Bacillus amyloliquefaciens Q‐426 as a potential biocontrol agent against Fusarium oxysporum f. sp. spinaciae

Abstract

In recent years, Bacillus species have received considerable attention for the biological control of many fungal diseases. In this study, Bacillus amyloliquefaciens Q-426 was tested for its potential use against a variety of plant pathogens. Our screen for genes involved in the biosynthesis of antifungal agents revealed that the fen and bmy gene clusters are present in the Q-426 genome. Lipopeptides such as bacillomycin D, fengycin A, and fengycin B were purified from the bacterial culture broth and subsequently identified by ESI-mass spectrometry. The minimal inhibitory concentration of fengycin A against Fusarium oxysporum f. sp. spinaciae W.C. Snyder & H.N. Hansen O-27 was determined to be 31.25 μg ml(-1) . However, exposure of fungal cells to 50 μg ml(-1) of fengycin A did not allow permeation of fluorescein diacetate into the cytoplasm through the cell membrane. Moreover, leakage of intracellular inorganic cations, nucleic acid and protein were also not detected, indicating that the fungal cell membrane is not the primary target of action for fengycin A. Profound morphological changes were observed in the F. oxysporum strain and spore germination was completely inhibited, suggesting that 50 μg ml(-1) of fengycin A acts, at least, as a fungistatic agent.

Inhibition of biofilm in Bacillus amyloliquefaciens Q-426 by diketopiperazines

“…amyloliquefaciens Q-426 had been isolated from compost samples in Dalian of China based on its antifungal activity. In previous study, B. amyloliquefaciens Q-426 was found to be a potential biocontrol agent against fungi and bacteria, but the biofilm formation played a negative role on it (Zhao et al 2013;Zhao et al 2014). In this study, the DKPs extracted from B. amyloliquefaciens Q-426, which was suspected as signal molecule of several bacterial (Degrassi et al 2002;Holden et al 1999;Wang et al 2010b), can inhibit the biofilm formation of the strain by inhibiting the extracellular polymeric matrix formation.…”

Purification and characterisation of a fungicidal peptide from Bacillus amyloliquefaciens NCPSJ7

“…For the antimicrobial substances secreted by B. amyloliquefaciens, most peptides were tested to be active against fungi. The most common class may be lipopeptides with small molecular mass, broadly including surfactin (~1.36 kDa), iturin (~1.1 kDa), and fengycin (~1.5 kDa), which have potent applications in food industry, therapeutics, plant protection, and insect control (Zhao et al 2014;Guo et al 2015;Meena & Kanwar 2015). Among the other fungicidal peptides from Bacillus amyloliquefaciens, a smaller peptide with the mass of 852.4 Da was purified and it showed activities against pathogenic fungi (Han et al 2015).…”

“…There are a lot of reports on the antifungal activities of B. amyloliquefaciens (Chen et al 2007;Arguelles Arias et al 2013;Li et al 2013;Zhang et al 2013;Zhao et al 2014;Han et al 2015;Nam et al 2015;Yamamoto et al 2015). It is known to produce various potent antimicrobial substances which provide an alternative approach to protect the food from pathogenic organisms (Sumi et al 2015).…”

Antifungal Screening of Bioprotective Isolates against Botrytis cinerea, Fusarium pallidoroseum and Fusarium moniliforme

“…B. megaterium, B. coagulans, B. thuringiensis BT2 and several B. amyloliquefaciens isolates demonstrated both strong biosurfactant activity and suppression of B. cinerea, F. pallidoroseum, and F. moniliforme, implying the ability to synthesize antifungal lipopeptides. The production of antifungal lipopeptides has been identified in other strains of the species of Bacillus used in this study, including B. amyloliquefaciens [11,12,24], B. coagulans [21], B. megaterium [23], and B. thuringiensis [15,16,57]. B. pumilus and O. sojae demonstrated weak biosurfactant activity but no fungal suppression.…”