Additive effect of the Streptomyces albus XJC2‐1 and dimethomorph control pepper blight (Capsicum annuum L.)

Abstract

BackgroundPepper blight, caused by Phytophthora capsici, is a destructive soilborne disease, which poses a serious threat to pepper, Capsicum annuum L., production. Chemical fungicides, which mainly are used to control pepper blight, have a negative effect on the environment, rendering biological control as a promising alternative to maintain the balance between ecology and pest management. The purpose of this study was to screen the biocontrol bacteria, reduce the dosage of fungicides and increase the stability of biocontrol bacteria, and to find the mixing ratio of biocontrol bacteria and fungicides giving the best control effect.ResultsWe isolated actinomycetes strains from the soil surrounding the roots of healthy pepper plants amongst field‐grown plants infected with P. capsici. Of these, Streptomyces albus XJC2‐1 showed a strong inhibition effect on the growth of P. capsici, with an inhibition rate of ≤85%. XJC2‐1 effectively inhibited the formation of sporangium and release of zoospores of P. capsici as well as directly destroyed its hyphae, to achieve the inhibitory effect. Transcriptomic profiling of pepper leaves, postirrigation of plants with the XJC2‐1 fermentation broth, revealed upregulation of genes related to the photosynthesis pathway in pepper. Furthermore, XJC2‐1 treatment improved the net photosynthetic rate and intercellular CO2 concentration, thereby improving the pepper plant's resistance to pathogens. The combination of XJC2‐1 with the fungicide dimethomorph (8 μg mL−1) displayed strong synergism in inhibition of P. capsici infection, with a control efficiency as high as 75.16%, thus providing a basis for its application in the field.ConclusionOur study demonstrated that S. albus XJC2‐1 inhibited Phytophthora pathogens from infecting pepper plants and enhanced plant host resistance. The combination of XJC2‐1 and dimethomorph displayed a more stable and stronger control effect on pepper blight, showing potential for the future application of XJC2‐1 in the field of biological control. © 2023 Society of Chemical Industry.

Inhibition of Monilinia fructicola sporulation and pathogenicity through eucalyptol‐mediated targeting of MfCat2 by Streptomyces lincolnensis strain JCP1‐7

“…Actinomycetes constitute a diverse group of gram-positive bacteria distinguished by their branched mycelium, from which their name, derived from the radial edges of their colonies, is derived (Long et al, 2023). Notably, the mol % content of G+C in their cells tends to be relatively high, typically exceeding 55% (Proft & Baker, 2008).…”

“…Within this group, the genus Streptomyces and its related taxa represent the earliest studied and applied biocontrol actinomycetes in various production processes (Nazari et al, 2023). Two primary methods are employed for their application: direct utilization of actinomycetes and the utilization of metabolites produced by these actinomycetes (Long et al, 2023). In this context, the utilization of the fermentation products of actinomycetes is the predominant approach.…”