Insight on the inside: exploring natural variation in phloem-based metabolites for insect resistance

Informations

Funding country

Netherlands

Acronym

-

URL

-

Start date

7/1/2020

End date

-

Budget

284,102 EUR

Fundings

Abstract

The mandatory reduction in systemic pesticide usage drives the development of alternative methods for crop protection against herbivorous insects. Genetic resistance, as part of integrated pest-management, has big potential to be a durable solution. Metabolic resistance, plant-produced specialised metabolites with a defence effect on insects, could be the basis of an approach where we shift from using high concentrations of synthetic pesticides to plants producing their own defensive chemistry. In fact, in wild ancestors such mechanisms are readily found. Specialised metabolites are known to play a pivotal role in plant-herbivore interactions and there is an incredible natural diversity of compounds present in plants. Such compounds vary from small volatile terpenes to complex decorated molecules. In many plant species these compounds are produced, stored and secreted in specialised tissues, in order to defend themselves against attacking pathogens and insects. The lab in Amsterdam has a strong background in studying the production and regulation of specialised compounds, in relation to plant health, both above- as well as belowground. Production of specialised metabolites in specific tissues, such as glandular trichomes is effective, as such glands are geared to be “metabolic factories”. However, trichome-based resistance can have off-target effects on beneficial insects such pollinators and natural enemies of pest insects. In addition to “outside” produced specialised compounds, it is known that the phloem sap, besides photosynthates, also harbours a plethora of specialised metabolites including glycosylated terpenes, glucosinolates, triterpenoids and flavonoids. The aim of this proposal is to explore the phloem as another site of defence against insects that feed specifically from the phloem, including relevant pest-insects to agriculture (whiteflies, aphids). The focus of this study into phloem-associated defence mechanisms is specifically on phloem-based metabolites that affect insect proliferation. We will set out to explore the natural variation in the tomato germplasm in resistance against phloem feeders and perform an untargeted metabolomics approach to search for differences in host-plant chemistry. The phloem is a very specific environment and the phloem metabolism (and function) will be affected by its low internal oxygen state. Environmental perturbations will be a major complicating factor that influences the quality and quantity of specialised-metabolite production. Therefore, we would like to study the effect of perturbations such as insect attack, oxidative stress and temperature on the metabolic fingerprints of selected interesting material, and associate these to insect-response phenotypes. Finally, we aim for the identification of underlying genes that, in combination with metabolites causal to resistance, will serve as biochemical and molecular markers for the development of novel resistant tomato varieties.