Distribution of carnation viruses in the shoot tip: Exclusion from the shoot apical meristem

Cell biological tools were used to localize the genomic RNAs/DNA and/or the coat protein (CP) of Carnation mottle, Carnation vein mottle, Carnation latent, and Carnation etched ring viruses in the carnation shoot tip to know whether any of them was capable of infecting the shoot apical meristem. Our results showed that all the viruses studied were excluded not only in single-infected but also in double-infected plants. Despite that, these viruses showed a different infection pattern inside the shoot tip, with different cell types being their main targets. For the mixed infection studied here, our results showed the existence of a spatial separation pattern within the carnation shoot tip which strongly suggests an exclusion phenomenon.