Antifungal activity of bioactive compounds produced by the endophyte Bacillus velezensis NC318 against the soil borne pathogen Sclerotium rolfsii Sacc
Ilham Barakat 1, C,E-F
Taha El Kamli 3, B,E-F
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Plant Protection unit, Hassan II Agronomic and Veterinary Institute, Morocco
Plant protection unit, National Institute of Agronomic Research, Morocco
Anti-doping control laboratory, Hassan II Agronomic and Veterinary Institute, Morocco
A - Research concept and design; B - Collection and/or assembly of data; C - Data analysis and interpretation; D - Writing the article; E - Critical revision of the article; F - Final approval of article
Michelle Gaëlle Siméone Bidima   

Plant Protection unit, Hassan II Agronomic and Veterinary Institute, Madinat al irfane BP 6202, 10000, Rabat, Morocco
Submission date: 2022-06-09
Acceptance date: 2022-09-02
Online publication date: 2022-09-13
  • Bacillus velezensis NC318 produced potent antifungal compounds against the plant pathogenic fungus Sclerotium rolfsii Sacc.
  • The secreted antifungal compounds could inhibit mycelial growth and sclerotia germination of the pathogen.
  • Lipopeptides, polyketides, and siderophores are involved in the control of the pathogen.
  • B. velezensis NC318 could be a promising biological control agent.
In a previous study, the endophytic Bacillus velezensis NC318 was isolated from the rhizosphere of date palm and showed strong antifungal activity against the soil-borne plant pathogenic fungus, Sclerotium rolfsii Sacc, the causal agent of Southern blight. The potential of the Bacillus genus in the inhibition of plant pathogens is mainly due to the production of certain bioactive compounds. In the present study, secondary metabolites extracted from the cell-free supernatant of strain NC318 showed strong antifungal activity on the mycelial growth and germination of S. rolfsii sclerotia in vitro. With 50 µL of bioactive compounds crude extracts, the mycelial growth inhibition rate was 97 % and any germination of sclerotia was reported. Chemical analysis of the secondary metabolite crude extracts performed by high performance liquid chromatography coupled with mass spectrometry (HPLC/MS), revealed that the secreted bioactive compounds belonged to the family of lipopeptides (iturin, fengycin, surfactin), polyketides (bacillaene, macrolactin, difficidin and bacilysin) and siderophores (bacillibactin). These results provide a better understanding of the biocontrol mechanism of the bacteria strain B. velezensis NC318 against the soil fungal pathogens, especially S. rolfsii root rot.
The authors have declared that no conflict of interests exist.