New insights supporting the contribution of carotenoids to the resistance of maize to Gibberella ear rot and deoxynivalenol contamination - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement
Conference Papers Year : 2023

New insights supporting the contribution of carotenoids to the resistance of maize to Gibberella ear rot and deoxynivalenol contamination

Abstract

Most of the knowledge related to the role of secondary metabolites in plant defense response against fungal phytopathogens has focused hitherto on phenylpropanoids and very few is known regarding the potential involvement of lipophilic antioxidants, notably of carotenoids. And yet, there are strong theoretical arguments indicating that these metabolites could play a key role in maize resistance to fungal diseases including Gibberella Ear Rot (GER)1 and contamination of grains with mycotoxins such as deoxynivalenol (DON): involvement in resistance to abiotic stresses, ability to quench reactive oxygen species, implication in the mediation of plant response signaling. The present study aims to investigate the potential contribution of carotenoids to the chemical defense employed by maize to counteract F. graminearum using a double approach associating in planta and in vitro studies. As a first step, a two-year analysis of the carotenoid contents of 33 genotypes showing different levels of GER susceptibility has led to evidence significantly higher levels of zeaxanthin and β-cryptoxanthin in susceptible genotypes compared to tolerant ones, suggesting that these two carotenoids could be biochemical markers of susceptibility of maize to GER. In a second step, supplementation of carotenoid extracts in cultures inoculated with F. graminearum has led to a significant inhibition of the production of DON. Further analysis has suggested that zeaxanthin could be the key actor of this inhibition efficiency, notably via a negative control of the expression of several DON biosynthetic genes. Besides, exposition to zeaxanthin was demonstrated to induce profound perturbations in the fungal redox homeostasis by affecting the expression of various genes, some of them encoding enzymes known to contribute to F. graminearum virulence2. Altogether, our data led to apparently contradictory conclusions: carotenoids facilitate or hamper F. graminearum disease? They illustrate the complexity of interactions possibly occurring between carotenoids in grains and F. graminearum and highlight the necessity to implement integrative research considering all the potential physiological roles of carotenoids.
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hal-04134947 , version 1 (20-06-2023)

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  • HAL Id : hal-04134947 , version 1

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Jean-Marie Savignac, Stéphane Bernillon, Véronique Ortéga, Christine Ducos, Nathalie Gallegos, et al.. New insights supporting the contribution of carotenoids to the resistance of maize to Gibberella ear rot and deoxynivalenol contamination. EFS16 16th European Fusarium Seminar, Sapienza University of Rome, Jun 2023, Rome, Italy. ⟨hal-04134947⟩
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