Phylogeny and taxonomy of the genera of Erysiphaceae, part 3: .

This contribution is part of a series devoted to the phylogeny and taxonomy of powdery mildews, with an emphasis on North American taxa. An overview of species is given, including references to ex-type sequences or, if unavailable, proposals for representative reference sequences for phylogenetic-taxonomic purposes. The new species is described, based on Mexican collections on × and × is reported for the first time worldwide on (Collected in Mexico) and on (collected in Arizona, USA).

Antagonism or synergism between papaya ringspot virus and papaya mosaic virus in Carica papaya is determined by their order of infection.

Antagonism between unrelated plant viruses has not been thoroughly described. Our studies show that two unrelated viruses, papaya ringspot virus (PRSV) and papaya mosaic virus (PapMV) produce different symptomatic outcomes during mixed infection depending on the inoculation order. Synergism occurs in plants infected first with PRSV or in plants infected simultaneously with PRSV and PapMV, and antagonism occurs in plants infected first with PapMV and later inoculated with PRSV.

The absence of eukaryotic initiation factor eIF(iso)4E affects the systemic spread of a Tobacco etch virus isolate in Arabidopsis thaliana.

Translation initiation factor eIF4E exerts an important role during infection of viral species in the family Potyviridae. Particularly, a eIF(iso)4E family member is required for Arabidopsis thaliana susceptibility to Turnip mosaic virus, Lettuce mosaic virus, and Tobacco etch virus (TEV). In addition, a resistance mechanism named restriction of TEV movement (RTM) in A.