Exploring the hydraulic failure hypothesis of esca leaf symptom formation
BADEL, Eric
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
CHARRIER, Guillaume
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
COCHARD, Hervé
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
TORRES RUIZ, Jose Manuel
Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
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Laboratoire de Physique et Physiologie Intégratives de l’Arbre en environnement Fluctuant [PIAF]
Langue
en
Article de revue
Ce document a été publié dans
Plant Physiology. 2019, vol. 181, n° 3, p. 1163-1174
Oxford University Press ; American Society of Plant Biologists
Résumé en anglais
Vascular pathogens cause disease in a large spectrum of perennial plants, with leaf scorch being one of the most conspicuous symptoms. Esca in grapevine (Vitis vinifera) is a vascular disease with huge negative effects on ...Lire la suite >
Vascular pathogens cause disease in a large spectrum of perennial plants, with leaf scorch being one of the most conspicuous symptoms. Esca in grapevine (Vitis vinifera) is a vascular disease with huge negative effects on grape yield and the wine industry. One prominent hypothesis suggests that vascular disease leaf scorch is caused by fungal pathogen-derived elicitors and toxins. Another hypothesis suggests that leaf scorch is caused by hydraulic failure due to air-embolism, the pathogen itself, and/or plant-derived tyloses and gels. In this study we transplanted mature, naturally infected esca symptomatic vines from the field into pots, allowing us to explore xylem integrity in leaves (i.e. leaf mid-veins and petioles) using synchrotron-based in vivo X-ray micro-computed tomography and light microscopy. Our results demonstrated that symptomatic leaves are not associated with air embolism. In contrast, symptomatic leaves presented significantly more non-functional vessels resulting from the presence of non-gaseous embolisms (i.e. tyloses and gels) than control leaves, but there was no significant correlation with disease severity. Using quantitative PCR, we determined that two vascular pathogen species associated with esca necrosis in the trunk were not found in leaves where occlusions were observed. Together these results demonstrate that symptom development is associated with the disruption of vessel integrity and suggest that symptoms are elicited at a distance from the trunk where fungal infections occur. These findings open new perspectives on esca symptom expression where the hydraulic failure and elicitor/toxin hypotheses are not necessarily mutually exclusive.< Réduire
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