Phytopathology and cultural behaviors: putative introduction of Chaya-strain of Cassava common mosaic virus to Costa Rica

Abstract

Leaves of the shrub chaya (Cnidoscolus aconitifolius), spinach tree or ‘chicasquil’ (in Costa Rica), are consumed in the Mesoamerican culinary tradition, having its origin in South Mexico and Guatemala. The objective of this work was to verify the viral nature of the observed in a chaya plant disease and to identify the species of the virus. Plant virus detection and identification was achieved by TEM, RT-PCR using degenerated primers to potexviruses, and sequencing. Pathogenicity tests were done by mechanical inoculation using chaya symptomatic tissue, on Nicotiana benthamiana and chaya plants. We report CsCMV detection in a chaya plant in Costa Rica with mosaic symptoms. Pathogenicity and association of virus and symptoms were demonstrated by mechanical inoculation in Nicotiana benthamiana and chaya plants. We hypothesize this infection corresponds to a recent introduction and discussed how cultural traditions impact the distribution of plant viruses. The findings confirm the presence of a CsCMV-related virus, previously unreported for Costa Rica, in Cnidoscolus aconitifolius. The results herein highlighted the need to study its distribution and diversity throughout Latin America.