Interactions between peach latent mosaic viroid variants causing peach calico disease and the natural host: cellular and molecular studies.

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.