engleski

Multilocus sequence analysis reveals the genetic diversity of European fruit tree phytoplasmas and the existence of inter species recombination

The genetic diversity of three temperate fruit tree phytoplasmas ; ‘Candidatus Phytoplasma prunorum’, ‘Ca. P. mali’ and ‘Ca. P. pyri’ has been established by multilocus sequence typing. Among four genetic loci the genes imp and aceF showed the highest variability as they allowed distinguishing 30 and 24 genotypes respectively among the three species. Phylogentic analyses were in agreement with the existence of the three described species. The highest diversity was obtained with imp with divergence in the range of 50 to 68 % according to species. Percentage of substitution varied between 9 to 12 % for aceF, whereas it was 5-6 % for pnp and secY. In the case of ‘Ca P. prunorum’ the three most prevalent aceF genotypes were detected both in plants and in insect vectors, confirming the prevalent isolates to be propagated by insects. The four hypovirulent isolates had the same aceF sequence indicating a possible monophyletic origin. Haplotype distribution revealed that among the 34 haplotypes of ‘Ca. P. prunorum’, the four hypovirulent isolates grouped again together on the same branch. Genotyping of some Spanish and Azerbaijanese ‘Ca. P. pyri’ isolates showed they shared some makers with ‘Ca. P. prunorum’ demonstrating for the first time the existence of inter-species recombination between this two species.

‘Candidatus Phytoplasma prunorum’; ‘Ca. P. mali’; ‘Ca. P. pyri’; gene loci imp; aceF; pnp; secY

Rad je rezultat suradnje na projektu SEE-ERANET "Global epidemiology of phytoplasma diseases of economical importance in southeastern Europe" iz okvirnog programa FP6.