Is there any genetic variation among native mexican and argentinian populations of Dalbulus maidis (Hemiptera: Cicadellidae)?.

The corn leafhopper Dalbulus maidis (Delong & Wolcott) (Hemiptera: Cicadellidae) originated in Mexico, but is found from southeastern and southwestern USA to Argentina. Differences in reproductive and phenotypic traits between Mexican (native) and Argentinian (adventive) populations have been previously reported, but information on their genetic variation is currently unavailable. The objective was to investigate possible genetic variability among D. maidis populations collected in Mexico on maize and maize relatives (annual and perennial teosintes) and on maize in Argentina. A region of the mitochondrial gene coding for the cytochrome oxidase subunit I (mtCOI) and the ribosomal internal transcribed spacer (ITS2) were sequenced and analyzed. We developed the forward and reverse primers for the DNA amplification of COI in D. maidis (dalCOI). Twenty two and 17 sequences for dalCOI and ITS2, respectively, were generated and analyzed. No genetic variation among Mexican and Argentinian populations was found in the ribosomal region and low genetic variation was found in the mitochondrial region. These results could be explained by the short evolutionary time scale, since both maize and the corn leafhopper moved throughout the Americas only in the most recent millenia, or in part to the limited host range, and thus a limited change in the corn leafhopper associated bacteria.Fil: Palomera, Veronica. Universidad de Guadalajara; MéxicoFil: Bertin, Sabrina. Universidad de Torino ; ItaliaFil: Rodriguez, Aaron. Universidad de Guadalajara; MéxicoFil: Bosco, Domenico. Universidad de Torino; ItaliaFil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Moya-Raygoza, Gustavo. Universidad de Guadalajara; Méxic

Indigenous and introduced species of the Bemisia tabaci complex in sweet potato crops from Argentina

La batata (Ipomoea batatas (L.) Lam) es uno de los cultivos más importantes en el mundo. Recientemente se observó una severa sintomatología viral en cultivos de la región pampeana argentina, en la que están identificados begomovirus y crinivirus, ambos transmitidos exclusivamente por mosca blanca. El objetivo de este estudio fue identificar las especies de B. tabaci en cultivos de batata en Colonia Caroya, mediante el análisis de secuencias mitocondriales de la citocromo oxidasa subunidad I (mtCOI). Se identificaron dos haplotipos (especies crípticas) ya descriptos en el mundo: New World2 (especie nativa) y MEAM1 (especie introducida). Los resultados indican la presencia de ambas especies, las cuales son potenciales vectores de begomovirus y crinivirus en batata en Argentina.Sweet potato (Ipomoea batatas (L.) Lam) is one of the most important crops worldwide. Recently, the appearance of severe viral symptoms has been observed in sweet potato crops in the pampas region of Argentina and both begomovirus and crinivirus, exclusively transmitted by whiteflies, have been identified. The aim of this study was to identify B. tabaci species from sweet potato crops in Colonia Caroya by analysing mitochondrial cytochrome c oxidase subunit I (mtCOI) sequences. Two previously described haplotypes were identified: New World2 (indigenous species) and MEAM1 (introduced species). The results indicate the presence of both species, which are potential vectors of begomovirus and crinivirus in Argentina.Fil: Alemandri, V.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; ArgentinaFil: Martino, Julia Andrea. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Feo, Liliana del Valle. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Truol, G.. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigaciones Agropecuarias. Instituto de Patología Vegetal; Argentin

Impact of host plant species and whitefly species on feeding behavior of Bemisia tabaci

