Isolation of lipopeptide antibiotics from Bacillus siamensis: a potential biocontrol agent for Fusarium graminearum.

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From: Canadian Journal of Microbiology(Vol. 68, Issue 6)
Publisher: NRC Research Press
Document Type: Report
Length: 5,569 words
Lexile Measure: 1490L

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Abstract :

Fusarium head blight (FHB), a destructive fungal disease that can cause damage to various crops and reduce yield and quality, is primarily caused by several species of the soil-borne fungal genus Fusarium, which produce mycotoxins that contaminate grains and may cause various severe chronic diseases in humans and livestock. In recent years, Bacillus spp. have been reported to be good producers of antifungal antibiotics against FHB. This study aimed to explore the potential role of a newly identified Bacillus strain, designated as CU-XJ-9, against FHB. This strain, which was isolated from traditional Chinese fermented food, was identified as Bacillus siamensis and confirmed to produce lipopeptide biosurfactants, which according to the analysis by quadrupole time-of-flight tandem mass spectrometry (Q-TOF-MS/MS) may belong to the iturin lipopeptide family. At 100 [micro]g/mL, the isolated antifungal compounds completely inhibited conidial germination. Observation of the effects of the isolated antifungal compounds on the mycelia of F. graminearum by scanning electron microscopy revealed obvious nodes in the middle of the mycelia and destroyed mycelial structures, and these changes became more pronounced with increasing dose. Overall, this study provides important information regarding the ability of Bacillus siamensis to produce lipopeptide biosurfactants, which showed significant antagonistic activity against F. graminearum. Key words: Q-TOF-MS/MS, Fusarium graminearum, Bacillus siamensis, lipopeptides biosurfactants. La fusariose de l'epi, une maladie fongique destructrice qui peut endommager diverses cultures et en reduire le rendement et la qualite, est principalement causee par plusieurs especes du genre Fusarium presentes dans le sol, qui produisent des mycotoxines qui contaminent le grain et peuvent causer diverses maladies chroniques graves chez les humains et le betail. Ces dernieres annees, Bacillus spp. ont ete signales comme de bons producteurs d'antibiotiques antifongiques contre la fusariose de l'epi. Cette etude visait a explorer le role potentiel d'une souche de Bacillus recemment identifiee, designee sous le nom de CU-XJ-9, contre la fusariose. Cette souche, isolee a partir d'un aliment fermente traditionnel chinois, a ete identifiee comme etant Bacillus siamensis et il s'avere qu'elle produit des biosurfactants lipopeptidiques, qui, selon l'analyse par spectrometrie de masse en tandem quadripole-temps de vol (Q-TOF-MS/ MS), pourraient appartenir a la famille des iturines, des lipopeptides. Les composes antifongiques isoles inhibaient completement la germination des conidies a 100 [micro]g/mL. L'observation par microscopie electronique a balayage des effets des composes antifongiques isoles sur les myceliums de F. graminearum a revele des noeuds evidents au milieu des myceliums et des structures myceliennes detruites, et ces changements devenaient plus prononces avec l'augmentation de la dose. Dans l'ensemble, cette etude fournit des informations importantes sur la capacite de Bacillus siamensis a produire des biosurfactants lipopeptidiques qui ont montre une activite antagoniste significative contre F. graminearum. [Traduit par la Redaction] Mots-cles: Q-TOF-MS/MS, Fusarium graminearum, Bacillus siamensis, biosurfactants lipopeptidiques.

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Gale Document Number: GALE|A706322308