Archivio Journal of Plant Pathology

Abstract:

In summer 2008, symptoms resembling those of a virus disease, i.e. chlorotic veins, deformation of the leaves and fruits, albinism and browning, were observed in chile pepper (Capsicum annuum L.) fields at Yurécuaro (Michoacán, México). However, ELISA tests were negative for the viruses most commonly associated with this crop. Based on these results, and knowing that in the state of Sinaloa (México), Candidatus Liberibacter solanacearum (Ca.L.s.) was detected in chile plants showing shortened internodes, apical chlorosis and symptoms similar to those of “yellow psillid” in potato, it was thought that the symptoms of chile in Yurécuaro could be induced by this bacterium. In this study the etiology of the variegation of chile was determinated. Symptomatic plants were collected in the Yurécuaro region in order to detect in leaves and seeds the possible causal agent by PCR and transmission electron microscopy, and to transmit the pathogen by grafting, Bactericera cockerelli, and through seed. In leaf tissue and seed of affected plants, Ca L.s. was detected by PCR, using primers OA2 and OI2c. The bacterium was also detected in thin sectioned phloem cells of affected leaves. Disease symptoms were reproduced in plants grafted with infected tissue and in those exposed to adults of B. cockerelli collected from diseased plants. The evidence obtained indicates that the variegation of chile pepper in Yurécuaro is induced by Ca.L.s.