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

ARTICLE IN PRESS0885-5765/$ - se doi:10.1016/j.pm Correspond E-mail addr 1These autho 2Permanent Plantas, UPV-CPhysiological and Molecular Plant Pathology 69 (2006) 43–51 /locate/pmppDistribution of carnation viruses in the shoot tip: Exclusion from the shoot apical meristem B. Gosalvez-Bernal1, S. Garcia-Castillo1, V. Pallas2, M.A. Sanchez-Pina Departamento de Biolog??a del Estre?s y Patolog??a Vegetal, CEBAS (CSIC), Campus Universitario de Espinardo, 30100 Murcia, Spain Accepted 15 December 2006Abstract 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. r 2007 Elsevier Ltd. All rights reserved. Keywords: Carnation mottle virus; Carnation vein mottle virus; Carnation latent virus; Carnation etched ring virus; Dianthus caryophyllus; cv. Dixie; In situ hybridization; Immunohistochemistry; Shoot tip; Shoot apical meristem; Single and mixed viral infection1. Introduction The systemic infection of a plant depends on the capacity of a given virus to replicate in the initially infected cells, move to adjacent cells through the plasmodesmata and reach distal parts of the plant through the vasculature [1,2]. Although considerable progress has been made during recent few years to elucidate virus invasion patterns of plant organs and tissues, viral infection of the shoot tips have been less st