Involvement and contribution to virulence of Endo-Beta-1,4-Xilanases of Fusarium Graminearum during host infection
Notice bibliographique
Résumé
Fusarium graminearum is the fungal pathogen mainly responsible for Fusarium head blight (FHB) of cereal crops, which attacks wheat spikes, reducing crop production and quality of grain by producing trichothecene mycotoxins. Several cytohistological studies showed that spike infection is associated with the production of cell wall degrading enzymes. Wheat tissue, as in other commelinoid monocot plants, is particularly rich in xylan which can be hydrolyzed by fungal endo-β-1,4-xylanase. The FGSG_03624 is one of the most expressed xylanase genes in wheat spikes 3 days after inoculation and was heterologously expressed in the yeast Pichia pastoris. The recombinant protein (22.7 kDa) possessed xylanase activity and induced cell death and hydrogen peroxide accumulation in wheat leaves infiltrated with 10 ng/μl or in wheat glume surface treated with 20 ng/μl. This effect reflects that observed with other described fungal xylanases (from Trichoderma reesei, T. viride and Botrytis cinerea) with which the FGSG_03624 protein shares a stretch of amino acids reported as essential for elicitation of necrotic responses. Several F. graminearum mutants with the FGSG_03624 gene disrupted were obtained, and showed about 40% reduction of total xylanase activity in comparison to the wild type when grown in culture with xylan as carbon source. Even if the FGSG_03624 xylanase is able to induce hypersensitive-like symptoms on a monocot plant, FGSG_03624 gene deletion mutants were fully virulent on wheat cvs. Bobwhite and Nandu, probably because of xylanase gene redundancy. Therefore the role of this xylanase during wheat infection remains elusive. To get insight about the importance of xylanase activities produced by the pathogen during infection of host plants, Xyr1, a transcriptional regulator factor putatively regulating the expression of several xylanase genes has been deleted by targeted homologous recombination. Deleted mutants of the FGSG_17662 gene, encoding Xyr1, were heavily impaired both in total secreted xylanase activity and in fungal biomass formation when grown in liquid culture with xylan as sole carbon source. In comparison to WT, the fungal dry weight was reduced, by 40% to 70% and the total xylanase activity was reduced by about 90%. F. graminearum Xyr1 deletion mutants are now available to be submitted to expression analysis in vivo to verify the Xyr1 mediated regulation of the expression of genes encoding for xylanolitic enzymes during plant infection. The Xyr1 disrupted mutants will be characterized for their virulence by inoculating Triticum aestivum spikes. If these mutants will be verified as impaired in virulence, in planta overexpression of xylanase inhibitors may be considered as a new tool to control FHB
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 machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| 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 source (Gemma direct ou Codex distillé), 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 ».