Calcium availability influences the aggregation and adhesion of Xylella fastidiosa, the causal agent of Pierce's disease in grapes
Notice bibliographique
Résumé
Description Xylem fluid collected from the same grapevine cultivars growing in California and Florida showed significant effects of both cultivar and location on the ratio of calcium/phosphate (Ca/P) as well as pH. It has been reported that calcium bridging is critical for the aggregation and adhesion of X. fastidiosa. Our results showed that under acidic pH (5.5), calcium remains in solution as free ions and X. fastidiosa aggregation is stimulated. In contrast, in basic pH (8.0), calcium phosphate precipitates. In California plants, the Ca/P ratio is close to 1 for Vitis rotundifolia cv. Noble (resistant) and 14.5 for V. vinifera cv. Chardonnay (susceptible). Additionally, the content of acidic pectins, which bind calcium, was higher in the xylem walls of the resistant cultivar Noble. These findings suggest that calcium availability may influence vessel clogging and symptom development in Pierce´s disease. Soil type (composition) may alter the pH of xylem fluid, which in turn may influence calcium availability, thereby impacting aggregation. Results The results identify divalent ions, particularly calcium, as essential factors in the pathogenicity of X. fastidiosa. Calcium binding and calcium bridging are critical during the initial stages of microcolony and colony formation. The availability of calcium and the population density of X. fastidiosa cells within the xylem vessel influence both the quantity and size of aggregates formed. Furthermore, the host plant may regulate this process by removing Ca2+ from the xylem lumen, as observed in the resistant cultivar Noble, which exhibits a higher uronic acid content in its xylem walls. Uronic acid, a form of pectin, is recognized for its capacity to sequester calcium. The mostly negatively charged surfaces of X. fastidiosa cells play a critical role in calcium binding and bridging. The abundance of these negative moieties may correlate with the strain's pathogenicity. Furthermore, Ca2+ mediated cell aggregation could initiate the activation of additional pathogenicity pathways. Xylem fluid composition has been shown to be significant for the development of Pierce’s disease. These findings suggest that management strategies for Pierce’s disease may require a fundamentally new approach. Conclusion Our primary aim is to reestablish homeostatic balance in the host and enhance its innate defense capacity to counter Xylella fastidiosa infection. We investigate plant responses and identify environmental factors that influence xylem sap composition. We seek natural strategies to prevent biofilm formation and subsequent plant infection. Additionally, we intend to collaborate with industry partners to develop eco-friendly solutions that mitigate stress and reduce vessel clogging in plants. Future Directions Ongoing research at the University of Campinas, led by PhD candidate Ayron Andrey da Silva Lima, focuses on developing novel chemically defined media for X. fastidiosa. This work investigates how variations in medium pH influence calcium availability. Acknowledgment: This work received support in its early stages from the American Vineyard Foundation and the California Department of Food and Agriculture, and is now supported by the Nano and Biosystems Laboratory - University of Campinas - Institute of Physics, Gleb Wataghin.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,001 | 0,001 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,001 |
| Études des sciences et des technologies | 0,001 | 0,001 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,001 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».