RESUMO
Bemisia tabaci is a species complex that causes damage to its broad range of plant hosts through serious feeding. It transmits plant viruses of different groups to important agricultural crops. Some important cash crops of Pakistan are sugar cane, rice, tobacco and seed oil. It shows high genetic variability and is differentiated as races or biotypes. Biotypes are, biotype Q, biotype B, biotype B2, biotype M, biotype L, biotype A, biotype H, biotype C, biotype K, biotype N, biotype R, biotype E, biotype P, biotype J, biotype S, biotype AN. Although the current report based on the Bayesian study of mitochondrial cytohrome oxidase gene1 (CO1) DNA sequences has classified the different populations of whiteflies into twelve genetic groups which are Mediterranean, Sub-Saharan Africa silverleafing, Indian Ocean, Asia II, Asia I, Australia, New World, Italy, China, Sub-Saharan Africa non-silverleafing, Mediterranean/Asia Minor/Africa and Uganda sweet potato. Begomoviruses is largest group of viruses transmitted by B. tabaci and cause major diseases of crops such as tomato and chili leaf curl disease, cassava mosaic disease; yellow mosaic disease of legumes and cotton leaf curl disease. The main objective of current study is to inculpate knowledge regarding genetic diversity of whitefly in cotton fields across Pakistan via analysis of partial DNA sequence of mitochondrial gene Cytochrom Oxidase I (mtCO1).
Bemisia tabaci é um complexo de espécies que causa danos a uma ampla gama de hospedeiros vegetais por meio de alimentação séria. Ele transmite vírus de plantas de diferentes grupos para importantes safras agrícolas. Algumas safras comerciais importantes do Paquistão são cana-de-açúcar, arroz, tabaco e óleo de semente. Apresenta alta variabilidade genética e é diferenciado em raças ou biótipos. Os biótipos são: biótipo Q, biótipo B, biótipo B2, biótipo M, biótipo L, biótipo A, biótipo H, biótipo C, biótipo K, biótipo N, biótipo R, biótipo E, biótipo P, biótipo J, biótipo S, biótipo AN . Embora o relatório atual baseado no estudo bayesiano das sequências de DNA do gene 1 da oxidase do citocromo mitocondrial (CO1) tenha classificado as diferentes populações de moscas-brancas em doze grupos genéticos, que são Mediterrâneo, África Subsaariana com folha de prata, Oceano Índico, Ásia II, Ásia I, Austrália, Novo Mundo, Itália, China, África Subsaariana sem folha prateada, Batata-doce Mediterrâneo / Ásia Menor / África e Uganda. Os begomovírus são o maior grupo de vírus transmitidos por B. tabaci e causam as principais doenças de culturas, como a doença do cacho do tomate e da pimenta-malagueta, doença do mosaico da mandioca, doença do mosaico amarelo de leguminosas e doença do enrolamento da folha do algodão. O principal objetivo do presente estudo é inculpar conhecimento sobre a diversidade genética da mosca-branca em campos de algodão em todo o Paquistão por meio da análise da sequência parcial de DNA do gene mitocondrial Citocromo Oxidase I (mtCO1).
Assuntos
Variação Genética , Genes Mitocondriais , Begomovirus , Pragas da AgriculturaAssuntos
Begomovirus/genética , Solanum lycopersicum/virologia , Doenças das Plantas/virologia , Plantas Geneticamente Modificadas/virologia , Interferência de RNA , Vírus Satélites/genética , Begomovirus/fisiologia , Solanum lycopersicum/genética , Solanum lycopersicum/imunologia , Omã , Doenças das Plantas/genética , Doenças das Plantas/imunologia , Doenças das Plantas/prevenção & controle , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/imunologia , RNA de Cadeia Dupla/genética , RNA de Cadeia Dupla/metabolismo , RNA Viral/genética , RNA Viral/metabolismo , Vírus Satélites/fisiologiaRESUMO
La transmisión experimental de Begomovirus es problemática. La mayoría de estos virus se pueden transmitir de planta a planta por su vector biológico, Bemisia tabaci. Las inoculaciones experimentales con mosca blanca son problemáticas debido a sus hábitos de alimentación, requerimiento de una planta viva infectada e instalaciones de contención para el vector. Por su parte la inoculación mecánica de Begomovirus es posible, pero generalmente a tasas bajas y no en todos los casos. Por esta razón el bombardeo de partículas (biobalística) de DNA viral como una estrategia de inoculación fue desarrollada. La posibilidad de utilizar el dispositivo de mano Helios Gen Gun System (Biorad®), un equipo de biobalística, para la transmisión de un Begomovirus bipartita a plantas de tomate y tabaco fue ensayado y optimizado. Los parámetros evaluados fueron: número de disparos (1-2), presión de helio (220 y 320 psi) y diámetro de las partículas de oro (0.6 y 1.6µm). Los síntomas característicos de la enfermedad viral (clorosis, mosaico y deformación de la hoja) aparecieron 3 semanas después del bombardeo en las hojas jóvenes no inoculadas. La replicación del DNA viral en las plantas se confirmó por Reacción en cadena de la polimerasa. Plantas infectadas en un 100 se obtuvieron cuando en el bombardeo se emplearon partículas de oro de 1.6 µm recubiertas con DNA viral a una presión de 320psi. A nuestro entender este es el primer reporte en Colombia de la inoculación directa de plantas de tomate y tabaco con un Begomovirus bipartita usando un dispositivo portátil de biobalística.
