Research articles
ScienceAsia 50 (2024):ID 2024096 1-10 |doi:
10.2306/scienceasia1513-1874.2024.096
Characterization of a multifunctional biocontrol strain,
Bacillus subtilis CH6, and its antagonistic mechanism against
Pyricularia oryzae causing rice blast disease
Natthaphon Khongkhaluonga,b, Pisut Yotbuntuengc, Patchanee Auncharoenc, Umaporn Uawisetwathanac, Vanicha Vichaic, Thanasak Lomthongd, Chatsuda Sakdapetsiria,b,*
ABSTRACT: Rice blast disease, caused by Pyricularia oryzae, is economically significant and reduces rice productivity.
Chemical control methods have proven successful and are widely adopted for managing rice blast disease, but this
practice is detrimental to the ecosystem and living creatures. Hence, research on environmentally friendly alternatives
such as employing microorganisms to manage plant diseases has attracted significant attention. This study investigated
the underlying mechanisms of Bacillus subtilis CH6 antagonistic activity against P. oryzae. The antagonistic activity
of this strain was demonstrated by the dual culture assay, in which fungal growth was inhibited by 86.23%. The
bacteria exhibited capacities to produce cell wall degradation enzymes, antifungal secondary metabolites, and volatile
organic compounds (VOCs). Furthermore, strain CH6 displayed characteristics of plant growth-promoting bacteria
including the ability to produce siderophores, indole-3-acetic acid (IAA) (3.27?0.04 ?g/ml), nitrogen fixation activity,
as well as phosphate solubilizing activity. The evaluation of bacterial culture extracts indicated the presence of bioactive
metabolites which exerted inhibitory activity against both fungal spore germination and mycelial growth, with MIC90
values of 0.375 and 60 mg/ml, respectively. Chemical analysis using ultra-high performance liquid chromatographyhigh resolution tandem mass spectrometry (UHPLC-MS/MS) confirmed the production of fengycins and surfactins
which could be responsible for the antagonistic activity of B. subtilis CH6 against P. oryzae. This investigation provides
new insights into the versatility of B. subtilis CH6 and its capability of controlling P. oryzae as a promising candidate for
the development of dual-functioned biocontrol products.
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a |
Department of Plant Pathology, Faculty of Agriculture at Kamphaeng Saen, Kasetsart University Kamphaeng Saen
Campus, Nakhon Pathom 73140 Thailand |
b |
Biodiversity Center Kasetsart University, Bangkok 10900 Thailand |
c |
National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology
Development Agency (NSTDA), Thailand Science Park, Pathum Thani 12120 Thailand |
d |
Division of Biology, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi,
Pathum Thani 12110 Thailand |
* Corresponding author, E-mail: Chatsuda.sak@ku.ac.th
Received 15 Dec 2023, Accepted 1 Sep 2024
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