Presencia en Valencia de Rhizoecus cacticans (Hambl.) (Homoptera, pseudococcidae)

En el presente artículo se advierte de la presencia del pseudococcino Rhizoecus cacticans (HAMBLETON) en la zona de Valencia, atacando a raíces de cactáceas. Se dan algunas características del género y se describe la especie, así como algunos datos sobre los daños que causa. Se indican procedimientos posibles de control.The presence of the mealybug Rhizoecus cacticans (HAMBL.) (Homoptera: Pseudococcidae) is reported in the Valencia area. The insect causes injuries in the root zone in cactáceas. Some characteristics of the genus are indicated and a description of the specie is done. Data on the damages caused is also presented. Tentative control methods are outlined

A survey of potential vectors of apricot chlorotic leaf roll

A comparative survey was done in leafhopper populations captured in apricot orchards in two areas of Valencia, one with considerable natural spread of apricot chlorotic leaf roll (ACLR), and the other where such natural spread is virtually nonexistent. An identification of the leafhopper species found in the first and in the second area suggest that Neoaliturus haematoceps and/or Neoaliturus fertestratus are the potential vectors of ACLR, at least under the conditions of Valencia province. Psammotettix striatus and Austroagallia sinuata are potential secondary vextors of ACLR

Inspirations on virus replication and cell-to-cell movement from studies examining the cytopathology induced by lettuce infectious yellows virus in plant cells

Lettuce infectious yellows virus (LIYV) is the type member of the genus Crinivirus in the family Closteroviridae. Like many other positive-strand RNA viruses, LIYV infections induce a number of cytopathic changes in plant cells, of which the two most characteristic are: Beet yellows virus-type inclusion bodies composed of vesicles derived from cytoplasmic membranes; and conical plasmalemma deposits (PLDs) located at the plasmalemma over plasmodesmata pit fields. The former are not only found in various closterovirus infections, but similar structures are known as ‘viral factories’ or viroplasms in cells infected with diverse types of animal and plant viruses. These are generally sites of virus replication, virion assembly and in some cases are involved in cell-to-cell transport. By contrast, PLDs induced by the LIYV-encoded P26 non-virion protein are not involved in replication but are speculated to have roles in virus intercellular movement. These deposits often harbor LIYV virions arranged to be perpendicular to the plasma membrane over plasmodesmata, and our recent studies show that P26 is required for LIYV systemic plant infection. The functional mechanism of how LIYV P26 facilitates intercellular movement remains unclear, however, research on other plant viruses provides some insights on the possible ways of viral intercellular movement through targeting and modifying plasmodesmata via interactions between plant cellular components and viral-encoded factors. In summary, beginning with LIYV, we review the studies that have uncovered the biological determinants giving rise to these cytopathological effects and their importance in viral replication, virion assembly and intercellular movement during the plant infection by closteroviruses, and compare these findings with those for other positive-strand RNA viruses

Barley Yellow Dwarf Virus (BYDV) y los áfidos en los arrozales levantinos: una prospección

