Species within the Bemisia tabaci (Hemiptera: Aleyrodidae) Complex in Soybean and Bean Crops in Argentina

The White fly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex that contains some of the most damaging pests in tropical and subtropical regions. Recent studies suggested that this complex is composed of at least 24 distinct species. We use the approach from these studies to consider the identity of B. tabaci in Argentina. Previous studies have suggested the presence of a B. tabaci presumably indigenous to the Americas and referred to as the BR biotype in Argentina. We placed the entity referred to as the BR biotype within the B. tabaci cryptic species complex using whiteflies collected in soybean and bean crops in northern and central Argentina. The whiteflies were assigned using the mitochondrial cytochrome oxidase (mtCOI) gene. Four unknown haplotypes plus two Argentina sequences from GenBank formed a cluster that was basal to the rest of theNewWorld sequences. These sequences diverged from the consensus sequence across the range of 3.6 to 4.3%. Applying the species assignment rules of recent studies suggests that the individuals from Argentina form a separate species. A unknown haplotype fell within the New World putative species and formed a distinct cluster with haplotypes from Panama. These results suggest that Argentina has two indigenous species belonging to the B. tabaci cryptic species complex. Rather tan using mtCOI sequencing for all B. tabaci collected, a simple random amplifed polymorphic DNApolymerase chain reaction diagnostic was used and tested along with previously published primers designed to work specially with the BR biotype from Brazil. These primers were either unable to distinguish between the two indigenous members of the complex in Argentina or indicated a difference when none was evident on the basis of mtCOI sequence comparison.Fil: Alemandri, V.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: De Barro, P.. No especifíca;Fil: Bejerman, N.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: Argüello Caro, Evangelina Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Dumón, A. D.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: Mattio, Maria Fernanda. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Rodríguez, S. M.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; ArgentinaFil: Truol G.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Fitopatología y Fisiología Vegetal; Argentin

Identification and biological characterization of Barley yellow striate mosaic virus (BYSMV): a new wheat disease in Argentina

Wheat (Triticum aestivum L.) is the most important winter grain in Argentina. Its production is limited by several factors, including viral diseases. The aim of this study was to identify and characterize a recently detected disease of wheat crops in Argentina. Symptomatic plants were collected from different locations from the wheat production area, Miramar and Balcarce (Buenos Aires), Río Cuarto, Rosales and Marcos Juarez (Córdoba), Paraná (Entre Ríos) and General Pico (La Pampa). Samples were characterized by: electron microscopy (leaf-dip and ultrathin sections), serological tests (with antiserum reacting against different wheat viruses by DAS-ELISA and indirect ELISA), mechanical, seed and vector transmission assays, differential host range, and susceptibility of different wheat cultivars in natural infections. The results showed that this new disease is caused by Barley yellow striate mosaic virus (BYSMV) (Rhabdoviridae-Cytorhabdovirus), a widely distributed virus that can be transmitted to other crops such as barley, oat and triticale. This work representsthe first report of BYSMV in Argentina.El cultivo de trigo (Triticum aestivum L.), es el cereal de invierno de mayor importancia económica en Argentina. Su producción se halla limitada por diversos factores, entre ellos las enfermedades virales. El objetivo del presente trabajo fue identificar y caracterizar biológicamente una enfermedad viral detectada recientemente en el cultivo de trigo en Argentina, que ha presentado elevada incidencia en los últimos años. Para ello, se recolectaron plantas con síntomas en localidades de: Miramar y Balcarce (Buenos Aires), Río Cuarto, Rosales y Marcos Juárez (Córdoba), Paraná (Entre Ríos) y General Pico (La Pampa) de la región triguera Argentina. Las muestras fueron caracterizadas a través de: microscopia electrónica ("leaf-dip" y cortes ultrafinos), serología (con antisueros para diferentes virosis del trigo por DAS-ELISA y ELISA indirecto), transmisión mecánica, por semilla y por vectores (delfácidos), rango de hospedantes diferenciales y susceptibilidad diferencial de diferentes cultivares de trigo en infecciones naturales. Los resultados obtenidos evidenciaron que esta nueva enfermedad es causada por el Barley yellow striate mosaic virus (BYSMV) (Rhabdoviridae-Cytorhabdovirus), un virus ampliamente distribuido a nivel mundial y que representa un riesgo potencial para otros cultivos como cebada, avena y triticale. Este trabajo representa el primer reporte del BYSMV en Argentina.Fil: Dumón, Analía Delina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Unidad de Fitopatología y Modelización Agrícola - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Fitopatología y Modelización Agrícola; ArgentinaFil: Argüello Caro, Evangelina Beatriz. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Alemandri, María V.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Bainotti, Carlos Tomas. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Mattio, María F.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Rodríguez, Sandra M.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: del Vas, Mariana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Biotecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Truol, Graciela Ana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentin

