Periodic Reporting for period 3 - VOLARE (Scentsitive nature: Green leaf volatile perception in plants and insects)
Periodo di rendicontazione: 2022-02-01 al 2023-07-31
Plant leaves can emit large amounts of volatiles into the air. When attacked by insects, the composition of these blends changes markedly. It is well known that these changes affect not only the behavior of insects interacting with the plant but also the metabolism of the plant itself as well as its nearby competitors. Green leaf volatiles (GLVs) represent a group of plant volatiles emitted the earliest upon herbivory. In earlier research, we discovered a class of enzymes (hexenal isomerases), present in plants and insects, that profoundly affect ecological interactions by converting the highly abundant GLV Z-3-hexenal into E-2-hexenal. These two compounds have distinct effects on the behavior of herbivorous and predacious insects as well as on the metabolism of plants. However, how plants perceive these volatiles and generate a functional response is not known.
The key objectives of the VOLARE project are 1) to mutate plant- and insect-derived hexenal isomerases to understand the role of this enzyme for plant-insect interactions, 2) to identify the molecular mechanisms of E-2-hexenal perception in plants, and 3) to create plants and insects that cannot perceive E-2-hexenal to investigate the role of this volatile in the plant's self-recognition and its role as a signaling molecule for interactions with herbivorous insects and pathogens.
This interdisciplinary research project intends to uncover the perception mechanism of key plant volatile signals and the roles these play in the (eco)physiology of plants and insects. The outcome of this project will greatly expand the fundamental and applied research domain of plant-herbivore interactions as it allows us to perform an in-depth analysis of the biological functions and potential benefits of volatile signaling for improving agro-ecosystems.
The key objectives of the VOLARE project are 1) to mutate plant- and insect-derived hexenal isomerases to understand the role of this enzyme for plant-insect interactions, 2) to identify the molecular mechanisms of E-2-hexenal perception in plants, and 3) to create plants and insects that cannot perceive E-2-hexenal to investigate the role of this volatile in the plant's self-recognition and its role as a signaling molecule for interactions with herbivorous insects and pathogens.
This interdisciplinary research project intends to uncover the perception mechanism of key plant volatile signals and the roles these play in the (eco)physiology of plants and insects. The outcome of this project will greatly expand the fundamental and applied research domain of plant-herbivore interactions as it allows us to perform an in-depth analysis of the biological functions and potential benefits of volatile signaling for improving agro-ecosystems.
We have found several mutant plants in the model species Arabidopsis that are no longer able to respond to the plant volatile E-2-hexenal. We are now investigating which genes are affected by these mutations as these are very promising candidates involved in the perception or the downstream signaling of plant volatiles.
Since not only plants but also insects possess an enzyme that catalyzes the formation of the plant-derived volatile E-2-hexenal, we have created caterpillars of the tobacco hornworm which are unable to produce this enzyme. This means that, when these mutant caterpillars feed on their host plant, they do not initiate the production of increased levels of E-2-hexenal anymore. We are currently investigating whether the mutant caterpillar has a physiological disadvantage if it does not possess the volatile-converting enzyme and how this mutation affects the interaction between plants and insects.
Since not only plants but also insects possess an enzyme that catalyzes the formation of the plant-derived volatile E-2-hexenal, we have created caterpillars of the tobacco hornworm which are unable to produce this enzyme. This means that, when these mutant caterpillars feed on their host plant, they do not initiate the production of increased levels of E-2-hexenal anymore. We are currently investigating whether the mutant caterpillar has a physiological disadvantage if it does not possess the volatile-converting enzyme and how this mutation affects the interaction between plants and insects.
Our goal is to deliver the first non-hormone-related plant receptor for one or more volatile metabolites and to create a rich collection of tools (e.g. mutant plants and insects) that can be used to study how information encrypted in volatile signals is processed by plants. We also aim to gain insight into the robustness of information exchange via such signals and the consequences of signal promiscuity across different trophic levels. Understanding the perception mechanism of non-hormonal plant volatiles, such as E-2-hexenal, could fundamentally change our view on how plants exchange information with their environment.