title: Combinatorial effect of mutagenesis and medium component optimization on Bacillus amyloliquefaciens antifungal activity and efficacy in eradicating Botrytis cinerea.
abstract: This work is directed towards Bacillus amyloliquefaciens strain BLB371 metabolite production for biocontrol of fungal phytopathogens. In order to maximise antifungal metabolite production by this strain, two approaches were combined: random mutagenesis and medium component optimization. After three rounds of mutagenesis, a hyper active mutant, named M3-7, was obtained. It produces 7 fold more antifungal metabolites (1800AU/mL) than the wild strain in MC medium. A hybrid design was applied to optimise a new medium to enhance antifungal metabolite production by M3-7. The new optimized medium (35g/L of peptone, 32.5g/L of sucrose, 10.5g/L of yeast extract, 2.4g/L of KH2PO4, 1.3g/L of MgSO4and 23mg/L of MnSO4) achieved 1.62 fold enhancement in antifungal compound production (3000AU/mL) by this mutant, compared to that achieved in MC medium. Therefore, combinatory effect of these two approaches (mutagenesis and medium component optimization) allowed 12 fold improvement in antifungal activity (from 250UA/mL to 3000UA/mL). This improvement was confirmed against several phytopathogenic fungi with an increase of MIC and MFC over than 50%. More interestingly, a total eradication of gray mold was obtained on tomato fruits infected by Botrytis cinerea and treated by M3-7, compared to those treated by BLB371. From the practical point of view, combining random mutagenesis and medium optimization could be considered as an excellent tool for obtaining promising biological products useful against phytopathogenic fungi.
authors.affiliation: Laboratory of Biopesticides (LBPES), Center of Biotechnology of Sfax, Sfax University, P.O. Box 1177, 3018 Sfax, Tunisie.
authors.forename: Fatma
authors.initials: F
authors.lastname: Masmoudi
authors.affiliation: Laboratory of Biopesticides (LBPES), Center of Biotechnology of Sfax, Sfax University, P.O. Box 1177, 3018 Sfax, Tunisie.
authors.forename: Saoussen
authors.initials: S
authors.lastname: Ben Khedher
authors.affiliation: Laboratoire de Chimie Industrielle II,ENIS route de Soukra, Sfax University, P.O. Box 3038, Sfax, Tunisie.
authors.forename: Amel
authors.initials: A
authors.lastname: Kamoun
authors.affiliation: Department of Biological and Environmental Sciences, College of Arts and Sciences, Qatar University, P.O. Box 2713, Doha, Qatar.
authors.forename: Nabil
authors.initials: N
authors.lastname: Zouari
authors.affiliation: Laboratory of Biopesticides (LBPES), Center of Biotechnology of Sfax, Sfax University, P.O. Box 1177, 3018 Sfax, Tunisie.
authors.forename: Slim
authors.initials: S
authors.lastname: Tounsi
authors.affiliation: Laboratory of Biopesticides (LBPES), Center of Biotechnology of Sfax, Sfax University, P.O. Box 1177, 3018 Sfax, Tunisie. Electronic address: mohamed.trigui@ipeis.rnu.tn.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Trigui
mesh_terms: D000069977:Bacillus amyloliquefaciens / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D018533:Biomass; D001709:Biotechnology / Q000379:methods; D020171:Botrytis / Q000472:pathogenicity / Q000502:physiology*; D003470:Culture Media; D018551:Solanum lycopersicum / Q000382:microbiology; D016296:Mutagenesis; D010572:Pest Control, Biological / Q000379:methods; D010935:Plant Diseases / Q000382:microbiology / Q000517:prevention & control*; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D003470:Culture Media; D012336:RNA, Ribosomal, 16S
keywords: Antifungal metabolites; Bacillus amyloliquefaciens; Biological control; Hybrid design; Medium optimization; Mutagenesis