In Vitro Antifungal Activity of Burkholderia gladioli pv. agaricicola against Some Phytopathogenic Fungi

Abstract

The trend to search novel microbial natural biocides has recently been increasing in order to avoid the environmental pollution from use of synthetic pesticides. Among these novel natural biocides are the bioactive secondary metabolites of Burkholderia gladioli pv. agaricicola (Bga). The aim of this study is to determine antifungal activity of Bga strains against some phytopathogenic fungi. The fungicidal tests were carried out using cultures and cell-free culture filtrates against Botrytis cinerea, Aspergillus flavus, Aspergillus niger, Penicillium digitatum, Penicillium expansum, Sclerotinia sclerotiorum and Phytophthora cactorum. Results demonstrated that all tested strains exert antifungal activity against all studied fungi by producing diffusible metabolites which are correlated with their ability to produce extracellular hydrolytic enzymes. All strains significantly reduced the growth of studied fungi and the bacterial cells were more bioactive than bacterial filtrates. All tested Bulkholderia strains produced volatile organic compounds (VOCs), which inhibited the fungal growth and reduced the growth rate of Fusarium oxysporum and Rhizoctonia solani. GC/MS analysis of VOCs emitted by strain Bga 11096 indicated the presence of a compound that was identified as 1-methyl-4-(1-methylethenyl)-cyclohexene, a liquid hydrocarbon classified as cyclic terpene. This compound could be responsible for the antifungal activity, which is also in agreement with the work of other authors.

Potential of some bacteria for biological control of postharvest citrus green mould caused by Penicillium digitatum

“…The degradation of fungal cell walls with the production of hydrolytic enzymes of bacterial isolates is one of the most important mechanisms for bio-control of phytopathogenic fungi (Weller 2007;Elshafie et al 2012). These enzymes such as chitinase (Ordentlich et al 1988), protease (Saligkarias et al 2002), and glucanase (Leelasuphakul et al 2006).…”

Bio-suppression of Sclerotinia Stem Rot of Tomato and Biostimulation of Plant Growth Using Tomato-associated Rhizobacteria

“…Similar effects are reported on tomato seeds using Burkholderia gladioli pv. agaricicola [58] and Bacillus spp. rhizobacterial strains [59].…”

Inhibitory Activity of <i>Burkholderia</i> sp. Isolated from Soil in Gotsu City, Shimane, against <i>Magnaporthe oryzae</i>

“…The inhibitory activity of microorganisms is exerted either directly through antagonism to pathogen development, or indirectly by eliciting a plant-mediated resistance response. Mechanisms responsible for inhibitory activity include inhibition of pathogen growth, competition for colonization sites, nutrients, and minerals, parasitism, and mycophagy [4]. It is well known that microorganisms have different physiological characteristics and produce different compounds even among members in the same species.…”