Journal of Plant Pathology (2005) 87, 280-281

M.E. Rodio, A. De Stradis, S. Delgado, R. Flores and F. Di Serio (2005)
Interactions between Peach latent mosaic viroid variants causing peach calico disease and the natural host: cellular and molecular studies
Journal of Plant Pathology 87 (4), 280-281
XII Meeting, Italian Society for Plant Pathology, Reggio Calabria, 29/9 - 1/10, 2005
Abstract: Peach calico, a disease characterized by a severe chlorosis (albinism) of leaves, stems and fruits, is caused by Peach latent mosaic viroid (PLMVd) variants containing a molecular determinant located in a 12-13 nt insertion that adopts a hairpin conformation capped by a U-rich loop. Histological, cytological and molecular alterations of peach leaves expressing PC symptoms are described. Albino leaf areas lack a differentiated mesophyll cell layer and contain cells with altered proplastids instead of fully developed chloroplasts. Because PLMVd replicates actively in PC symptomatic areas, our findings suggest that PLMVd variants inducing PC block an early step of chloroplast biogenesis impairing plastid-to-nucleus signaling pathways involved in leaf differentiation, a condition resembling that of some albino mutants. The discovery that PLMVd invades the shoot apex, the site of chloroplast biogenesis, and that proplastids from the apex of PCexpressing shoots are structurally altered, strongly support this hypothesis. Because the discolored areas had reduced accumulation of chloroplast ribosomal RNAs and plastid-encoded proteins, the inhibition of chloroplast differentiation could result from impaired protein translation in proplastids caused by the viroid. An important implication of these findings is that all host proteins mediating PLMVd chloroplastic replication must be nucleus-encoded.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Francesco Di Serio, Angelo De Stradis

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution
molecular biology - genes

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Peach latent mosaic viroid