The Impact of Rhizobacteria on Direct and Indirect Tomato Resistance to Tuta absoluta - Part 1

• Grant number: 25/05081-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Plant Health
• Principal Investigator: José Maurício Simões Bento
• Grantee: Flávia Pereira Franco
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil
• Associated research grant: 24/15548-6 - Chemical and molecular ecology in the study of multitrophic interactions for the management of Tomato Leafminer, AP.PFPMCG.TEM

Abstract

The cultivated tomato (Solanum lycopersicum) and its wild relatives originate from the Andean valleys of South America. While cultivated tomatoes are one of the most economically important vegetable crops, they have undergone a genetic bottleneck that reduced their diversity, leading to the loss of important resistance traits found in wild species like Solanum habrochaites. These wild relatives serve as valuable sources of genetic material for breeding programs, offering resistance to herbivores and other stress factors. One of the most significant threats to tomato production worldwide is the South American tomato pinworm, Tuta absoluta, a specialist leaf-miner that is difficult to control with insecticides due to its feeding behavior within leaf mesophyll. As a result, sustainable pest management strategies are necessary. Biological control using natural enemies such as Macrolophus basicornis, a zoophytophagous mirid predator, and Trichogramma pretiosum, an egg parasitoid, has shown promise. Studies indicate that combining these natural enemies can significantly reduce T. absoluta populations, offering an eco-friendly alternative to chemical insecticides. Previous research demonstrated that inoculating tomato plants with the plant growth-promoting rhizobacterium (PGPR), Bacillus amyloliquefaciens GBO3, enhanced both plant development and defense mechanisms. PGPR-inoculated plants exhibited increased biomass, higher densities of glandular and non-glandular trichomes, elevated jasmonic acid levels, and enhanced volatile organic compound (VOC) emissions. These VOCs influenced the behavior of M. basicornis, with predators showing a clear preference for PGPR-inoculated plants in olfactometer assays. This project aims to explore how different rhizobacterial species impact tomato plant performance, identifying those that provide the most effective direct and indirect resistance against T. absoluta. The objectives include selecting rhizobacteria that enhance plant growth, reduce herbivore feeding, and increase attractiveness to natural enemies. After identifying the most effective strains, RNA sequencing will be conducted to uncover specific targets related to tomato plant defense mechanisms.