Occurrence, Distribution, and Population Structure of Schlumbergera Virus X in Dragon Fruit in Ecuador

Resumen

The occurrence of Schlumbergera virus X (SchVX) in commercial dragon fruit fields in three provinces of Ecuador has been identified in this study. The virus was found in symptomatic and asymptomatic cladodes of the two major species (<i>Hylocereus undatus</i> and <i>H</i>. <i>megalanthus</i>) cultivated in the country. Symptoms in <i>H. undatus</i> included irregular and ring-shaped chlorotic spots that coalesce into large chlorotic patches along the cladodes, whereas small chlorotic spot symptoms on the cladodes were observed in <i>H. megalanthus</i>. Phylogenetic inferences based on 27 partial nucleotide sequences of the RNA-dependent RNA polymerase (RdRp) and three whole genome comparisons showed that Ecuadorean isolates from <i>H. undatus</i> and <i>H. megalanthus</i> share a most recent ancestor with isolates from Spain and Portugal. In addition, an SchVX isolate with a distinct genomic lineage was found in symptomatic <i>H. polyrhizus</i> plants from a single location, suggesting two independent virus introductions into the country.