Efficacy of Bacillus subtilis V26 as a biological control agent against Rhizoctonia solani on potato

Abstract

The aim of this study is to evaluate the efficacy of the strain Bacillus subtilis V26, a local isolate from the Tunisian soil, to control potato black scurf caused by Rhizoctonia solani. The in vitro antifungal activity of V26 significantly inhibited R. solani growth compared to the untreated control. Microscopic observations revealed that V26 caused considerable morphological deformations of the fungal hyphae such as vacuolation, protoplast leakage and mycelia crack. The most effective control was achieved when strain V26 was applied 24h prior to inoculation (protective activity) in potato slices. The antagonistic bacterium V26 induced significant suppression of root canker and black scurf tuber colonization compared to untreated controls with a decrease in incidence disease of 63% and 81%, respectively, and promoted plant growth under greenhouse conditions on potato plants. Therefore, B. subtilis V26 has a great potential to be commercialized as a biocontrol agent against R. solani on potato crops.

Bacillus: A Biological Tool for Crop Improvement through Bio-Molecular Changes in Adverse Environments

“…Bacillus spp. attach to the mycelial cell walls, and the chitosanase (EC 3.2.1.123), protease (EC 3.4.21.112), cellulase (EC 3.2.1.4), glucanase (EC 3.2.1.21), siderophores, and HCN of the bacteria crack and deform the hyphae, which leads to altered cell structure and functions due to vacuolation and protoplast leakage (Ben-Khedher et al, 2015b ; Han et al, 2015 ; Narendra-Babu et al, 2015 ). Bacterially synthesized antifungal peptides, such as iturin, fengycin, mixirin, pumilacidin, surfactin, and a novel cyclic peptide with a molecular weight of 852.4 Da, are involved in the destruction of the pathogenic fungi in rhizospheres (Han et al, 2015 ; Yamamoto et al, 2015 ; Figure 1 ).…”

Stepwise-Selected Bacillus amyloliquefaciens and B. subtilis Strains from Composted Aromatic Plant Waste Able to Control Soil-Borne Diseases

“…In the last few decades, the use of eco-friendly control means of soil-borne pathogens has become a popular alternative to conventional chemical treatments in a lot of cropping systems [37]. In fact, several studies and reviews highlighted the possibility to isolate new potential BCAs and use them to reduce crop losses [12,[38][39][40][41]. In this study, we carried out a step-by-step selection for the S. minor and R. solani controllability of spore-forming bacterial isolates, obtained from aromatic plant residue-based composts.…”

Swine manure on the control of damping-off in beetroot seedlings

“…The increased microbial activity promoted antagonism among the microorganisms present in the soil, which is another factor responsible for reducing the damping-off caused by R. solani in the beetroot seedlings of the present study ( Figures 1B and 2B). Antagonistic effect on this pathogen is reported for numerous microorganisms such as actinomycetes (3), Pseudomonas flurences (21), Bacillus subtilis (12) and Trichoderma sp. (14).…”