Publications

4368

Specific scopeThis Standard describes the procedures for inspection of places of production of plants for planting which are susceptible to ‘Candidatus Phytoplasma pyri’. The scope of a place of production inspection may be for export, for internal country movements of materials or as an element of a national survey. Further inspections would be needed to determine freedom of a country or area from the pest concerned. This Standard does not cover eradication or containment measures in infested areas or measures needed to establish and maintain pest‐free places of production within areas where the pest is known to occur. It provides more detailed guidance to supplement EPPO Standard PM 3/76 (1) Trees of Malus, Pyrus, Cydonia and Prunus spp. – inspection of places of production.

AbstractRickettsialesare a lineage of obligatorily intracellularAlphaproteobacteria, encompassing important human pathogens, manipulators of host reproduction, and mutualists. Here we report the discovery of a novelRickettsialesbacterium associated withParamecium, displaying a unique extracellular lifestyle, including the ability to replicate outside host cells. Genomic analyses show that the bacterium possesses a higher capability to synthesize amino acids, compared to all investigatedRickettsiales. Considering these observations, phylogenetic and phylogenomic reconstructions, and re-evaluating the different means of interaction ofRickettsialesbacteria with eukaryotic cells, we propose an alternative scenario for the evolution of intracellularity inRickettsiales. According to our reconstruction, theRickettsialesancestor would have been an extracellular and metabolically versatile bacterium, while obligate intracellularity and genome reduction would have evolved later in parallel and independently in different sub-lineages. The proposed new scenario could impact on the open debate on the lifestyle of the last common ancestor of mitochondria withinAlphaproteobacteria.