Antagonistic Mechanisms and Culture Conditions of Isolated Microbes Applied for Controlling Large Patch Disease in Zoysiagrass

Abstract

Our previous report demonstrated successful isolation of soil-borne bacteria that suppressed the potential of Rhizoctonia solani AG2-2 (IV) causing turfgrass large patch disease when applied to Korean lawngrass (Zoysia japonica). The current study aimed to uncover the mechanisms of this antagonism of Rhizoctonia solani and to define culture conditions for the isolated microbes. We found that two Bacillus isolates, I-009 and FRIN-001-1 strains, produced cellulase and siderophore, but not chitinase, while the Pseudomonas YPIN-022 strain was found to release only siderophore, implying that three antagonistic bacteria commonly interrupt Fe uptake by the large patch pathogen. The I-009 and FRIN-001-1 isolates grew best at 35 and 30°C in growth medium of pH 5 to 8 for 32 and 28 h, respectively, while optimum growth for the YPIN-022 strain was found at 35°C at pH 5 to 9 for 24 h. Good growth of I-009 and YPIN-022 over 24 h was obtained in M9 minimal medium supplemented with 1% sucrose, 0.5% yeast extract and 0.1% potassium chloride. FRIN-001-1 grew well in M9 medium with 1% mannitol, 0.5% yeast extract and 0.1% potassium phosphate dibasic.

Biocontrol of Large Patch Disease in Zoysiagrass (Zoysia japonica) by Bacillus subtilis SA-15: Identification of Active Compounds and Synergism with a Fungicide

“…It was determined on a medium consisting of 15.0 g•L −1 pancreatic digest of casein, 5.0 g•L −1 papaic digest of soybean, 5.0 g•L −1 NaCl, 15.0 g•L −1 agar, and 10.0 g•L −1 carboxymethyl cellulose. SA-15 cells were inoculated on this medium and incubated at 30 • C for 48 h, and then, cellulase activity was determined based on the clear zone with 0.1% Congo red solution [7].…”

“…Microorganisms with cellulase activity not only mineralize organic matter in the root zone but also inhibit the mycelial growth of Oomyetes because of degradation of fungal mycelia [7]. Cell wall lytic (CWL) enzymes include cellulase, chitinase, and β-glucanase, and may degrade or cleave main constituents of mycelial cell walls [7]. In addition, lipopeptides such as bio-surfactant, inturins and fengycin are important antifungal products produced from microbes [7][8][9][10].…”

“…Cell wall lytic (CWL) enzymes include cellulase, chitinase, and β-glucanase, and may degrade or cleave main constituents of mycelial cell walls [7]. In addition, lipopeptides such as bio-surfactant, inturins and fengycin are important antifungal products produced from microbes [7][8][9][10]. Many researchers have screened potential bacteria producing CWLs or antifungal compounds for biocontrol of plant diseases [7][8][9][10].…”

“…In addition, lipopeptides such as bio-surfactant, inturins and fengycin are important antifungal products produced from microbes [7][8][9][10]. Many researchers have screened potential bacteria producing CWLs or antifungal compounds for biocontrol of plant diseases [7][8][9][10]. As an endophytic bacterium, B. subtilis has been reported to have CWL activities and produce antifungal metabolites [7,11].…”

“…Many researchers have screened potential bacteria producing CWLs or antifungal compounds for biocontrol of plant diseases [7][8][9][10]. As an endophytic bacterium, B. subtilis has been reported to have CWL activities and produce antifungal metabolites [7,11].…”