Virus de l'enroulement de la pomme de terre : le point sur les recherches

National audienc

Production of recombinant Potato mop-top virus coat protein in Escherichia coli and generation of antisera recognising native virus protein

Copyright © 2003 Elsevier Science B.V. All rights reservedPotato mop-top virus (PMTV, Pomovirus) is difficult to detect because it is unevenly distributed and present at low concentration in infected tissues. The production of PMTV-free seed relies on sensitive and specific detection methods of virus detection, including serological methods. The possibility of using a PMTV recombinant coat protein (CP) as an antigen for antiserum production was investigated. The region encoding the PMTV CP was inserted into pET3A, expressed in Escherichia coli, and the recombinant PMTV CP produced was used to raise antibodies in rabbits. Three antisera were produced. All recognised efficiently the recombinant CP in Western blot analysis and the most sensitive antiserum (H5003) detected native CP on Western blots and in ELISA. Thus, recombinant CP can be used as an alternative to purified virus for the production of specific antibodies against PMTV.Valérie Hélias, Emmanuel Jacquot, Maryse Guillet, Yves Le Hingrat and Danièle Giblot-Ducrayhttp://www.elsevier.com/wps/find/journaldescription.cws_home/506080/description#descriptio

Distribution of Cardicola forsteri eggs in the gills of southern bluefin tuna (Thunnus maccoyii) (Castelnau, 1872)

The distribution of Cardicola forsteri eggs in the gills of southern bluefin tuna (Thunnus maccoyii) was analysed. Eggs were confirmed to be C. forsteri using laser-capture microdissection and quantitative polymerase chain reaction (qPCR) analyses. Prevalence of infection was significantly higher in the second gill arch (χ2 = 6.49, P < 0.05) than in the fourth gill arch, and significantly lower in the basal region of the second gill arch (χ2 = 6.29, d.f. = 2, P < 0.05). The intensity of infection was not significantly different between the gill arches (F = 0.03, d.f. = 1, P > 0.05). Similarly, there was no significant difference in the intensity of C. forsteri eggs between the gill arches (F = 3.43, d.f. = 2, P > 0.05), or at different depth of sectioning (F = 0.08, d.f. = 1.12, P > 0.05). Results suggest that the presence of C. forsteri eggs in the gills of tuna is more likely to be detected by sampling the second gill arch. Furthermore, targeting the middle region and increasing the sectioning depth may reduce the proportion of false negatives

Detection of grape phylloxera (Daktulosphaira vitifoliae Fitch) by real-time quantitative PCR: development of a soil sampling protocol

Background and Aims: Quantitative PCR (qPCR) provides the basis for an efficient detection and surveillance system for phylloxera, a devastating pest of grapevines worldwide. This study aimed to develop a sample collection and handling protocol for reliable detection of phylloxera in soil by qPCR. Methods and Results: Quantitative PCR conducted on infested soil samples stored at 10, 20 or 35°C for up to 10 days showed that extended storage did not significantly affect the rate of phylloxera detection. The limit of detection of qPCR was estimated to be 1.5 to 2 phylloxera per 200 g dry soil using samples prepared from phylloxera‐infested and non‐infested soil in various ratios. Comparison of phylloxera detection rate and numbers between depths, positions and vineyards, in all seasons over 2 years showed that the highest detection rate is obtained with samples taken 0–10 cm deep and 5 cm from the trunk, and that higher numbers are consistently found from mid‐summer to early winter. Conclusions: When combined with an appropriate sampling protocol, qPCR allows reliable detection of phylloxera in soil, across sites and seasons. Significance of the Study: The sampling protocol developed in this study will facilitate the adoption of qPCR for large scale monitoring and surveillance of phylloxera by the industry.D. Giblot‐Ducray, R. Correll, C. Collins, A. Nankivell, A. Downs, I. Pearce, A. C. Mckay, K. M. Ophel‐Kelle