Se ha llevado a cabo una prospección de las poblaciones emigrantes de áfidos alados en el área de La Albufera de Valencia, zona donde se da el «enrojat» del arroz, enfermedad causada por una raza del Barley Yellow Dwarf Virus, y se discute aquí el potencial presumible de las distintas especies como vectores de la enfermedad. Se muestrearon dos áreas con diferente incidencia de la enfermedad, obteniéndose 30 especies, de las que ocho están descritas como vectores de tales virus. Fueron mayores las capturas en las áreas donde se cultivaba el arroz por plantel y transplante con incidencia marcada de la enfermedad, que en otras de menor incidencia. La aparente homogeneidad de la zona hace difícil comprender la razón de tales diferencias. Entre los vectores conocidos de BYDV, sólo Rhopalosiphon padi L. y Hyaiopterus pruni (L) Geof. aparecieron al principio de la estación, cuando tiene lugar la infección, con poblaciones considerables. E1 primero es el vector conocido de la enfermedad. El segundo, es de las pocas especies que tiene niveles similares de captura en ambas áreas. Ninguno de los otros áfidos vectores capturados como alados parece verdaderamente importante para la transmisión a pleno campo por lo tardío de su llegada a los campos o por razones de su ciclo vital. Se ha intentado estudiar el potencial de Hyalopterus pruni, pulgón muy abundante en los carrizos como transmisor a corta distancia a partir de estas plantas. No se han obtenido resultados positivos ni a partir de la planta, ni a partir de áfidos alimentados en arroz o avena infectadas previamente con la enfermedad.A prospection of the álate aphid was made on the Spanish central Mediterranean area of paddy rice. Their potential for Barley Yellow Dwarf transmission was discused. Areas closeby with different incidence of the disease «enrojat» as it is called, were sampled for oncoming alate aphids. More than 30 species were caught, eight of them known as potential vectors for BYDV transmission. Aphid catches were markedly bigger on the traditional nursery planted area with high incidence than in the low incidence area. The apparent homogenity of the country and the crop does not permit to ascertain the reason for such differences. Between the BYDV known vectors, only Rhopalosiphon padi L. and Hyalopterus pruni (L.) Geof. ocurred early in the season with high populations. The former one is the known vector of the rice disease. The second, as exception, appearent at similar extent in both areas of sampling. No other potential vector seems to be important on the natural transmission of the BYDV to the rice because its late arrival or due to their cycle characteristics. Au study was developed to ascertain the potential of the Hyalopterus pruni as short disunce vector for BYDV from its hosts Phragmites comunis, where is prevalent on very high population all along the year. N o positive result was obtained from this weed material or was transmitted by such aphid

A Thioredoxin Domain-Containing Protein Interacts with Pepino mosaic virus Triple Gene Block Protein 1

Pepino mosaic virus (PepMV) is a mechanically-transmitted tomato pathogen of importance worldwide. Interactions between the PepMV coat protein and triple gene block protein (TGBp1) with the host heat shock cognate protein 70 and catalase 1 (CAT1), respectively, have been previously reported by our lab. In this study, a novel tomato interactor (SlTXND9) was shown to bind the PepMV TGBp1 in yeast-two-hybrid screening, in vitro pull-down and bimolecular fluorescent complementation (BiFC) assays. SlTXND9 possesses part of the conserved thioredoxin (TRX) active site sequence (W__PC vs. WCXPC), and TXND9 orthologues cluster within the TRX phylogenetic superfamilyclosesttophosducin-likeprotein-3. InPepMV-infectedandhealthyNicotianabenthamiana plants,NbTXND9mRNAlevelswerecomparable,andexpressionlevelsremainedstableinbothlocal and systemic leaves for 10 days post inoculation (dpi), as was also the case for catalase 1 (CAT1). To localize the TXND9 in plant cells, a polyclonal antiserum was produced. Purified α-SlTXND9 immunoglobulin (IgG) consistently detected a set of three protein bands in the range of 27–35 kDa, in the 1000 and 30,000 g pellets, and the soluble fraction of extracts of healthy and PepMV-infected N. benthamiana leaves, but not in the cell wall. These bands likely consist of the homologous protein NbTXND9 and its post-translationally modified derivatives. On electron microscopy, immuno-gold labellingofultrathinsectionsofPepMV-infectedN.benthamianaleavesusingα-SlTXND9IgGrevealed particle accumulation close to plasmodesmata, suggesting a role in virus movement. Taken together, this study highlights a novel tomato-PepMV protein interaction and provides data on its localization in planta. Currently, studies focusing on the biological function of this interaction during PepMV infection are in progress

Cucumis metuliferus es resistente a poblaciones de Meloidogyne spp. incluso virulentas al gen MI

Se realizaron diversos ensayos para determinar la respuesta de C. metuliferus frente diversas poblaciones de Meloidogyne arenaria, M. incognita y M. javanica, algunas de las cuales habían sido ya caracterizadas como virulentas al gen de resistencia Mien tomatePostprint (published version