of rhizobacteria may explain why inoculation of grass results in growth promotion. Colonization and persistence in grass was determined using antibiotic-resistant mutants. Unlabelled Image • Rhizobacterial strains demonstrated nitrogenase activity. • Rhizobacterial strains solubilized phosphate under acidic and basic conditions. • Rhizobacterial strains produced siderophores on media. • Rhizobacterial strains persist 12 wk in grass from a single inoculation. • Rhizobacterial strains colonized endophytic and epiphytic plant tissues and soil. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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