# Enhanced Tomato Yellow Leaf Curl Thailand Virus Suppression Through Multi-Disease and Insect-Resistant Tomato Lines Combining Virus and Vector Resistance

## TL;DR

Tomato plants with combined virus and whitefly resistance show better protection against tomato yellow leaf curl disease than those with only one type of resistance.

## Contribution

Demonstrates the effectiveness of combining virus and vector resistance genes in tomato lines for enhanced disease suppression.

## Key findings

- Multi-resistant tomato lines had higher acylsugar levels, deterring whiteflies and reducing virus accumulation.
- Lines with combined resistance showed milder disease symptoms and lower virus levels over time.
- Integrated resistance outperformed single-resistance lines and susceptible controls in pest and disease management.

## Abstract

Tomatoes (Solanum lycopersicum) are highly vulnerable to the whitefly-transmitted tomato yellow leaf curl disease (TYLCD). This study evaluates multi-disease and insect-resistant tomato lines incorporating Ty-1/Ty-3 genes (for virus resistance) and WF2-10 and WF3-09 genes (for whitefly resistance). Multi-disease and insect-resistant lines exhibit significantly higher acylsugar levels, which contribute to whitefly deterrence. These lines displayed reduced tomato yellow leaf curl Thailand virus (TYLCTHV) accumulation and milder disease symptoms over time. It was found that lines combining virus and vector resistance performed better than those with only Ty-resistance, whitefly resistance, or the susceptible control.

Tomato (Solanum lycopersicum) is an essential vegetable crop cultivated worldwide, but its production is highly vulnerable to tomato yellow leaf curl disease (TYLCD), which is transmitted by whiteflies (Bemisia tabaci). Management strategies typically focus on controlling either the virus or its vector. This study evaluates the effectiveness of multi-disease and insect-resistant tomato lines, developed by the World Vegetable Center (WorldVeg), which integrate Ty-1/Ty-3 genes for virus resistance and WF2-10 and WF3-09 genes for whitefly resistance. Virus accumulation, whitefly settling behavior, and adult mortality were assessed among multi-resistant lines, a Ty-resistant line, a whitefly-resistant line, and a susceptible check using preference bioassays, controlled inoculation experiments, and acylsugar quantification. Multi-resistant lines exhibited significantly higher acylsugar concentrations, reduced whitefly preference for settling, and increased whitefly adult mortality. Additionally, these lines displayed less severe disease symptoms and lower virus accumulation over time than Ty-resistant, whitefly-resistant, and susceptible controls. These findings highlight the superior efficacy of combined virus and vector resistance in mitigating tomato yellow leaf curl Thailand virus (TYLCTHV) transmission. This research underscores the importance of integrated genetic resistance as a key element of sustainable integrated pest management strategies, offering an environmentally friendly solution for safeguarding global tomato production.