GENETIC VARIABILITY OF PRSV-p ISOLATES FROM PAPAYO IN THE CENTRAL ZONE OF THE STATE OF VERACRUZ, MEXICO

Background: The Potyvirus Papaya ringspot virus type P (PRSV-p) causes the papaya (Carica papaya L.) ringspot disease, which causes damage to the plantations of this crop. In regions where there is movement of plant material and continuous production processes, there is greater genetic variability of this virus; such is the case of the State of Veracruz, Mexico, one of the main papaya producers in the country. Objective: To analyze the genetic variability of isolates of PRSV-p, present in commercial papaya plantations in the central zone of the State of Veracruz. Methodology: Leaves with differential symptoms of the disease were collected. The capsid protein (CP) coding region was amplified by RT-PCR to confirm the identity of the virus. The sequences obtained were analyzed, aligned and a phylogenetic tree was obtained. Results: The presence of PRSV-p was confirmed by RT-PCR. Through sequence analysis, high diversity was observed in the first 50 amino acids encoded in the N-terminal region of CP. In the phylogenetic tree, three viral genetic groups were obtained. The largest conserved sites of interest (even the WCIEN box and QMKAAA) were found near the C-terminal region of the CP. 100% homology was observed in the central and C-terminal region of the Ver75Co isolate, with respect to the consensus sequence. Implications: The results show the genetic diversity of the virus in the central zone of the state of Veracruz, which will allow genetic modifications to improve resistance in papaya plants. Conclusions: There is genetic variability of PRSV-p in Veracruz, there are conserved sites of interest (WCIEN and QMKAAA) and changes in the N-terminal region, which includes the EK repetitive region and the DAG codon. These changes may be a genetic characteristic of the virus for adaptation. The Ver75Co isolate may be the point of change that gives rise to the other isolates of this work. The phylogenetic tree shows a single genetic group of the virus, which is distributed in three different clades.