Etude de l'activation du rétrotransposon de tabac Tnt1 au cours d'interactions plante-pathogène

National audienc

Activation du retrotransposon de tabac Tnt1 lors de la mise en place des réponses de défense des plantes

National audienc

Quasispecies in retrotransposons: A role for sequence variability in Tnt1 evolution

4 graph.International audienc

The mobility of the tobacco Tnt1 retrotransposon correlates with its transcriptional activation by fungal factors

51 ref.International audienc

Molecular and functional characterization of Slide, an Ac-like autonomous transposable element from tobacco

International audienc

The mobility of the tobacco Tnt1 retrotransposon correlates with its transcriptional activation by fungal factors

51 ref.International audienc

Functional analysis of the tobacco Tnt1 retrotransposon

International audienc

An accurate real-time PCR test for the detection and quantification of cauliflower mosaïc virus (CaMV):applicable in GMO screening

International audienceDue to its very large use in the first generation of genetically modified organisms (GMO), the 35S promoter derived from the cauliflower mosaic virus (CaMV) is the most used PCR target for screening tests in GMO routine analysis, before any identification and quantification of GMOs. Accordingly, a specific detection of the virus donor organism is required to avoid false positives. A new qualitative and quantitative method based on real time polymerase chain reaction (PCR) techniques was developed for the detection and quantification of CaMV. The region targeted was an internal part of a qualitative test previously published using the ORFIII of the CaMV genome. It codes for a protein (P3) responsible for the pathogen infectivity and not in the ORFIV coding for a coat protein (P4), which can be used for GMO constructions. In this paper, we show the high reliability of the PCR test both in simplex and duplex (with P35S of the CaMV). This test shows high specificity and sensitivity (LODa ≤ 10 copies and LOQa ≤ 100 copies). Advantages and drawbacks of this test with a previously published test are discussed. Finally, the ORFIII PCR product was cloned in a pGEM-T vector for further use in the near future as an alternative calibrant for quantitative analyses through its availability from the international BCCM/LMBP Ghent plasmid ban

Genetic and biochemistry analyses of the natural resistance to the fungicide fenhexamid in the phytopathogenic fungus Botrytis pseudocinerea

The Botrytis species complex responsible for grey mould disease on grapevine is composed of two species: Botrytis cinerea the major one (about 90%) and Botrytis pseudocinerea. Despite their genetic polymorphism, these species cannot be morphologically distinguished. However, they do differ in their response to several fungicides, especially to the sterol biosynthesis inhibitor fenhexamid. While B. cinerea is sensitive to this hydroxyanilide, B. pseudocinerea is naturally resistant. Enzyme assays showed that in B. pseudocinerea the fenhexamid target enzyme, the sterol 3-ketoreductase was less sensitive to fenhexamid. In addition, a strong synergism between fenhexamid and sterol 14α-demethylation inhibitors (DMIs) known to inhibit Cyp51, a cytochrome P450 monooxygenase was observed in B. pseudocinerea. These results could suggest detoxification of fenhexamid by cytochromes P450. The cyp684 gene showing the strongest similarity to cyp51 among all B. cinerea cytochrome P450 genes was found strongly overexpressed in the presence of fenhexamid in B. pseudocinerea. In this work, we studied separately the effect of B. pseudocinerea erg27 polymorphism, erg27 encoding 3-ketoreductase, and of the recently identified cytochrome P450 gene, cyp684, on resistance to fenhexamid, respectively by erg27 gene, and cyp684 inactivation. In parallel, metabolization studies are conducted to identify metabolites and test their activity on Botrytis spp