Mapping the phytoplasma chromosome

Physical and genetic mapping of the phytoplasma chromosome can be a useful tool in a genome sequencing project in order to assemble the in silico-predicted contigs robustly. Mapping consists of four distinct steps: preparation of phytoplasma chromosomes from infected plants, single- and double-digestion of chromosomes with rare-cutting restriction enzymes, separation of large DNA fragments by pulsed-field gel electrophoresis, and hybridization with various genetic markers. Materials and methods needed for each step are described and the technique is illustrated using the flavescence doree phytoplasma genome map as an example

Purification of phytoplasma DNA for sequencing the “flavescence dorée” and stolbur phytoplasma genomes

International audienc

Multiplication kinetics of Flavescence dor,e phytoplasma in broad bean. Effect of phytoplasma strain and temperature

The multiplication kinetics of the Flavescence dor,e phytoplasma in broad bean after inoculation by the experimental vector Euscelidius variegatus was determined. The number of phytoplasma cells, measured by quantitative real-time PCR in the aerial parts of the plants, increased exponentially over the time. After 22 to 30 days post inoculation, when symptoms appeared, bacterial growth reached a stationary phase. Whatever the time following inoculation there were no statistical differences between numbers of phytoplasma cells in plants infected by Map-FD1 (FD-CAM05) and Map-FD2 (FD92 and FD-PEY05) genotype strains. On the contrary, temperature had an influence on Flavescence dor,e phytoplasma multiplication which was nearly twice as fast in broad beans incubated at 25 A degrees C than in broad beans incubated at 20 A degrees C. At 25 A degrees C, plants expressed symptoms 1 week earlier. In a context of climate change, the consequences of a global warming on the Flavescence dor,e epidemics are discussed

Detection and diversity of “flavescence dorée” related phytoplasmas in alders surrounding infected vineyards in Aquitaine (France)

International audienc