Endophyte-based biocontrol discovery from fusarium-resistant tomato genotypes

Overview

This research initiative targets the discovery of bacterial endophytes that contribute to natural resistance against Fusarium oxysporum, the causal agent of Fusarium wilt in tomato. The project investigates whether tomato genotypes resistant to this pathogen harbor a distinct endophyte community with enhanced biocontrol attributes compared to susceptible varieties. By isolating and characterizing these beneficial microorganisms, the work aims to develop biologically based disease management solutions that reduce reliance on chemical fungicides and support sustainable agriculture.

The platform is anchored in growing evidence that plant genotype, soil microbial diversity, and agricultural practices shape the assembly of endosphere and rhizosphere microbiomes. Prior studies on bacterial wilt caused by Ralstonia solanacearum demonstrated that resistant tomato plants host higher endophyte diversity and a greater proportion of antagonistic isolates. This project applies a similar framework to Fusarium wilt, leveraging previously identified resistant and susceptible wild tomato accessions to systematically compare endophyte communities and their biocontrol potential.

Technical specifications

Research approach:

• Comparative isolation of bacterial endophytes from roots and stems of resistant versus susceptible wild and commercial tomato accessions
• Cultivation under controlled conditions using at least two different culture media to maximize recoverable diversity
• Inoculation of plants with Fusarium oxysporum in substrates with varying microbial diversity to assess community assembly
• Characterization of promising isolates through standardized antagonistic assays against Fusarium oxysporum
• Screening for production of biocontrol-relevant metabolites including siderophores, hydrogen cyanide, proteases, and indole acetic acid
• Molecular identification of candidate biocontrol strains via ribosomal gene sequencing
• Statistical comparison of culturable endophyte community structure and antagonistic potential between resistant and susceptible genotypes

Key capabilities:

• Access to characterized resistant and susceptible wild tomato accessions of S. pimpinellifolium and L. sculetum var. cerasiforme
• Established protocols for endophyte isolation under pathogen challenge conditions
• Multi-assay screening pipeline combining in vitro antagonism with metabolite profiling

Technology readiness level

The project is at an early discovery stage. Preliminary work has yielded sixteen bacterial endophyte isolates from a susceptible commercial cultivar challenged with Fusarium oxysporum, with a small subset demonstrating in vitro growth inhibition of the pathogen. However, the production of specific biocontrol compounds by these isolates has not yet been determined, and resistant cultivars were not included in the initial comparison. The next phase will systematically expand isolation efforts to include resistant genotypes, enabling the first direct comparison of endophyte-mediated biocontrol potential between susceptible and resistant tomato plants. Output from this research will be candidate bacterial strains with documented antagonistic activity and初步 characterization suitable for further greenhouse and field validation.