Biocontrol potential of the endophytic Epicoccum nigrum HE20 against stripe rust of wheat

• Published in: Pesticide biochemistry and physiology 2023-08, Vol.194, p.105517-105517, Article 105517
• Main Authors: El-Sharkawy, Hany H.A., Rashad, Younes M., Elazab, Nahla T.
• Format: Article
• Language: English
• Subjects: Ascomycota; Basidiomycota - physiology; Defense; Endophyte; Plant Diseases - microbiology; Puccinia striiformis; Resistance; Triticum - microbiology; Ultrastructure
• ISSN: 0048-3575; 1095-9939
• DOI: 10.1016/j.pestbp.2023.105517

Biological control using endophytic microorganisms represents an eco-friendly and effective alternative to the health-hazardous chemical fungicides used to control devastating plant diseases such as stripe rust in wheat. In this study, the inhibitory potential of the endophytic Epicoccum nigrum HE20, isolated from a healthy wheat plant, was screened against uredospores germination in vitro. A high suppression (96%) in the germination of the uredospores was recorded. GC‐MS analysis of the culture filtrate of E. nigrum HE20 showed a production of various secondary metabolites with an antifungal background such as butyric acid, α-linolenic acid, hexanoic acid, lactic acid, 10,12-Tricosadiynoic acid, and pentadecanoic acid. Results from the greenhouse experiment revealed that the application of E. nigrum HE20 suspension led to a reduction in the disease severity by 87.5%, compared with the untreated-infected plants. Real-time PCR results exhibited an overexpression in three defensive genes (JERF3, GLU, and PR1) in the infected wheat plants, in response to the application of E. nigrum HE20, recorded 8-, 15.8-, and 3.5-fold, respectively. In addition, an increment in the phenolic content, activity of POD, PPO, and CAT, and a reduction in the lipid peroxidation were recorded due to the endophyte application. Transmission electron microscopic observations indicated mitigation of the pathogen in wheat cells after the treatment with E. nigrum HE20 metabolite. Furthermore, a growth-promoting effect was also observed due to E. nigrum HE20 application, as well as an increment in the total photosynthetic pigments in wheat leaves. Based on these results, it can be concluded that E. nigrum HE20 is a probable efficient bioagent against stripe rust in wheat. However, its field evaluation is highly necessary in the future studies. [Display omitted] •E. nigrum HE20 exhibited 96% suppression in germination of P. striiformis uredospores.•Application of E. nigrum HE20 led to 87.5% reduction in severity of strip rust of wheat.•Overexpressed defense-related genes in infected wheat plants.•Elicited activities of the antioxidant enzymes POD, PPO, and CAT.•Mitigated the ultrastructural effects in wheat cells due to the infection.