Selection and Characterization of Bacillus licheniformis MH48 for the Biocontrol of Pine Wood Nematode (Bursaphelenchus xylophilus)

Abstract

Pine wilt disease (PWD) caused by pine wood nematode, Bursaphelenchus xylophilus, has become the most serious threat to pine trees in Korea. This study was subjected to investigate effective biological control agent against PWD. To select nematocidal bacteria against PWD, Bacillus licheniformis MH48 was selected among five bacteria due to its high nematocidal potential. B. licheniformis MH48 was tested for cell growth and protease activity to evaluate its nematicidal potential. In the B. licheniformis MH48, cell numbers were highest three days after incubation, while protease activity was highest after seven days. In the effect of different concentrations of B. licheniformis MH48 culture broth against B. xylophilus, 20% concentration of culture broth showed approximately 80% of pine wood nematode mortality compared to the control. Especially, pine wood nematode's cuticle layers were degraded two days after treatment of B. licheniformis MH48 culture broth. The present study suggests that B. licheniformis MH48 can be one of the potential biocontrol candidates against pine wood nematode due to its ability to produce protease.

The Control of Fusarium Root Rot and Development of Coastal Pine (Pinus thunbergii Parl.) Seedlings in a Container Nursery by Use of Bacillus licheniformis MH48

“…The bacterial strains of B. licheniformis MH48 were isolated from rhizosphere soil in a coastal area of Korea [25,26,39,41]. This bacterial strain was obtained from the laboratory of soil microbiology, Chonnam National University, Korea.…”

“…The direct promotion of plant growth by PGPR provides the plant with phytohormones [24][25][26], which facilitate the uptake of nutrients from the soils [24,25,27,28] and help establish a symbiosis with rhizobia or mycorrhiza [29]. The indirect promotion of plant growth occurs when PGPR lessen or prevent the deleterious effects of pathogenic organisms [30][31][32][33][34][35][36][37], nematodes, and insects [38][39][40] by producing antagonistic substances, such as hydrolytic enzymes, including chitinases, glucanases, proteases, and lipases. The Bacillus species is one of the most important microorganisms in PGPR and is isolated from rhizosphere soil [25,26,34,37,39,41].…”

“…The indirect promotion of plant growth occurs when PGPR lessen or prevent the deleterious effects of pathogenic organisms [30][31][32][33][34][35][36][37], nematodes, and insects [38][39][40] by producing antagonistic substances, such as hydrolytic enzymes, including chitinases, glucanases, proteases, and lipases. The Bacillus species is one of the most important microorganisms in PGPR and is isolated from rhizosphere soil [25,26,34,37,39,41]. The benefits of Bacillus licheniformis strains include the production of plant hormones, such as auxin and gibberellin, nitrogen fixation, and the solubilization of inorganic phosphate, which lead to increased Plant growth-promoting rhizobacteria (PGPR) are beneficial native soil bacteria that are an environmentally sound way of increasing plant yields by facilitating plant growth through either a direct or an indirect mechanism [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40].…”

“…The Bacillus species is one of the most important microorganisms in PGPR and is isolated from rhizosphere soil [25,26,34,37,39,41]. The benefits of Bacillus licheniformis strains include the production of plant hormones, such as auxin and gibberellin, nitrogen fixation, and the solubilization of inorganic phosphate, which lead to increased Plant growth-promoting rhizobacteria (PGPR) are beneficial native soil bacteria that are an environmentally sound way of increasing plant yields by facilitating plant growth through either a direct or an indirect mechanism [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. The direct promotion of plant growth by PGPR provides the plant with phytohormones [24][25][26], which facilitate the uptake of nutrients from the soils [24,25,27,28] and help establish a symbiosis with rhizobia or mycorrhiza [29].…”

“…The indirect promotion of plant growth occurs when PGPR lessen or prevent the deleterious effects of pathogenic organisms [30][31][32][33][34][35][36][37], nematodes, and insects [38][39][40] by producing antagonistic substances, such as hydrolytic enzymes, including chitinases, glucanases, proteases, and lipases. The Bacillus species is one of the most important microorganisms in PGPR and is isolated from rhizosphere soil [25,26,34,37,39,41].…”