PRIN 2022 - COD. 2022BKBMLM - "LISCL-mediated catabolism regulates plant-environment interactions" - Finanziamento dell’Unione Europea – NextGenerationEU – missione 4, componente 2, investimento 1.1.

Living organisms are embedded in their environment from which they continuously receive stimuli, and integrate hundreds of signals to achieve positive interactions and ensure growth and reproduction. Plants are particularly dependent on their environment due to their inability to move, and have evolved molecular mechanisms to ensure specific responses to both abiotic stimuli, such as light and water availability, and biotic ones, such as those imposed by hostile organisms or symbiotic interactions. Molecular messengers, both of endogenous origin, such as phytohormones, and of exogenous origin, usually referred to as elicitors, mediate these interactions. Uncontrolled accumulation of these molecules can cause toxicity, and organisms in all kingdoms have evolved detoxification mechanisms. In Arabidopsis, SCL14-dependent 'xenobiotic detoxification' is a pyramidal pathway involving transcription factors, enzymes and transporters, ensuring the modification, conjugation and compartmentalization of phytohormones, signalling molecules and toxic compounds. The goals of this project are twofold: to discover which molecules undergo SCL14-regulated detoxification and to study the role of SCL14 and its homologues (LISCL family) in plant-environment interactions and stress response. To achieve these objectives, we have established a collaboration between three research units. Their respective expertise in metabolite biochemistry, plant physiology and plant/soil microbiome will allow a wide-ranging analysis of the role of LISCL proteins. First, we will assess the involvement of LISCL family members in the detoxification pathway. We will use LISCL mutants, compromised in catabolism, to study the molecular signalling that occurs under salt and drought stress. Indeed, it has already been shown that scl14 mutants accumulate higher levels of both signalling and damaging molecules. Next, we will identify the palette of molecules that induce the detoxification pathway by screening a library of chemicals on a reporter line. The effect of the identified and commercially available LISCL-inducing molecules on Arabidopsis growth and stress resilience will be tested in vitro. Among LISCL elicitors, β-cyclocitral and other apocarotenoids have already demonstrated strong activity as biostimulants, increasing plant tolerance to stress and regulating root growth. Their effects on the plant rhizobiome and arbuscular mycorrhizae development will be analyzed on Solanum lycopersicum in field, under control and salt stress conditions. Finally, the molecular mechanisms underlying these responses will be studied by analyzing the response of SCL14 and ANAC102 to LISCL-inducing molecules. Achieving the project goals will enrich our knowledge of the molecular mechanisms of plant stress resilience and rhizo-biotic interactions, and will allow us to identify molecules potentially useful as biostimulants.