First Record of White Rust, Caused by <i>Albugo occidentalis</i>, on Spinach in Greece
Notice bibliographique
Résumé
In early December 2012 and February 2013, severe symptoms of white rust were observed on several commercial crops of the spinach (Spinacia oleracea L.) cvs. Tahiti and Rembrandt in the Aghia Pelaghia and Elia areas, respectively, of Heraklio, Crete, Greece. Initially, small, chlorotic lesions developed on the upper side of the leaves. As disease progressed, small, glassy white pustules developed on the underside of each leaf, frequently in concentric rings. The pustules were blister-like and oval, irregularly oval, or elongated, ranging from 0.5 to 2.0 mm in diameter and up to 3 mm in length. Lesions often coalesced, and the pustules could cover the entire lower leaf surface, rendering them unmarketable. The dome-like epidermis of host tissue covering the white rust pustules ruptured and exposed a white, chalky ‘dust’ of numerous powdery spores in small, circular to elongate sori. The sporangia were arranged in basipetal chains, were globose to oval, with a smooth wall that was uniformly thick and measured 19.1 ± 1.93 (14.1 to 23.5) μm × 15.3 ± 1.49 (12.9 to 20.0) μm when hydrated. Oospores were absent from the leaves. The morphological characteristics closely resembled those reported for the white rust pathogen, Albugo occidentalis Wilson (4), as well as those of A. occidentalis measured from dried leaves of Chenopodium spp. and Monolepis nuttalliana (Schult.) Greene (Herb. IMI96980, IMI351202, and IMI26345, respectively), kindly loaned by the Royal Botanic Gardens, Kew, United Kingdom. Pathogenicity was confirmed by spraying a suspension of 10 5 sporangia/ml on 10 healthy 20-day-old potted spinach plants of cv. Tahiti. Inoculated plants were covered with polyethylene bags for 3 days and incubated in a growth chamber at 16 to 20°C with a 10-h photoperiod. White rust symptoms were observed on the lower surface of the leaves 10 days after inoculation. Ten control plants sprayed similarly with distilled water and maintained under the same conditions as inoculated plants showed no symptoms. The fungus present on the inoculated plants was morphologically identical to that originally observed on diseased plants, fulfilling Koch's postulates. Genomic DNA from spinach leaf sori was extracted, and the internal transcribed spacer (ITS) region of ribosomal DNA (rDNA), ITS1-5,8S-ITS2, as well as the cytochrome oxidase subunit II (COX2) mitochondrial gene, were amplified. PCR products were sequenced and deposited in GenBank (KC676794 and KC676795, respectively). In a BLAST search, the ITS1-5,8S-ITS2 and COX2 sequences showed 99% similarities to 684 bp (AJ553900.1) and 599 bp (AY286220.1) sequences of the corresponding A. occidentalis genes in GenBank, respectively. Based on morphological characteristics, pathogenicity tests, and molecular sequencing data, it was concluded that the pathogen on spinach in Crete is A. occidentalis. This is an economically important pathogen of spinach in the United States, that has also has been recorded in Iran (2) and India on a Chenopodium sp. (IMI351202), and in Canada on M. nuttalliana (IMI26345). To our knowledge, this is the first report of this pathogen in Greece, and the first record on spinach in Europe. A voucher specimen has been deposited at the Royal Botanic Gardens, Kew, United Kingdom (Accession No. K(M) 181610). References: (1) J. C. Correll et al. Eur. J. Plant Pathol. 129:193, 2011. (2) A. G. Ebrahimi and H. Afzali. Rostaniha 1:73, 2000. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN, 1989. (4) G. W. Wilson. Bull. Torrey Bot. Club 34:61, 1907.
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 | 0,000 | 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) | 0,000 | 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 ».