Bacterial Spot Disease Management in Solanaceous Crops

Bacterial spot, caused by several Xanthomonas species, is a major constraint on pepper, tomato and related solanaceous crops under warm, humid conditions worldwide. In the absence of fully effective chemical controls, integrated disease management combines cultural practices—such as sanitation, crop rotation and careful irrigation—with genetic resistance and novel antimicrobials. Host resistance ranges from race‐specific resistance genes to non‐race‐specific loci that confer broad‐spectrum tolerance. However, rapid pathogen evolution, including the erosion of type III effector repertoires and the emergence of copper‐tolerant strains, has limited the durability of single‐gene resistance and copper‐based bactericides. Recent advances in molecular diagnostics enable early detection and pathogen surveillance, while genomics reveals the mechanisms by which insertion sequences and transposons drive virulence variability. Emerging biorational approaches include nanomaterials, biological antagonists and optimised formulations of micronutrients. Looking ahead, the deployment of gene pyramiding, improved forecasting models and targeted antimicrobial delivery promises to reduce disease pressure, enhance yield stability and lessen reliance on traditional copper sprays.

Research from Nature Portfolio

Recent studies have demonstrated the potential of hybrid copper–zinc nanoparticles to control copper‐tolerant Xanthomonas strains without phytotoxic effects. These multi‐site nanoparticles disrupt bacterial growth in vitro, significantly reduce disease severity on tomato transplants and impair the production of xanthomonadin pigment—a key component of pathogen survival and virulence—thus offering a promising alternative to conventional copper sprays.

Bacterial Spot Disease Management in Solanaceous Crops publication trend

The graph below shows the total number of articles in bacterial spot disease management in solanaceous crops across all publications each year (not limited to Nature Index journals).

Technical terms

Xanthomonas: A genus of Gram‐negative bacteria that includes multiple species causing bacterial spot in tomato and pepper.

Type III effector: A protein secreted by pathogenic bacteria via the type III secretion system to modulate host immunity and facilitate infection.

Non‐race‐specific resistance: Broad‐spectrum resistance conferred by plant genes effective against multiple pathogen strains, not limited to particular races.

Copper tolerance: The ability of bacterial strains to survive or proliferate in the presence of copper‐based bactericides.

Nanoparticle: An engineered particle between 1 and 100 nanometres in size, used here to deliver antimicrobial metals with enhanced efficacy.

References

1. Mapping of the bs5 and bs6 non-race-specific recessive resistances against bacterial spot of pepper. Frontiers in Plant Science (2023).
2. Investigating the impact of insertion sequences and transposons in the genomes of the most significant phytopathogenic bacteria. Microbial Genomics (2024).
3. Whole-Genome Sequences of Xanthomonas euvesicatoria Strains Clarify Taxonomy and Reveal a Stepwise Erosion of Type 3 Effectors. Frontiers in Plant Science (2016).
4. Bactericidal Activity of Copper-Zinc Hybrid Nanoparticles on Copper-Tolerant Xanthomonas perforans. Scientific Reports (2019).
5. Screening Wild Pepper Germplasm for Resistance to Xanthomonas hortorum pv. gardneri. Sustainability (2023).
6. Potential of Novel Magnesium Nanomaterials to Manage Bacterial Spot Disease of Tomato in Greenhouse and Field Conditions. Plants (2023).