Molecular Detection of Antimicrobial Peptide Genes and Identification of Antifungal Compounds of Bacillus sp. against Fusarium oxysporum f. sp cubense Causing Wilt in Banana
Rajesh Kumar Ponnusamy *
Department of Plant Pathology, TNAU, Coimbatore, India.
Paranitharan Vaikuntavasan
Department of Plant Biotechnology, CPMB, TNAU, Coimbatore, India.
Rajesh Subramanian
Department of Plant Biotechnology, CPMB, TNAU, Coimbatore, India.
Kavino Mathiyazhagan
Department of Fruits Crops, HC&RI, TNAU, Coimbatore, India.
Muthulakshmi Palanisamy
Department of Plant Pathology, TNAU, Coimbatore, India.
Kamalakannan Ayyanar
Department of Plant Pathology, TNAU, Coimbatore, India.
*Author to whom correspondence should be addressed.
Abstract
Fusarium oxysporum f. sp cubense (Foc) is a serious infectious agent that causes Fusarium wilt of banana within tropical and semi-tropical regions of India. It is both necessary and critical to find an efficient biocontrol strategy to ensure banana production around the world. Twenty strains of Bacillus species from various banana rhizosphere regions were analysed using 16s rRNA and tested against Foc in vitro. Among 20 strains, B18, B4 and B7 were observed to inhibit the mycelial growth of the pathogen. The Bacillus sp strains were analysed through PCR with specific primers for the presence of antimicrobial biosynthetic genes viz., Iturin A, Iturin C, Bacillomycin A, Surfactin and Bacillomycin D. The effective strain B18 was identified as Bacillus cereus based on biochemical and 16s rRNA region. In addition to antimicrobial peptide gens, the crude antibiotic extract from strain B18 was highly effective against Foc possibly owing to the presence of diverse antifungal compounds namely, 1- Dodecene, heptadecane, Pyrrolidine, Tetradecane, 1- Hexadecanol and Nonadecane, detected and identified using Gas chromatography and Mass spectrometry (GC/MS).
Keywords: Bacillus, Fusarium oxysporum f. sp cubense, antifungal compounds, antimicrobial genes, GCMS.