African ancestry of New World, Bemisia tabaci-whitefly species

Bemisia tabaci whitefly species are some of the world’s most devastating agricultural pests and plant-virus disease vectors. Elucidation of the phylogenetic relationships in the group is the basis for understanding their evolution, biogeography, gene-functions and development of novel control technologies. We report here the discovery of five new Sub-Saharan Africa (SSA) B. tabaci putative species, using the partial mitochondrial cytochrome oxidase 1 gene: SSA9, SSA10, SSA11, SSA12 and SSA13. Two of them, SSA10 and SSA11 clustered with the New World species and shared 84.8‒86.5% sequence identities. SSA10 and SSA11 provide new evidence for a close evolutionary link between the Old and New World species. Re-analysis of the evolutionary history of B. tabaci species group indicates that the new African species (SSA10 and SSA11) diverged from the New World clade c. 25 million years ago. The new putative species enable us to: (i) re-evaluate current models of B. tabaci evolution, (ii) recognise increased diversity within this cryptic species group and (iii) re-estimate divergence dates in evolutionary time

An integrative approach to discovering cryptic species within the Bemisia tabaci whitefly species complex

Bemisia tabaci is a cryptic whitefly-species complex that includes some of the most damaging pests and plant-virus vectors of a diverse range of food and fibre crops worldwide. We combine experimental evidence of: (i) differences in reproductive compatibility, (ii) hybrid verification using a specific nuclear DNA marker and hybrid fertility confirmation and (iii) high-throughput sequencing-derived mitogenomes, to show that the “Mediterranean” (MED) B. tabaci comprises at least two distinct biological species; the globally invasive MED from the Mediterranean Basin and the “African silver-leafing” (ASL) from sub-Saharan Africa, which has no associated invasion records. We demonstrate that, contrary to its common name, the “ASL” does not induce squash silver-leafing symptoms and show that species delimitation based on the widely applied 3.5% partial mtCOI gene sequence divergence threshold produces discordant results, depending on the mtCOI region selected. Of the 292 published mtCOI sequences from MED/ASL groups, 158 (54%) are low quality and/or potential pseudogenes. We demonstrate fundamental deficiencies in delimiting cryptic B. tabaci species, based solely on partial sequences of a mitochondrial barcoding gene. We advocate an integrative approach to reveal the true species richness within cryptic species complexes, which is integral to the deployment of effective pest and disease management strategies

Climatic characterization of the wheat streak mosaic virus (WSMV) pathology system and its vector Aceria tosichella Keifer using a Geographical Information System (GIS)

Abstracts del XXIV ANNUAL SCIENTIFIC MEETING, celebrado del 8-10 de noviembre 2007, en Tafí del Valle, Tucumán, Argentina.In Argentina, the Wheat streak mosaic virus (WSMV) disease has been present since 2003, when it was detected for the first time in the districts of Marcos Juárez and Jesús María, province of Córdoba. Since then, the disease has been rapidly expanding. This study was undertaken for the purpose of characterizing through a geographical information system (GIS) the areas where the disease was detected up to the present. Data were used for 28 sites where virosis was detected during the 2003-2006 period. FloraMap 1.02 software was used to characterize the sites. Maximum and minimum altitudes recorded were 1280 and 30 m above sea level respectively. Maximum and minimum average ambient temperatures (AAT) were 27.9ºC and 6.1ºC respectively. Maximum and minimum average environmental pressure (AEP) was 239 mm and 2 mm respectively. All sites had a dry season lasting from 6 to 11 months. These results will contribute to an epidemiological study by providing data on climatic features.Peer reviewe

Transmisión experimental de geminivirus por Bemisia tabaci a diferentes cultivares de poroto

Trabajo presentado al XXXII Congreso Argentino de Horticultura, celebrado del 23-26 de septiembre 2009, en Salta, Argentina.Peer reviewe

Co-infection with a wheat rhabdovirus causes a reduction in Mal de Río Cuarto virus titer in its planthopper vector

