title: Bacillus amyloliquefaciens subsp. plantarum GR53, a potent biocontrol agent resists Rhizoctonia disease on Chinese cabbage through hormonal and antioxidants regulation.
abstract: The fungus Rhizoctonia solani is one of the causal agents of numerous diseases that affect crop growth and yield. The aim of this present investigation was to identify a biocontrol agent that acts against R. solani and to determine the agent's protective effect through phytohormones and antioxidant regulation in experimentally infected Chinese cabbage plants. Four rhizospheric soil bacterial isolates GR53, GR169, GR786, and GR320 were tested for their antagonistic activity against R. solani. Among these isolates, GR53 significantly suppressed fungal growth. GR53 was identified as Bacillus amyloliquefaciens subsp. plantarum by phylogenetic analysis of the 16S rDNA sequence. The biocontrol activity of B. amyloliquefaciens subsp. plantarum GR53 was tested in Chinese cabbage plants under controlled conditions. Results showed that R. solani inhibited plant growth (length, width, fresh and dry weight of leaves) by reducing chlorophyll and total phenolic content, as well as by increasing the levels of salicylic acid, jasmonic acid, abscisic acid, and DPPH scavenging activity. By regulating the levels of these compounds, the co-inoculation of B. amyloliquefaciens subsp. plantarum GR53 heightened induced systemic resistance in infected Chinese cabbage, effectively mitigating R. solani-induced damaging effects and improving plant growth. The results obtained from this study suggest that B. amyloliquefaciens subsp. plantarum GR53 is an effective biocontrol agent to prevent the damage caused by R. solani in Chinese cabbage plants.
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Sang-Mo
authors.initials: SM
authors.lastname: Kang
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea.
authors.forename: Ramalingam
authors.initials: R
authors.lastname: Radhakrishnan
authors.affiliation: School of Applied Biosciences, Kyungpook National University, Daegu, 702-701, Republic of Korea. ijlee@knu.ac.kr.
authors.forename: In-Jung
authors.initials: IJ
authors.lastname: Lee
mesh_terms: D000898:Antibiosis; D000975:Antioxidants / Q000378:metabolism*; D001407:Bacillus / Q000254:growth & development* / Q000378:metabolism; D029741:Brassica rapa / Q000382:microbiology*; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D010572:Pest Control, Biological / Q000379:methods; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology* / Q000517:prevention & control; D010937:Plant Growth Regulators / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012232:Rhizoctonia / Q000254:growth & development*; D017422:Sequence Analysis, DNA
chemical_list: D000975:Antioxidants; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D010937:Plant Growth Regulators; D012336:RNA, Ribosomal, 16S
keywords: Bacillus amyloliquefaciens subsp. plantarum GR53; Biocontrol; Chinese cabbage; Rhizoctonia solani