Le virus de la striure de l'arachide

Le virus de la striure de l'arachide (peanut stripe virus ou PStV) appartient au groupe des potyvirus. Il se transmet mécaniquement, par les pucerons (de manière non persistante) et par les graines de l'arachide (Arachis hypogaea). Le PStV infecte l'arachide naturellement en Chine, en Inde, en Indonésie, en Malaisie, au Myanmar, aux Philippines, en Thaïlande, aux Etats-Unis et au Vietnam. Les symptômes induits chez l'arachide varient selon les isolats différents du PStv. Des antisérums ont été produits pour plusieurs isolats du PStV et des tests sérologiques sont disponibles pour la détection du virus au niveau des feuilles et des graines. D'après la sérologie et le profil peptidique de la protéine de capside, le PStV est apparenté à la mosaïque du niébé (blackeye cowpea mosaic virus). Des études sur l'organisation génomique du PStV au niveau moléculaire ont été initiées. Les données disponibles jusqu'à maintenant laissent croire que ce virus est étroitement lié au virus de la mosaïque du soja, au virus de la mosaïque de la pastèque (watermelon mosaic virus) et au virus de la mosaïque jaune de la courgette d'Italie (zucchini yellow mosaic virus). Les mesures de lutte contre la maladie sont examinées sur la base des informations épidémiologiques disponible

Le virus de la striure de l'arachide

Background: Further research on effective interventions for patients with peristent Medically Unexplained Physical Symptoms (MUPS) in general practice is needed. Prevalence estimates of such patients are conflicting, and other descriptive knowledge is needed for development and evaluation of effective future interventions. In this study, we aimed to estimate the consultation prevalence of patients with persistent MUPS in general practice, including patients’ characteristics and symptom pattern, employment status and use of social benefits, and the general practitioners’ (GPs) management strategy. Method: During a four-week period the participating Norwegian GPs (n = 84) registered all consultations with patients who met a strict definition of MUPS (>3 months duration and function loss), using a questionnaire with simple tick-off questions. Analyses were performed with descriptive statistics for all variables and split analysis on gender and age. Results: The GPs registered 526 patients among their total of 17 688 consultations, giving a consultation prevalence of persistent MUPS of 3%. The mean age of patients was 46 years, and 399 (76%) were women. The most frequent group of symptoms was musculoskeletal problems, followed by asthenia/fatigue. There was no significant gender difference in symptom pattern. Almost half of the patients were currently working (45%), significantly more men. The major GP management strategy was supportive counseling. Conclusion: A consultation prevalence rate of 3% implies that patients with persistent MUPS are common in general practice. Our study disclosed heterogeneity among the patients such as differences in employment status, which emphasizes the importance of personalized focus rather than unsubstantiated stereotyping of “MUPS patients” as a group.publishedVersio

Stock indexing and Potato virus Y elimination from potato plants cultivated in vitro Indexação de matrizes e eliminação do Potato virus Y em plantas de batata cultivadas in vitro

Potato cultivars (Solanum tuberosum L.) have shown degeneration or run out caused by viruses after several cycles of propagation using seed tubers from commercial fields. This work reports the occurrence of single and mixed infections of four potato viruses in Paraíba-Brazil and presents a method for Potato virus Y (PVY) elimination, by using thermo-and chemotherapies. Plants of potato cv. Baraka were tested by direct antigen coating ELISA. Antisera against PVY, Potato virus X (PVX), Potato virus S (PVS), and Potato leafroll virus (PLRV) were used. Materials with positive reaction to PVY were treated for virus elimination. Single node cuttings (1.0 cm length) were excised and inoculated in Murashige & Skoog (MS) medium, supplemented with 1.0 mg L-1 of kinetin, 0.001 mg L-1 of naphthalene acetic acid (NAA) and 0.1 mg L-1 of gibberellic acid (GA3). The thermotherapy at approximately 37ºC, during 30 and 40 days, resulted in 20.0 and 37.5% PVY elimination, respectively. Chemotherapy was undertaken with Ribavirin (RBV), 5-Azacytidine (AZA), and 3-Deazauridine (DZD). The RBV showed the highest rate of virus eradication, with 55.5% virus-free plants. Simultaneous thermo and chemotherapy had higher efficiency for the elimination of PVY, reaching rates of healthy plants of 83.3% with RBV, 70.0% with AZA, and 50.0% with DZD.<br>Cultivares de batata (Solanum tuberosum L.) têm mostrado degenerescência causada por vírus após ciclos sucessivos do uso de tubérculos de campos comerciais como material propagativo. Este trabalho verifica a ocorrência de infecção simples e mista de quatro vírus da batata na Paraíba e apresenta adequação da técnica de cultivo in vitro para obtenção de material livre de Potato virus Y (PVY), incluindo uso de microestacas, termo e quimioterapia. Plantas de batata do cv. Baraka foram submetidas à indexação sorológica pelo teste "direct antigen coating" ELISA. Utilizaram-se antissoros contra o PVY, Potato virus X (PVX), Potato virus S (PVS) e Potato leafroll virus (PLRV). Materiais com reação positiva para PVY foram submetidos a tratamentos visando à eliminação viral. Microestacas (1,0 cm de comprimento) com uma gema foram excisadas e inoculadas em meio nutritivo de Murashige & Skoog (MS), suplementado com 1,0 mg L-1 de cinectina, 0,00l mg L-1 de ácido naftaleno acético (ANA) e 0,1 mg L-1 de ácido giberélico (GA3). Termoterapia a 37ºC, durante 30 e 40 dias, promoveu a eliminação do PVY em 20,0 e 37,5% no material testado, respectivamente. A quimioterapia foi realizada com Ribavirin (RBV), 5-Azacitidina (AZA) e 3-Deazauridine (DZD). O RBV apresentou os melhores índices de erradicação de vírus com a obtenção de 55,5% de plantas sadias. Tratamentos simultâneos de termo e quimioterapia mostraram maior eficiência na eliminação viral, atingindo um percentual de plantas sadias da ordem de 83,3 com RBV, 70,0 com AZA e 50,0 com DZD