RESUMEN
The cultivation of pineapple (Ananas comosus) is threatened worldwide by mealybug wilt disease of pineapple (MWP), whose etiology is not yet fully elucidated. In this study, we characterized pineapple mealybug wilt-associated ampeloviruses (PMWaVs, family Closteroviridae) from a diseased pineapple plant collected from Reunion Island, using a high-throughput sequencing approach combining Illumina short reads and Nanopore long reads. Reads co-assembly resulted in complete or near-complete genomes for six distinct ampeloviruses, including the first complete genome of pineapple mealybug wilt-associated virus 5 (PMWaV5) and that of a new species tentatively named pineapple mealybug wilt-associated virus 7 (PMWaV7). Short reads data provided high genome coverage and sequencing depths for all six viral genomes, contrary to long reads data. The 5' and 3' ends of the genome for most of the six ampeloviruses could be recovered from long reads, providing an alternative to RACE-PCRs. Phylogenetic analyses did not unveil any geographic structuring of the diversity of PMWaV1, PMWaV2 and PMWaV3 isolates, supporting the current hypothesis that PMWaVs were mainly spread by human activity and vegetative propagation.
Asunto(s)
Ananas , Closteroviridae , Genoma Viral , Secuenciación de Nucleótidos de Alto Rendimiento , Filogenia , Enfermedades de las Plantas , Ananas/virología , Enfermedades de las Plantas/virología , Closteroviridae/genética , Closteroviridae/clasificación , Closteroviridae/aislamiento & purificación , Reunión , ARN Viral/genéticaRESUMEN
The increase in human-mediated introduction of plant species to new regions has resulted in a rise of invasive exotic plant species (IEPS) that has had significant effects on biodiversity and ecosystem processes. One commonly accepted mechanism of invasions is that proposed by the enemy release hypothesis (ERH), which states that IEPS free from their native herbivores and natural enemies in new environments can outcompete indigenous species and become invasive. We here propose the virome release hypothesis (VRH) as a virus-centered variant of the conventional ERH that is only focused on enemies. The VRH predicts that vertically transmitted plant-associated viruses (PAV, encompassing phytoviruses and mycoviruses) should be co-introduced during the dissemination of the IEPS, while horizontally transmitted PAV of IEPS should be left behind or should not be locally transmitted in the introduced area due to a maladaptation of local vectors. To document the VRH, virome richness and composition as well as PAV prevalence, co-infection, host range, and transmission modes were compared between indigenous plant species and an invasive grass, cane bluestem (Bothriochloa barbinodis), in both its introduced range (southern France) and one area of its native range (Sonoran Desert, Arizona, USA). Contrary to the VRH, we show that invasive populations of B. barbinodis in France were not associated with a lower PAV prevalence or richness than native populations of B. barbinodis from the USA. However, comparison of virome compositions and network analyses further revealed more diverse and complex plant-virus interactions in the French ecosystem, with a significant richness of mycoviruses. Setting mycoviruses apart, only one putatively vertically transmitted phytovirus (belonging to the Amalgaviridae family) and one putatively horizontally transmitted phytovirus (belonging to the Geminiviridae family) were identified from B. barbinodis plants in the introduced area. Collectively, these characteristics of the B. barbinodis-associated PAV community in southern France suggest that a virome release phase may have immediately followed the introduction of B. barbinodis to France in the 1960s or 1970s, and that, since then, the invasive populations of this IEPS have already transitioned out of this virome release phase, and have started interacting with several local mycoviruses and a few local plant viruses.
RESUMEN
Se realiza un estudio de quince años (1990-2005) en 90 pacientes susceptibles de ser controlados y seguidos, de un total de 156 pacientes operados con el diagnóstico de cáncer laríngeo, en el servicio de Otorrinolaringología del Hospital General Docente Dr. Agostinho Neto, de Guantánamo. Las variables estudiadas son: edad, localización del tumor, etapa clínica, tipo de operación realizada y sobrevida durante el período de estudio, luego de la intervención quirúrgica. Los resultados del tratamiento se evalúan según la sobrevida lograda. El mayor número de pacientes se localizó en los grupos de edades de 71 y más años y, en general, entre la quinta y séptimas décadas de vida; del total de pacientes, 55, se encuentran vivos y 35 fallecidos. La localización gloto-subglótica y glótica aportaron el mayor número de pacientes. El proceder quirúrgico más empleado fue la laringectomía total, seguida de la laringectomía con vaciamiento radical de cuello y la laringectomía parcial con un número menor de casos. El diagnóstico se realiza predominantemente en la etapa clínica I, con 40 pacientes de los que sobreviven, 28, y la etapa III con, 32, de los cuales sobreviven, 19. Es notoria la supervivencia de 4 pacientes a los 13, 2, 4.5 y 6 años de evolución, pues en los demás el comportamiento de los pacientes vivos fue bastante similar (AU)