Resumo

TORRE-ALMARAZ, Rodolfo De La; SALAZAR-SEGURA, Mario  e  RUIZ-MEDRANO, Roberto. Occurrence of a tobamovirus associated with yellow ringspots in prickly pear cactus in Mexico. Agrociencia [online]. 2007, vol.41, n.7, pp.763-773. ISSN 2521-9766.

A virus was detected in fruit prickly pear cladodes cultivated in the region of San Martín de las Pirámides, State of Mexico, causing yellow ringspots. In severe attacks the affected cladodes develop chlorosis and wilting. The virus was transmitted mechanically to species of indicator host plants in which localized chlorotic lesions, later becoming necrotic, were caused on inoculated leaves; only Nicotiana tabacum L. var. White Burley and Capsicum annuum L. also developed tenuous mosaic on non-inoculated leaves. Symptom development on alternate hosts was slow, but accelerated at temperatures above 30 °C in a greenhouse. Electrophoretic analysis and treatment with double stranded RNA nuclease showed that the virus isolated from prickly pear plants has a single stranded RNA genome, while macerated tissue analysis of the indicator host species with mosaic under an electronic microscope showed rigid bar-shaped particles 300-350 mm long. Besides, an RT-PCR assay confirmed that the virus is a species of the Tobamovirus group. The biological characteristics of this virus indicate that it is a non-severe variant related to the species Opuntia Sammons’ virus.

Palavras-chave : Opuntia amyclaea; virus.

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