Metabolism of plant chemical defenses by herbivore insects: ecology, chemistry, biochemistry and evolution

• Grant number: 22/03249-9
• Support Opportunities: Research Grants - Initial Project
• Start date: February 01, 2023
• End date: January 31, 2028
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Principal Investigator: Felipe Christoff Wouters
• Grantee: Felipe Christoff Wouters
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil

Abstract

The fascinating biodiversity of plants and insect herbivores and their coexistence for at least 350 million years have originated hypotheses pointing to the coevolution of these organisms based on plant secondary metabolites used as chemical defenses. While plants have developed novel chemical defenses throughout their evolutionary history, insects have developed adaptations that allowed them to feed on such plants. The repetition of these events drives the evolution of both insect herbivores and plants, establishing the so-called "coevolutionary arms race". Despite being an intuitive and popular model, the concept of coevolution still lacks clear mechanisms and remains difficult to prove. This project has the goal of investigating the metabolism of plant chemical defenses by insect herbivores, using soybean flavonoids and herbivore caterpillars as a model system. The main biochemical pathways employed by insects in order to metabolize and detoxify such chemical defenses are going to be investigated, as well as the chemical structures of the resulting metabolites and sequences of implicated genes and enzymes. Bioassays with plants and insects are going to be used to quantify the toxicity of these compounds and evaluate the dynamics of these defenses in plants. Molecular data are going to be used to investigate enzymatic activities through heterologous expression, and to follow the evolution of these enzyme families in Lepidoptera, comparing it to host plant preferences for other genera and families within this order. This multidisciplinary approach has the potential of raising new hypotheses to test the coevolution of plants and insect herbivores and shedding light on its mechanistic framework. (AU)