Potentiality of Bacillus subtilis as biocontrol agent for management of anthracnose disease of chilli caused by Colletotrichum gloeosporioides OGC1

Abstract

A soil bacterium, Bacillus subtilis, isolated from the rhizosphere of Chilli, showed high antagonistic activity against Colletotrichum gloeosporioides OGC1. A clear inhibition zone of 0.5–1 cm was observed in dual plate assay. Microscopic observations showed a clear hyphal lysis and degradation of fungal cell wall. In dual liquid cultures, the B. subtilis strain inhibited the C. gloeosporioides up to 100 % in terms of dry weight. This strain also produced a clear halo region on chitin agar medium plates containing 0.5 % colloidal chitin, indicating that it excretes chitinase. The strain also produced other mycolytic enzymes—glucanase and cellulase, demonstrated by a clear zone of hydrolysis of yeast cell wall glucan (YCW 0.1 % v/v) and carboxymethylcellulose (CMC 0.1 % v/v). In liquid cultures, the strain showed appreciable levels of chitinase, glucanase and cellulase activities and hydrolytic activity with C. gloeosporioides OGC1 mycelia as the substrate. The role of the B. subtilis strain in suppressing the fungal growth in vitro was studied in comparison with a UV mutant of that strain, which lacked both antagonistic and hydrolytic activity. The mycolytic enzyme mediated antagonism of B. subtilis was further demonstrated by heat inactivation (70–100 °C), treatment with trypsin and TCA of the crude enzyme extract which lacked antifungal property also. Treatment of the chilli seeds with Bacillus sp. culture showed 100 % germination index similar to the untreated seeds. The treatment of the seed with co-inoculation of the pathogen with Bacillus sp. culture showed 65 % reduction in disease incidence by the treatment as compared to the seed treated with pathogen alone (77.5 %).

Genetic, physiological and biochemical characterization of Bacillus sp . strain RMB7 exhibiting plant growth promoting and broad spectrum antifungal activities

“…But the inoculation of B. subtilis RMB7 alone resulted in 400-600 folds increase in plant biomass and >85% disease suppression in Arugula plants showing extensively high potential for disease control as well as plant growth promotion. Disease control activity of RMB7 (cells only) may be attributed to the higher production of antifungal metabolites and the collective action of various factors i.e., chitinase, cellulase, siderophores that have a profound role in disease suppression along with cyclic lipopeptides [42,43]. Although, B. Subtilis antagonistic activity have been reported on different plants but this study is the first report showing higher level of in vivo antagonistic activity of B. Subtilis against P. irregulare on Arugula plants.…”

Synchrotron-based FTIR microspectroscopy of chili resistance induced by Bacillus subtilis strain D604 against anthracnose disease

“…SPT41.1.3 effectively reduced the severity of anthracnose on seeds by 41.90% when compared to controls under field conditions. A cell suspension of B. licheniformis BFP011 also reduced the disease severity of C. capsici by more than 30% (Plodpai et al 2008;Ashwini & Srividya 2014).…”

“…Resistance inducers have been extensively evaluated as a means to control plant diseases based on the induced resistance (IR) concept including ISR and systemic acquired resistance Buensanteai et al 2009;Ashwini & Srividya 2014). IR is part of the plant innate defense system that confers long-lasting protection against a broad range of pathogens Conrath et al 2006).…”

Biocontrol of Fusarium spp., Causal Agents of Damping-off in Cotton Plants by Native Bacillus subtilis Isolated from Prosopis juliflora

“…On the other hand, the obtained result showed that in both assays (dual-culture and cell free supernatant), strain ALICA significantly inhibited the growth of pathogenic fungi such as: F. solani, F. equiseti, and F. oxysporum in comparison with control. Similarly, Ashwini and Srividya (2014) found that B. subtilis inhibited fungal growth of Alternaria (3) spp. (55%), Colletotrichum gloeosporioides (57%), Phytophthora capsici (55%), Rhizoctonia solani (42%), F. solani (42%), F. oxysporum (40%) and Verticillium sp.…”