Experimental transmission of Begomovirus is problematic. Most Begomoviruses can be transmitted readily from plant to plant by the whitefly vector, but this also requires a live infected plant and extensive facilities to maintain the insect. Whitefly inoculations can also be problematic because of their preferential feeding habits on certain plants. Mechanical inoculation of Begomovirus is possible but generally at low rates and for others not at all. For this reason particle bombardment (biolistic) of DNA viral as an inoculum was developed. The possibility of using the Helios Gen Gun System (Biorad®), a biolistic hand-held device, for transmitting Begomovirus bipartite to tomato and tobacco plants was assayed and optimized. Biolistic inoculation was carried out with the hand held device at 220 or 320 psi, applying 1 or 2 shots /plant and using gold particles of 0.6 or 1.6µm in size. Characteristic symptoms of viral disease (chlorosis, mosaic and leaf deformation) appeared 3 weeks post-inoculation in the newly developing leaves. Replication of the viral DNA in plants was confirmed by Polymerase Chain Reaction. All bombarded plants became infected when biolistic inoculation was carried out with the hand held device at 320psi and using 1.6 µm gold particles in size. To our knowledge this is the first report in Colombia of successful direct inoculation of tomato and tobacco plants with Begomovirus bipartite geminivirus using a biolistic hand-held device.
Assuntos
Begomovirus , Solanum lycopersicum , Geminiviridae/isolamento & purificação , Geminiviridae/classificação , Geminiviridae/crescimento & desenvolvimento , Geminiviridae , Geminiviridae/efeitos da radiação , Geminiviridae/enzimologia , Geminiviridae/fisiologia , Geminiviridae/genética , Geminiviridae/imunologia , Geminiviridae/metabolismo , Geminiviridae/patogenicidade , Geminiviridae/química , Otimização de Processos/classificação , Otimização de Processos/efeitos adversos , Otimização de Processos/estatística & dados numéricos , Otimização de Processos/métodos , NicotianaRESUMO
Las enfermedades causadas por los begomovirus, (Familia Geminiviridae) constituyen una serie limitante para la producción del tomate en Colombia. Sin embargo, la caracterización de estos virus no ha sido realizada al momento. Aquí presentamos los resultados de un muestreo a nivel nacional que buscaba conocer la distribución y diversidad genética de los geminivirus que están afectando el cultivo de tomate en Colombia. Los virus fueron detectados mediante PCR, empleando primer universales específicos para el género Begomovirus. Los fragmentos amplificados por PCR fueron sometidos a un análisis tipo RFLP cuyos resultados evidenciaron presencia de infecciones mixtas e individuales de geminivirus en la mayoría de las muestras recolectadas en campo. Los fragmentos amplificados por PCR fueron clonados y secuenciados. El analísis de secuencia y filogenético mostró que los aislados begomovirales colombianos eran gemininivirus bipartitas típicos del Hemisferio Occidental y que algunos eran variantes de PYMV y otros de ToTEV. Mediante el análisis de los elementos cis-regulatorios (iterones) presentes en el promotor del gen de la proteína asociada a replicación (Rep) de los begomovirus aislados es posible postular eventos de pseudorecombinacién que podrían suceder entre ellos durante la ocurrencia de infecciones mixtas en tomate.