Whiteflies of the Bemisia tabaci species complex are economically important pests of cassava. In Africa, they cause greatest damage through vectoring viruses responsible for cassava mosaic disease and cassava brown streak disease. Several cryptic species from the B. tabaci complex colonize cassava and neighboring crops, but the feeding interactions between the different crops and B. tabaci species are unknown. The electrical penetration graph (EPG) technique makes it possible to conduct detailed feeding studies of sap-sucking insects by creating an electric circuit through the insect and the plant. The apparatus measures the voltage fluctuations while the wired-up insect feeds and produces graphs that describe feeding behavior. We utilized EPG to explore the feeding behavior of cassava-colonizing whiteflies (SSA1-SG3) on cassava, sweet potato, tomato, and cotton; and sweet potato-colonizing whiteflies (MED and IO) on cassava and sweet potato. Results show that: (1) feeding of SSA1-SG3 is not restricted to cassava. The least preferred host for SSA1-SG3 was tomato, where probing was delayed by 99 min compared to 10 min on other hosts, furthermore mean duration of phloem ingestion events was 36 min compared to 260 min on cassava. (2) Feeding of MED on cassava appeared to be non-functional, as it was characterized by short total phloem ingestion periods (5 h). (3) Wire diameter affects the feeding in a statistically and practically significant manner. Implications for whitefly control and studies of host whitefly resistance are discussed.</p

Identifikasi Thrips Alliorum (Priesner), Thrips Hawaiiensis (Morgan), dan Thrips Parvispinus (Karny) Berdasarkan Variasi DNA COI Mitokondria

Genus Thrips adalah genus kedua terbesar Ordo Thysanoptera yang sebagian besar anggotanya bersifat polifag dan beberapa spesies merupakan hama serius pada tanaman sayuran. Kerusakan yang ditimbulkan oleh trips dapat menyebabkan kehilangan hasil 30–50%. Thrips alliorum (Priesner), T. hawaiiensis (Morgan), dan T. parvispinus (Karny) banyak dilaporkan menjadi hama pada pertanaman terutama pertanaman hortikultura. Penggunaan karakter molekuler, seperti runutan DNA fragmen gen Cytochrome Oxydase I mitokondria (mtCOI) dapat digunakan untuk identifikasi spesies atau konfirmasi hasil identifikasi dengan menggunakan karakter morfologi. Tujuan penelitian ini adalah mengidentifikasi T. alliorum, T. hawaiiensis, dan T. parvispinus berdasarkan runutan DNA fragmen gen mtCOI. Identifikasi molekular dilakukan melalui tiga tahap, yaitu koleksi sampel dan isolasi DNA, amplifikasi DNA menggunakan polimerase chain reaction (PCR), dan analisis hasil runutan DNA. Hasil penelitian ini menunjukkan bahwa runutan DNA fragmen mtCOI T. alliorum, T. hawaiiensis, dan T. parvispinus memiliki panjang basa 678, 690, dan 668 pb yang didominasi oleh basa A dan T dengan nilai variasi nukleotida sebesar 25,18%. Identifikasi tiga spesies trips T. alliorum, T. hawaiiensis, dan T. parvispinus berdasarkan runutan DNA fragmen mtCOI menunjukkan hasil yang sama dengan identifikasi berdasarkan karakter morfologi

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

A molecular method for the identification of resting eggs of acartiid copepods in the Thau lagoon, France

Acartia and Paracartia species, often known to co-occur, can exhibit complex life cycles, including the production of resting eggs. Studying and understanding their population dynamics is hindered by the inability to identify eggs and early developmental stages using morphological techniques. We have developed a simple molecular technique to distinguish between the three species of the Acartiidae family (Acartia clausi, A. discaudata and Paracartia grani) that co-occur in the Thau lagoon (43�250N; 03�400E) in southern France. Direct amplification of a partial region of the mitochondrial cytochrome oxidase I gene by polymerase chain reaction and subsequent restriction fragment length polymorphism results in a unique restriction profile for each species. The technique is capable of determining the identity of individual eggs, including resting eggs retrieved from sediment samples, illustrating its application in facilitating population dynamic studies of this ubiquitous and important member of the zooplankton community

Unraveling the intricate biodiversity of the benthic harpacticoid genus ��it��Nannopus��/it�� (Copepoda, Harpacticoida, Nannopodidae) in Korean waters

