The antimicrobial peptide AsR416 can inhibit the growth, sclerotium formation and virulence of Rhizoctonia solani AG1-IA

Abstract

Plant antimicrobial peptides (AMPs) as a part of plant defense responses, are small soluble defense molecules which can inhibit the growth of pathogens. This study evaluates the effect of an antimicrobial peptide obtained from Allium sativum (AsR416) on Rhizoctonia solani (AG1-IA) the causal agent of rice sheath blight, in vitro and in vivo conditions. Firstly, the obtained results revealed that AsR416 (100 mg ml−1) inhibited the growth and sclerotia production of R. solani AG1-IA. Furthermore, these results showed the mode of action and mechanisms of AsR416 effect in inhibiting sclerotia formation of R. solani AG1-IA via metabolomics tools. AsR416 decreased the biomass of R. solani AG1-IA in liquid culture. In addition, nitro blue tetrazolium and evans blue staining methods revealed that the antimicrobial peptide induced O2− formation in the hyphal cells and mycelia cell death of R. solani AG1-IA, respectively. AsR416 delayed the pathogen infection process and decreased the severity of rice sheath blight disease in vitro and in vivo conditions. AsR416 reduced activity of cellulase, which is one of the virulence factors of this pathogen. The number of sclerotia decreased on plants treated with AsR416 after 2 months compared with the control. Considering the need to reduce application of hazardous synthetic fungicides against pathogenic fungi, using AMPs could be a successful method to increase rice production and reduce the use of chemical fungicides against sheath blight disease.