Biocontrol potential of Bacillus subtilis RH5 against sheath blight of rice caused by Rhizoctonia solani

Abstract

The sheath blight disease of rice caused by Rhizoctonia solani is widely prevalent and one of the most destructive diseases, affecting rice cultivation and loss worldwide. In the present study, a set of twenty Bacillus isolates from saline soil of Uttar Pradesh were tested for their biocontrol activity against R. solani with the aim to obtain a potential strain for the control of sheath blight disease toward ecofriendly and sustainable agriculture. The results of dual‐culture assay and scanning electron microscopic studies showed that the strain RH5 exhibited significant antagonistic activity (84.41%) against the fungal pathogen R. solani. On the basis of 16S rDNA sequencing analysis, the potential biocontrol strain RH5 was identified as Bacillus subtilis. Furthermore, the strain RH5 was characterized by different plant growth‐promoting (PGP) activities and induction of defense‐related enzymes in rice plants against R. solani. The strain RH5 posses various PGP attributes (indole acetic acid, siderophore, hydrogen cyanide production and phosphate, Zn, K solubility), hydrolytic enzymatic (chitinase, protease, cellulase, xylanase) activity, and presence of antimicrobial peptide biosynthetic genes (bacylisin, surfactin, and fengycin), which support the strain for efficient colonization of hyphae and its inhibition. Finally, the results of the greenhouse study confirmed that strain RH5 significantly increased plant growth and triggered resistance in rice plants through the production of defense‐related antioxidant enzymes.

The inhibitory effect of volatile organic compounds produced by Bacillus subtilis CL2 on pathogenic fungi of wolfberry

“…Past studies on the antifungal activity of Bacillus revealed that Bacillus can produce defense-related antioxidant enzymes [9], N-butyl-tetrahydro-5-oxofuran-2-carboxamide [10], lipopeptide, protein [11], and other such antifungal substances. Interestingly, the content and type of volatile organic compounds (VOCs) possessing antifungal activities released by different Bacillus species during the growth process are extremely different [12][13][14].…”

Genomic and physiological characterization of new Plant Growth Promoting Bacilli isolated from salt-pans

“…The biocontrol potential and the ability to enhance plant growth of PGPB are mostly attributed to their bioactive secondary metabolites. Proteins and metabolites released in the soil by PGPB, indeed, are implicated in root colonization, as well as in interactions with the plant immune response and the surrounding niche (Lugtenberg and Kamilova, 2009;Pieterse et al, 2014;Jamali et al, 2020). The strong antimicrobial activity of selected Bacillus strains is most likely due in part to the production of hydrolytic enzymes and siderophores observed in vitro assays and confirmed by genome analysis (Table 2 and 5).…”

The Role of Secretion Systems, Effectors, and Secondary Metabolites of Beneficial Rhizobacteria in Interactions With Plants and Microbes

“…Other secretion systems and efflux pumps release proteins and secondary metabolites into the medium, respectively. The secreted proteins and metabolites play roles in root colonization, as well as in interactions with the plant immune response and the surrounding prokaryotic and eukaryotic organisms (Figure 1; Lugtenberg and Kamilova, 2009;Pieterse et al, 2014;Wu et al, 2018;Jamali et al, 2020).…”

“…Other secretion systems and efflux pumps release proteins and secondary metabolites into the medium, respectively. The secreted proteins and metabolites play roles in root colonization, as well as in interactions with the plant immune response and the surrounding prokaryotic and eukaryotic organisms ( Figure 1 ; Lugtenberg and Kamilova, 2009 ; Pieterse et al, 2014 ; Wu et al, 2018 ; Jamali et al, 2020 ). The goal of this minireview is to describe important bacterial secreted effectors, secondary metabolites and secretion systems which play a role in the interactions of beneficial microbes with plants and surrounding microbes, including bacteria and fungi.…”