Mal de Río Cuarto virus (MRCV, Fijivirus, Reoviridae) causes one of the most important diseases in maize (Zea mays L.) in Argentina and has been detected in mixed infections with a rhabdovirus closely related to Maize yellow striate virus. In nature both viruses are able to infect maize and several grasses including wheat, and are transmitted in a persistent propagative manner by Delphacodes kuscheli Fennah (Hemiptera: Delphacidae). This work describes the interactions between MRCV and rhabdovirus within their natural vector and the consequences of such co-infection regarding virus transmission and symptom expression. First- and third-instar D. kuscheli nymphs were fed on MRCV-infected wheat plants or MRCV-rhabdovirus-infected oat plants, and two latency periods were considered. Transmission efficiency and viral load of MRCV-transmitting and non-transmitting planthoppers were determined by real-time quantitative polymerase chain reaction analysis (RTqPCR). Vector transmission efficiency was related to treatments (life stages at acquisition and latency periods). Nevertheless, no correlation between transmission efficiency and type of inoculum used to infect insects with MRCV was found. Treatment by third-instar nymphs 17 days after Acquisition Access Period was the most efficient for MRCV transmission, regardless of the type of inoculum. Plants co-infected with MRCV and rhabdovirus showed the typical MRCV symptoms earlier than plants singly infected with MRCV. The transmitting planthoppers showed significantly higher MRCV titers than non-transmitting insects fed on single or mixed inocula, confirming that successful MRCV transmission is positively associated with viral accumulation in the insect. Furthermore, MRCV viral titers were higher in transmitting planthoppers that acquired this virus from a single inoculum than in those that acquired the virus from a mixed inoculum, indicating that the presence of the rhabdovirus somehow impaired MRCV replication and/or acquisition. This is the first study about interactions between MRCV and a rhabdovirus closely related to Maize yellow striate virus in this insect vector (D. kuscheli), and contributes to a better understanding of planthopper-virus interactions and their epidemiological implications.Fil: Dumón, Analía Delina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Argüello Caro, Evangelina Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Mattio, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Alemandri, M. V.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: del Vas, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biotecnología y Biología Molecular; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas; ArgentinaFil: Truol, Graciela Ana. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentin

Aparición de un aislado estrechamente relacionado con el Maize yellow striate virus en plantas de trigo

In Argentina, wheat fields have exhibited virus-like symptoms, such as chlorotic streaking, dwarfing, yellowing and empty ears since 2007. Symptomatic plants and leaves samples were collected in Marcos Juárez (2007) and Río Cuarto (2008 and 2013), both of them in Córdoba province. The virus was experimentally transmitted from symptomatic wheat plants to wheat cv. Baguette 10 and cv. BioINTA 3005 using the vector Delphacodes kuscheli Fennah (Delphacidae); symptoms of chlorotic streaking, dwarfing and yellowing appeared in the inoculated cereals at 10–15 days post-inoculation. Virus presence was confirmed by electron microscopy and RT-PCR using degenerated primers, which amplified a conserved region of the plant rhabdovirus polymerase (L) gene. Sequence comparison showed 98% nucleotide identity with Maize yellow striate virus C. Caroya (JQ715419) isolated from corn in Argentina. To our knowledge, this is the first report of the occurrence of Maize yellow striate virus in wheat in Argentina.En la Argentina, desde 2007 se han observado síntomas similares a virus en campos de trigo, tales como rayas cloróticas, enanismo y amarillamiento. Se tomaron muestras de plantas y hojas sintomáticas de Marcos Juárez (2007) y de Río Cuarto (2008 y 2013), ambas localidades de la provincia de Córdoba. El virus fue transmitido experimentalmente a partir de plantas de trigo sintomáticas a los cultivares Baguette 10 y BIOINTA 3005, utilizando el vector Delphacodes kuscheli Fennah (Delphacidae); los síntomas de rayas cloróticas, enanismo y amarillamiento en los cereales inoculados se reprodujeron a los 10-15 días posinoculación. La presencia de virus se confirmó por microscopía electrónica y RT-PCR usando cebadores degenerados, que amplifican una región conservada del gen de la polimerasa (L) de los rhabdovirus de plantas. La comparación de secuencias mostró 98% de identidad de nucleótidos con el Maize yellow striate virus C. Caroya (JQ715419) aislado de maíz en Argentina. Hasta el momento, este es el primer reporte de la presencia del Maize yellow striate virus en trigo en la Argentina

Identificación y caracterización biológica del Barley yellow striate mosaic virus (BYSMV): nueva enfermedad del trigo en Argentina

El cultivo de trigo (Triticum aestivum L.), es el cereal de invierno de mayor importancia económica en Argentina. Su producción se halla limitada por diversos factores, entre ellos las enfermedades virales. El objetivo del presente trabajo fue identificar y caracterizar biológicamente una enfermedad viral detectada recientemente en el cultivo de trigo en Argentina, que ha presentado elevada incidencia en los últimos años. Para ello, se recolectaron plantas con síntomas en localidades de: Miramar y Balcarce (Buenos Aires), Río Cuarto, Rosales y Marcos Juárez (Córdoba), Paraná (Entre Ríos) y General Pico (La Pampa) de la región triguera Argentina. Las muestras fueron caracterizadas a través de: microscopia electrónica ("leaf-dip" y cortes ultrafinos), serología (con antisueros para diferentes virosis del trigo por DAS-ELISA y ELISA indirecto), transmisión mecánica, por semilla y por vectores (delfácidos), rango de hospedantes diferenciales y susceptibilidad diferencial de diferentes cultivares de trigo en infecciones naturales. Los resultados obtenidos evidenciaron que esta nueva enfermedad es causada por el Barley yellow striate mosaic virus (BYSMV) (Rhabdoviridae-Cytorhabdovirus), un virus ampliamente distribuido a nivel mundial y que representa un riesgo potencial para otros cultivos como cebada, avena y triticale. Este trabajo representa el primer reporte del BYSMV en Argentina