Prevalence and genetic structure of PPV-M in six European contries

International audienceThe prevalence of PPV-M, PPV-D and PPV-Rec strains has been evaluated in 6 European countries (Bulgaria, Czech Republic, France, Serbia, Slovakia and Slovenia). A total of 547 samples have been collected from peach, apricot and plum trees and were characterised directly by PCR-based typing procedures targeting two genomic regions located upstream and downstream the recombination breakpoint located in the Nib gene shared by all PPV-Rec isolates. PPV-M isolates were found predominant in 4 of the 6 countries whereas PPV-Rec was detected in all countries but one. The genetic diversity and structure of PPV-M populations in Europe were evaluated by sequencing 27 isolates coming from 8 countries. The existence of 2 sub-clusters within the PPV-M group has been evidenced. This structure is apparently correlated with the geographical origin of the isolates

An assessment of the transmission rate of four pospiviroid species through tomato seeds

Greenhouse experiments were conducted to investigate the importance of tomato seeds as a route of pospiviroid dissemination. More than 7000 seeds were collected from tomato plants mechanically inoculated with Tomato apical stunt viroid, Citrus exocortis viroid, Columnea latent viroid and Potato spindle tuber viroid. Fruits and part of the seeds were found to be 100 % infected by the inoculated pospiviroid by means of RT-PCR testing. Much of the rest of the seeds were sown and produced about 4700 seedlings. None of the seedlings were found positive for the respective pospiviroid. This shows that pospiviroid seed transmission in tomato is very rare