Nannopus (Harpacticoida, Nannopodidae) species are abundant and widely distributed throughout the world across a variety of habitats. Nannopus is well known for high frequencies of misidentifications and thus may comprise several cryptic complexes and morphologically distinct species. Cryptic taxa are common in meiofauna communities. In this study, we aimed to identify Nannopus species using an integrative approach including molecular taxonomy. We adopted a non-destructive DNA extraction method so that morphological and molecular data could be obtained from the same specimen. We analyzed the molecular diversity and distributions of Nannopus using a total of 190 individuals. We sequenced the 190 mtCOI, 53 mtCYTB, 25 18SrDNA, and 4328SrDNA genes from 190 individuals. Several species delimitation approaches were applied, including uncorrected p-distances for mtCOI, mtCYTB, 18SrDNA, and 28SrDNA, and Automatic Barcode Gap Discovery and Bayesian implemented Poisson tree processes for mtCOI and mtCYTB data. The maximum likelihood and Bayesian approaches were used to examine the phylogenetic relationships among individuals using the combined set of all four genes. Our species delimitation and phylogenetic analyses indicated the presence of three cryptic and six morphologically distinct species. All species are sympatric and widely distributed across mudflats ranging from the Yellow Sea to the South Sea in Korea. The divergence patterns of the four genes were not congruent. A phylogenetic tree based on the concatenated dataset was the most robust, was congruent with morphology, and suggested two major clades. We considered the validity of reinstating the genus Ilyophilus (Lilljeborg, 1902) and ultimately concluded that including all congeners in Nannopus until the type species (N. palustris Brady, 1880) is re-described was the most prudent approach.We would like to thank Jeongho Kim for assisting in the collection of sediments from type localities. We are very grateful to Dr. Terue Cristina Kihara, and her institute (DZMB, Germany) for permitting us to use the photo of confocal image for graphical abstract. This study was supported by a grant entitled &quot;Discovery project of endemic species in Korea&quot; from the National Institute of Biological Resources funded by the Ministry of Environment, Korea (NIBR 201601201), and a grant (2018R1D1A1B07050117) from Korea Research Foundation, and the BK21 Plus Program (Eco-Bio Fusion Research Team, 22A20130012352) funded by the Ministry of Education (MOE, Korea) to WL. This work was additionally supported by National Research Foundation of Korea Grant (2018R1C1B3001650) and the Chung-Ang University Research Grant in 2017 to SE

A new Pseudodiaptomus (Copepoda, Calanoida) from Korea supported by molecular data

A new species, Pseudodiaptomus koreanus sp. nov. (Calanoida, Pseudodiaptomidae), which has so far been identified as P. inopinus Burckhardt, 1913, is described from Korean estuaries. This new species differs from P. inopinus in the broad and short posterior process of the female genital flap, rounded posteriocentral projection between the gonopores, presence of a posterodorsal spinule on the fifth pediger of the male, and a row of fine ventral spinules on the male second urosomite. The new species is also distinguishable from P. nansei Sakaguchi and Ueda, 2010 by the presence of a row of fine spinules along posterior margins of the second and third pedigers in both sexes, rounded posteromedial projection between the gonopores, separation of ancestral segment XXI and compound segments XXII-XXIII of the male right antennules, and a row of fine ventral spinules on the male second urosomite.Their ribosomal internal transcribed spacer 1 (ITS 1) and mitochondrial gene cytochrome oxidase subunit I (mtCOI) sequences supported the conclusion based on morphological data, with considerable divergence values between P. koreanus and P. inopinus: 12-14% for ITS 1 and 14-22% for mtCOI. The ITS 1 and mtCOI sequences of specimens of two morphs of P. koreanus with different male fifth legs differed by &amp;lt;1.2% for ITS1 and &amp;lt;3.5% for mtCOI, suggesting that these morphological differences represent interspecific variability.We would like to thank Professor Hiroshi Ueda (Kochi University) for providing specimens of Pseudodiaptomusinopinus from Rokkaku River, western Japan. We also express our sincere thanks to two anonymous reviewers forreasonable criticism that improved the text. This study was partly supported by the National Institute of BiologicalResources (NIBR), Korean project on the survey of Korean indigenous species