The symbiosis of Bacillus subtilis L-forms with Chinese cabbage seedlings inhibits conidial germination of Botrytis cinerea

Abstract

Aims: To establish whether germination of Botrytis cinerea was affected by the symbiosis of Bacillus subtilis L-form bacteria with Chinese cabbage. Methods and Results: Germinating seeds of Chinese cabbage were co-cultivated with either L-forms of Bacillus subtilis or 5% (w/v) mannitol by soaking for 3 h. Seeds were then washed in sterile water, sown on a minimal medium and incubated in controlled conditions. L-form symbiosis was detected over a time course by ELISA. Conidial germination of Botrytis cinerea was signi®cantly reduced on cotyledonous leaves of L-form-treated plants compared with controls. Conclusions: Symbiosis of B. subtilis L-form bacteria during seed germination of Chinese cabbage inhibits conidial germination in plants on subsequent exposure to Botrytis cinerea. Signi®cance and Impact of the Study: This is the ®rst account of plant symbiosis with L-form bacteria showing antagonism to a fungal plant pathogen. This has promising implications for the use of this L-form as a biocontrol agent.

Morphogenesis of Streptomyces in Submerged Cultures

“…While protoplasts cannot propagate, streptomycetes can also form so-called L-forms (Innes & Allan, 2001). Biocontrol activity was shown for Pseudomonas and Bacillus species (Amijee et al, 1992;Walker, Ferguson, Booth, & Allan, 2002;Waterhouse, Buhariwalla, Bourn, Rattray, & Glover, 1996), but could also be true for streptomycetes, which naturally produce a large arsenal of antifungal and antimicrobial compounds (Hopwood, 2007). Subsequent cultivations in osmotically balanced media can lead to the acquisition of mutations that allow these cells to propagate without their cell wall, even in the absence of the inducing agents (i.e., penicillin and lysozyme; Innes & Allan, 2001;Leaver, Dominguez-Cuevas, Coxhead, Daniel, & Errington, 2009;Mercier, Kawai, & Errington, 2013;Errington, 2013).…”

Killer toxin of Pichia membranifaciens and its possible use as a biocontrol agent against grey mould disease of grapevine

“…With rekindled public concern about environmental issues, together with the awareness that upsetting the natural microbial balance can lead to severe outbreaks of disease, plant pathologists are increasingly interested in the possibilities of biological control. Biocontrol, a non-hazardous alternative to the use of chemical fungicides, involves the use of biological processes to reduce crop loss and various micro-organisms (Bacillus circulans, Bacillus subtilis, Candida oleophila, Candida sake, Debaryomyces hansenii, Gliocladium, Trichoderma, Pichia guillermondii, Pythium spp., etc) have been reported to protect plants from fungal infections (Barka et al, 2000;Droby et al, 1996;Masih et al, 2000;Masih & Paul, 2002;Walker et al, 1995Walker et al, , 2002Wilson et al, 1996).…”

“…With rekindled public concern about environmental issues, together with the awareness that upsetting the natural microbial balance can lead to severe outbreaks of disease, plant pathologists are increasingly interested in the possibilities of biological control. Biocontrol, a non-hazardous alternative to the use of chemical fungicides, involves the use of biological processes to reduce crop loss and various micro-organisms (Bacillus circulans, Bacillus subtilis, Candida oleophila, Candida sake, Debaryomyces hansenii, Gliocladium, Trichoderma, Pichia guillermondii, Pythium spp., etc) have been reported to protect plants from fungal infections (Barka et al, 2000;Droby et al, 1996;Masih et al, 2000;Masih & Paul, 2002;Walker et al, 1995Walker et al, , 2002Wilson et al, 1996).Since it was first reported (Makower & Bevan, 1963), the killer phenomenon in yeasts has been extensively studied in several genera and species, and its importance is gaining further recognition by industrialists, clinical microbiologists and molecular biologists (Fink & Styles, 1972; Provost et al, 1995; Séguy et al, 1996;Tipper & Bostian, 1984;Vondrejs et al, 1996). The food and beverage industries were among the first to explore the ability of toxin-producing yeasts to kill other micro-organisms (Javadekar et al, 1995).…”

Isolation and characterization of a novel Bacillus strain from coffee phyllosphere showing antifungal activity

“…tritici , Rhizoctonia solani , Pythium irregulare , Pythium ultimum (Kim et al . 1997) and Botrytis cinerea (Walker et al . 1998, 2002).…”