Fusarium oxysporum species complex (FOSC) can cause vascular wilt on over 100 cultivated plant species (Ma et al., 2013; Michielse & Rep, 2009; Pietro et al., 2003). Because of its significance, F. oxysporum is listed among the top 10 fungal pathogens by the journal “Molecular Plant Pathology” (Dean et al., 2012). In the New England region, wilt diseases caused by Fusarium oxysporum are common agricultural problems that affect the production of vegetables, including asparagus, tomatoes, eggplant production, ornamentals, and variety of flowers (Elmer & Marra, 2011;https://www.prevalentfungi.org/). The widespread resistance to existing fungicides and the persistence of the thick-walled fungal chlamydospores in the soil heightens the difficulty in controlling the diseases and emphasizes the importance of appropriate control measures.
The FOSC also contains endophytic strains that promote plant growth and/or protect plants against diseases (Brader et al., 2017). For instance, the endophytic strain Fo47, originally isolated from disease-suppressing soils (Alabouvette, 1986), has been used as a biocontrol agent to prevent disease from soil-borne pathogens by inducing the production of plant secondary metabolites and priming host resistance (Aime et al., 2013; Alabouvette et al., 2009; Benhamou et al., 2002; Benhamou & Garand, 2001; Olivain et al., 2006; Olivain & Alabouvette, 1999; Veloso & Díaz, 2012). Using endophytes as a biocontrol remains one of the most practical and cost-efficient strategies for managing plant diseases. However, the practice was hampered by our limited understanding of the molecular mechanisms involved in host-pathogen interactions.
The Ma lab has established a Fusarium oxysporum–Arabidopsis thaliana comparative model system that includes an endophyte, F. oxysporum strain Fo47, and a pathogen, F. oxysporum strain Fo5176 (Guo et al., 2021a; Martínez-Soto et al., 2023) (Figure 1A). The survival assay illustrated that Arabidopsis plants inoculated with Fo5176 were completely dead by 3 weeks, while Arabidopsis plants inoculated with Fo47 remained 100% healthy (Figure 1B) and reached a significantly (p < 0.001) greater shoot dry biomass, compared to plants mock-inoculated with water (Figure 1C).
This Hatch project takes advantage of this established system with a goal to dissect how plants differentiate friends (endophytes) versus foes (pathogens), focusing on fungal small secreted proteins. This study will not only advance scientific knowledge but also provide potential avenues for the management of vascular wilt diseases using the means of a fungal biocontrol.