Diseased caused by begomoviruses (Family Geminiviridae) constitute a serious constraint to tomato production in Colombia. However characterization of these new viruses had not been carried out so far. Here we report a large scale survey on the distribution and genetic diversity of tomato infecting geminiviruses which are affecting mayor growing area of this crop in the country. Viruses were detected by PCR using universal primers for members of genus Begomovirus. The RFLP analysis of PCR-amplified fragments showed individual and mixed infections of several geminiviruses in many of the samples. PCR-amplified fragments were cloned and sequenced. Based on sequence comparations and phylogenetic analysis, the Colombian geminivirus isolates were new world bipartite geminiviruses showing close relationship with PYMV and ToVEV. By means of bioinformatic analysis of cis-acting elements (iterons) involved in DNA replication of rep gene of Colombian geminivirus isolates was possible to postulate possible pseudorecombinación events that could occur between them but also confirm the occurrence of mixed infections.
Assuntos
Begomovirus , Geminiviridae , Colômbia , SolanumRESUMO
En la actualidad, los Begomovirus (Familia Geminiviridae) se han convertido en la mayor amenaza para los cultivos de interés agrícola ubicados en las zonas tropicales y templadas del planeta. Estos virus son transmitidos por la mosca blanca Bemisia tabaci, la cual en los últimos años en Colombia ha tenido un aumento significativo en sus poblaciones y se ha asociado con la aparición de síntomas virales en cultivos de tomate. Muestras de tomate con síntomas virales típicos fueron recolectadas en las cinco principales zonas productoras de esta solanácea en el país. Los Begomovirus fueron detectados por medio de la técnica de hibridación de ácidos nucleicos tipo Dot blot así como por medio de la reacción en cadena de la polimerasa (PCR) en todas las muestras colectadas. Con la excepción de un reporte previo en el Valle del Cauca, este es el primer reporte de Begomovirus afectando cultivos de tomate en los departamentos de Antioquia, Santander, Boyacá y Cundinamarca. Asimismo, es la primera vez que se informa sobre Begomovirus que afectan cultivos de tomate localizados por encima de 1500 msnm en Colombia.
The begomoviruses (Family Geminiviridae) have recently emerged as samples with typical Begomovirus symptoms were collected in five different departments, comprising the mayor tomato growing areas of the country. Begomovirus were detected by Polymerase Chain Reaction (PCR) or Dot Blot Hybridization in all tomato samples collected in whole tomato growing areas of the country. With exception for Valle del Cauca, this is the first report of tomato-infecting Begomovirus in Antioquia, Santander, Boyacá and Cundinamarca departments. Also this is the first report of tomato-infecting Begomovirus crops located above 1500 masl in Colombia.
Assuntos
Begomovirus/isolamento & purificação , Begomovirus/crescimento & desenvolvimento , Begomovirus , Begomovirus/enzimologia , Begomovirus/fisiologia , Begomovirus/genética , Begomovirus/imunologia , Begomovirus/metabolismo , Begomovirus/patogenicidade , Begomovirus/química , Reação em Cadeia da Polimerase/classificação , Reação em Cadeia da Polimerase/métodos , Reação em Cadeia da PolimeraseRESUMO
The biological transmission of Tomato Venezuela virus (ToVEV) by biotype B of the whitefly species Bemisia tabaci (Gennadius) increased (21.7-95.0 percent), and the time for symptom expression decreased (16-12.6 days) as the number of viruliferous whiteflies allowed access for inoculation to susceptible tomato plants increased from 1 to 20 adults/plant. When acquired only as a nymph, adults of this biotype transmitted the virus to 88.3 percent of susceptible tomato plants, using 15 viruliferous individuals per test plant, corroborating the circulative nature of the transmission. Disease incidence further increased (up to 100 percent) when the individuals were allowed to feed again on a virusinfected plant as adults. Leaf area, plant height and dry matter were significantly affected in ToVEV infected tomato plants.
Assuntos
Animais , Begomovirus , Hemípteros/virologia , Solanum lycopersicum/virologia , Doenças das Plantas/virologia , VenezuelaRESUMO
Begomoviruses are single-stranded DNA viruses and cause severe diseases in major crop plants worldwide. Based on current genome sequence analyses, we found that synonymous codon usage variations in the protein-coding genes of begomoviruses are mainly influenced by mutation bias. Base composition analysis suggested that the codon usage bias of AV1 and BV1 genes is significant and their expressions are high. Fourteen codons were determined as translational optimal ones according to the comparison of codon usage patterns between highly and lowly expressed genes. Interestingly the codon usages between begomoviruses from the Old and the New Worlds are apparently different, which supports the idea that the bipartite begomoviruses of the New World might originate from bipartite ones of the Old World, whereas the latter evolve from the Old World monopartite begomoviruses.