Biocontrol Activity of Volatile-Producing Bacillus megaterium and Pseudomonas protegens Against Aspergillus and Penicillium spp. Predominant in Stored Rice Grains: Study II

• Published in: Mycobiology Vol. 46; no. 1; pp. 52 - 63
• Main Authors: Mannaa, Mohamed, Kim, Ki Deok
• Format: Journal Article
• Language: English
• Published: Korea (South) Taylor & Francis 01.01.2018; Taylor & Francis Group; 한국균학회
• Subjects: Antifungal activity; Aspergillus; Bacillus megaterium; bacterial volatiles; biological control; Penicillium; Pseudomonas protegens; 생물학; Antifungal activity; Aspergillus; bacterial volatiles; Penicillium; Pseudomonas protegens; biological control; Bacillus megaterium
• ISSN: 1229-8093; 2092-9323
• DOI: 10.1080/12298093.2018.1454015

In our previous studies, KU143 KU313, and AS15 have been shown to be antagonistic to in stored rice grains. In this study, the biocontrol activities of these strains were evaluated against , , and , which are predominant in stored rice grains. and antifungal activities of the bacterial strains were evaluated against the fungi on media and rice grains, respectively. The antifungal activities of the volatiles produced by the strains against fungal development and population were also tested using I-plates. In tests, the strains produced secondary metabolites capable of reducing conidial germination, germ-tube elongation, and mycelial growth of all the tested fungi. In tests, the strains significantly inhibited the fungal growth in rice grains. Additionally, in I-plate tests, strains KU143 and AS15 produced volatiles that significantly inhibited not only mycelial growth, sporulation, and conidial germination of the fungi on media but also fungal populations on rice grains. GC-MS analysis of the volatiles by strains KU143 and AS15 identified 12 and 17 compounds, respectively. Among these, the antifungal compound, 5-methyl-2-phenyl-1H-indole, was produced by strain KU143 and the antimicrobial compounds, 2-butyl 1-octanal, dimethyl disulfide, 2-isopropyl-5-methyl-1-heptanol, and 4-trifluoroacetoxyhexadecane, were produced by strain AS15. These results suggest that the tested strains producing extracellular metabolites and/or volatiles may have a broad spectrum of antifungal activities against the grain fungi. In particular, KU143 and AS15 may be potential biocontrol agents against and spp. during rice grain storage.