Potato yellow vein virus (PYVV), (familia Closteroviridae, género Crinivirus) es un virus re-emergente para los países Andinos. Se ha reportado baja variación del gen CP de PYVV entre aislados, pero no hay reportes de variación intra aislado. Se estudió tanto la variación inter como intra aislado del CP de una población de PYVV. Muestras de 216 plantas de papa sintomáticas (115 Solanum tuberosum subsp. andigena (STA), 100 Solanum phureja (SPH) y 1 Solanum chaucha (SCH)) se colectaron en 5 departamentos de Colombia. Los aislados se amplificaron por RT-PCR y los amplicones se analizaron por polimorfismo conformacional de cadena sencilla (SSCP). Se observaron seis patrones de migración de SSCP distintos (A a F) con diferentes complejidades. El patrón A fue detectado en cinco departamentos en 66% de los aislados y el E solo en el departamento de Cundinamarca con una frecuencia de 0,09%. Los patrones B, C, D y F se encontraron en proporciones similares entre 13% a 5,6%, y estuvieron presentes en los cinco departamentos. La homología de nucleótidos del 75% de la secuencia del gen CP fue mayor del 99% y la tasa dN/dS (cambios no sinónimos/ cambios sinónimos) fue de 0,002. Amplicones del gen completo de CP de ocho aislados que representaban los seis patrones de SSCP se clonaron y un análisis SSCP mostró que todos tenían más de una variante. El análisis de secuencias de 35 clones confirmó la variabilidad intra aislado de PYVV. La existencia de varias variantes en un solo aislado de campo se demostró y se sugiere selección negativa de cambios de aminoácidos en al CP.

Potato yellow vein virus (PYVV), (family Closteroviridae, genus Crinivirus) is a re-emergent virus in Andean countries. Low inter-isolate variation has been reported for PYVV CP gene, but there are no reports for intra-isolate variation. Inter- and intra-isolate variability in CP from a population of PYVV was studied. Samples of 216 symptomatic potato plants (115 Solanum tuberosum subsp. andigena (STA), 100 Solanum phureja (SPH) and 1 Solanum chaucha (SCH)) were collected in five Colombian departments. Viral isolates were amplified by RT-PCR and the amplicons were analyzed by single-strand conformation polymorphism (SSCP). Six different migration SSCP patterns (A to F) with different complexities were observed among the population. Pattern A was detected in the five departments in 66% of the isolates. Pattern E was found only in the department of Cundinamarca with a frequency of 0.09%. Patterns B, C, D and F were found in similar proportions of from 13% to 5.6% and were present in the five departments. Homology at the nucleotide level of 75% of the sequence of the CP gene was greater than 99% and the dN/dS ratio (no-synonymous/synonymous changes) was 0.002. Amplicons of the whole CP gene of eight selected isolates representing the six SSCP patterns were cloned and the SSCP analysis showed that, in all cases, more than one variant was present. The sequence analysis of the 35 clones confirmed intra-isolate variability of PYVV. The existence of several variants in a single field isolate was demonstrated and negative selection against amino acid changes of the CP was suggested.

Potato yellow vein virus (PYVV) expresses yellowing symptoms on plants and it is transmitted by the whitefly vector Trialeurodes vaporariorum Westwood. No molecular viral detection from the vector extracts has been reported to date. The objectives of this study were I) amplification of the PYVV major coat protein (CP) gene from viruliferous vector extracts by RT-PCR using specific primers, II) cloning and III) sequencing and sequences analysis. Some Colombian Solanum phureja (Jus et Buk) field potato plants expressing yellowing symptoms and confirmed PYVV positive by RT-PCR were used as virus donor plants for feeding whiteflies. Viruliferous vectors were obtained by depositing aviruliferous whiteflies on symptomatic leaves and kept in a muslin cloth-covered glass flask for 48 h. A kit SV for total RNA Isolation System (Promega®) was used for extracting the viral RNA from one viruliferous whitefly and from pools of viruliferous vectors (2, 5, 10, 15 and 20 individuals); CP gene amplicons of about 765bp were cloned and sequenced to confirm the PYVV genome. Blast alignment established more than 99% similarity between CP gene amplified from vector extracts and several GenBank reported PYVV CP genes from Colombian and Peruvian isolates.This study presents information concerning the molecular detection of PYVV in its natural vector for the first time by using a very simple viral acquisition technique for obtaining viruliferous vectors that could be of interest for future studies concerning virus and vector gene characterization, plant-virus and vector interaction and/or epidemiological studies.

El Potato yellow vein virus (PYVV) produce síntomas de amarillamiento en las nervaduras de la hoja de papa, y es transmitido por el vector natural Trialeurodes vaporariorum Westwood (mosca blanca). Hasta la fecha no se ha detectado molecularmente PYVV en extractos de moscas virulíferas. Los objetivos de este estudio fueron I) amplificar el gen de la proteína mayor de la cápside (CP) de PYVV a partir de extractos del vector, utilizando RT-PCR con cebadores específicos, II) clonar los amplicones y III) secuenciar y analizar las secuencias. Se utilizaron como donadoras de virus, las plantas de papa Solanum phureja (Jus et Buk), colectadas en campo con síntomas de amarillamiento y confirmadas positivas para PYVV por RT-PCR. Se depositaron moscas aviruliferas en hojas sintomáticas cubiertas con tela de muselina, para la adquisición de PYVV durante 48 h. Para la extracción de RNA viral se empleó el kit SV total RNA Isolation System (Promega®), utilizando una mosca o grupos (2, 5, 10, 15 y 20 individuos). Los amplicones obtenidos de CP, aproximadamente 765 pb se clonaron y secuenciaron. Las secuencias obtenidas se alinearon con la herramienta BLAST; se establecieron similitudes del 99% entre el amplicón derivado del vector y secuencias del gen CP de aislados de PYVV colombianos y peruanos.

