Lisianthus Fusaria wilt: inter- and intra-specific variation in virulence of pathogens and biocontrol of the disease based on vietnamese Streptomyces goshikiensis STR61.

Abstract

Aims: The study aimed to compare the pathogenicity of Vietnamese Fusaria species causing lisianthus Fusaria wilt (LFW) and to isolate, identify, and evaluate the potential of native Streptomyces for disease control.

Methods and results: Pathogenicity assays on 11 Vietnamese isolates of Fusarium vanleeuwenii, Neocosmospora solani, and F. annulatum revealed significant inter- and intra-specific variations in virulence. Fusarium vanleeuwenii was the most aggressive, followed by N. solani, while F. annulatum was the least pathogenic. Screening of rhizosphere soil led to the identification of S. goshikiensis STR61, which exhibited strong antifungal activity against the growth of F. oxysporum, F. fujikuroi, and F. incarnatum-equiseti species complexes by over 69%, but showed lower efficacy (43.4%) against F. solani species complex. In pot assay against F. vanleeuwenii-inducing LFW, STR61 significantly reduced disease incidence (76.3%) and severity (80.6%), while promoting plant growth.

Conclusions: The outcome of LFW was driven by species and isolates, with F. vanleeuwenii being most aggressive. Streptomyces goshikiensis STR61 can be applied as a biocontrol agent against Fusaria diseases.