El Potato yellow vein virus (PYVV) es un Crinivirus de genoma RNA tripartita, agente causal de la enfermedad del amarillamiento de las nervaduras de la papa reportada desde 1950 en Colombia con reducción de producción hasta 50%. La coinfección entre virus en un mismo hospedero es común en la naturaleza y se asocia con cambios en acumulación viral y en la expresión de síntomas. Hasta el momento no se ha reportado coinfección entre PYVV y otros virus en papa. En este estudio se colectaron en Cundinamarca-Colombia ocho plantas con síntomas de PYVV: cuatro Solanum tuberosum Grupo Phureja (P) y cuatro del Grupo Andigena (A). Utilizando secuenciamiento de alto rendimiento (NGS) en los aislamientos se detectó infección mixta de PYVV con potyvirus que se reconfirmó con RT-PCR. Estudios preliminares en una muestra mayor de campo confirmaron que PYVV y PVY coinfectan papa con 21% de prevalencia para el grupo P y 23% para el grupo A. Este es el primer reporte de coinfección de PYVV y potyvirus en Colombia. Teniendo en cuenta que los potyvirus pueden incrementar la severidad de síntomas y/o reducir el rendimiento en infecciones mixtas, los resultados presentados pueden ser relevantes para el diagnóstico de enfermedades virales, programas de propagación y de certificación de semillas.

The Potato yellow vein virus (PYVV), a Crinivirus with an RNA tripartite genome, is the causal agent of the potato yellow vein disease, reported in Colombian since 1950, with yield reductions of up to 50%. Co-infection of two or more viruses is common in nature and can be associated with differences in virus accumulation and symptom expression. No evidence of mixed infection between PYVV and other viruses has been reported. In this study, eight plants showing yellowing PYVV symptoms: four Solanum tuberosum Group Phureja (P) and four Group Andigena (A), were collected in Cundinamarca, Colombia to detect mixed infection in the isolates using next generation sequencing (NGS). The Potato virus Y (PVY) complete genome (similar to N strain) and the Potato virus V (PVV) partial genomes were detected using NGS and re-confirmed by RT-PCR. Preliminary field screening in a large sample showed that PYVV and PVY co-infect potato plants with a prevalence of 21% within the P group and 23% within the A group. This is the first report of co-infection of PYVV and potyvirus in Colombia and with the use of NGS. Considering that potyviruses enhance symptom severity and/or yield reductions in mixed infections, our results may be relevant for disease diagnosis, breeding programs and tuber certification.

Potato yellow vein virus (PYVV) is currently one of the most important viruses that infects potatoes in Colombia and other Andean countries, causing losses in the production of tubers ranging from 25% to 50%. This study analyzed the genetic variability of different viral isolates collected in the department of Nariño, Colombia, through bioinformatics analysis of the sequences of three genes encoding the capsid protein (CP), the heat-shock protein 70 (Hsp70) and the minor capsid protein (CPm). We found that CPm is the gene that shows greater diversity, with higher values of nucleotide substitution and evidence of recombination. Based on an analysis of the haplotype map using nucleotide sequences of the CPm, we propose a model of putative recombination in this genomic region. The non-recombinant segments are supported by the results of the program GARD (Genetic Algorithm for Recombination Detection), phylogenetic trees and the paired values of genetic distances of each non-recombinant segments. The model clearly shows that the amino region of the CPm is prone to recombination. To our knowledge, this is the first report of genetic recombination as an evolutionary strategy in the CPm of PYVV.

En este trabajo se estimó la estructura poblacional y variación genética del virus del amarillamiento de las venas de la papa (PYVV) infectando cultivos en Colombia por medio del análisis de 69 secuencias nucleotídicas y aminoácidos deducidos de la proteína mayor de la cápside (CP) reportados en el banco de genes (GenBank). Los aislamientos de PYVV fueron obtenidos de los hospederos Solanum tuberosum (ST ) y Solanum phureja (SP) en diferentes regiones de Colombia, predominantemente los departamentos de Cundinamarca, Antioquia y Nariño localizados en la región Central y Sur Oeste del país respectivamente. El análisis bioinformático reveló que a pesar de la amplia distribución geográfica de los hospederos y diferentes años de colecta, PYVV mantiene un similitud genética entre 97,1 y 100,0% indicando una gran estabilidad genética espacial y temporal en la CP. En este estudio no se detectaron eventos de recombinación, pero se presenta evidencia por primera vez de que esta proteína podría estar bajo selección darwiniana diversificadora

The population structure and genetic variation of Potato yellow vein virus (PYVV) were estimated by analysis of the nucleotide and deduced amino acid sequence of the coat protein of 69 isolates, reported in GenBank, from Solanum tuberosum (ST ) and Solanum phureja (SP) hosts from different regions; predominantly Cundinamarca, Antioquia and Nariño, located in central and southwestern Colombia. Bioinformatics analysis revealed that despite the wide geographic distribution of different hosts and different collecting years, PYVV maintains a genetic similarity between 97.1 to 100.0%, indicating high spatial and temporal genetic stability of the major coat protein. No recombination events were found, but evidence was seen for the first time that this protein could be undergoing Darwinian diversifying selection