The psorosis disease of citrus: a pale light at the end of the tunnel

First reported in 1896, psorosis was the first citrus disease proven to be graft transmissible and also the first for which eradication and budwood certification programs were launched to prevent its economic damage. For many years psorosis etiology remained elusive, and only in 1986 was the disease associated with the presence of virus-like particles in infected plants. However, in the last 2 decades a virus with unusual morphology (Citrus psorosis virus, CPsV) was characterized and closely associated with psorosis disease as previously defined by field symptoms and by biological indexing in sensitive indicator plants. With a tripartite, negative-sense, RNA genome and a ~48 kDa coat protein, CPsV, the presumed causal agent of psorosis, is the type member of the genus Ophiovirus, within the new family Ophioviridae. Availability of the complete genomic sequence of 2 CPsV isolates and partial sequences of many others has enabled i) setting up rapid and sensitive RNA-based detection methods, ii) testing different citrus and relatives for resistance to CPsV, iii) identification of the 2 components (psorosis A and psorosis B) traditionally associated with non-scaled and scaled bark inoculum, respectively, from psorosis-infected plants and study their interactions, iv) analysis of genetic variation and evolutionary forces shaping the CPsV populations, v) preliminary studies on the interactions between virus and host factors, and vi) development of transgenic citrus plants expressing variable degrees of resistance to CPsV. In summary, 120 years after the first report on psorosis we start seeing a pale light at the end of the tunnel.Instituto de Biotecnologia y Biologia Molecula

La autobiografía femenina como mecanismo de traducción de la vida fingida

A pesar de los esfuerzos de George D. Painter en su estudio sobre Marcel Proust' nunca se ha podido saber la identidad de la misteriosa dama, capital en la evolución de A la búsqueda del tiempo perdido. Como tampoco se ha llegado a descubrir quién fue el amor secreto de Bécquer más allá de la celda simbólica del poeta. Claro que ante estas afirmaciones se puede objetar que hablamos de textos no pertenecientes al género autobiográfico. Sin embargo he citado expresamente a dos autores en los que la ficcionalidad narrativa se alimenta de vivencias personales, impostándolas bajo un personaje ficticio. Y que, en un sentido inverso, es la criatura literaria la que aporta entidad al autor, completo anónimo sin ell

Recepción y traducciones en España del teatro de Edward Albee

P. 91-110Edwuard Albee constituye el ejemplo de autor maldito de la dramaturgia americana de la segunda mitad dle siglo XX. Su trayectoria vital, llena de dolorosos episodios, reflejados luego en sus obras, sus piezas teatrales aferradas ideológicamente a un cruel retrato de la sociedad americana y desprendidas al tiempo de estas mediante una estructura que baraja el inconsciente y los mecanismos del absurdo,así como su actitud agresiva frente al público y la crítica le han convertido en objeto de atención para los estudiosos

First molecular determination of herpesvirus from two mysticete species stranded in the Mediterranean Sea

BACKGROUND Herpesvirus can infect a wide range of animal species: mammals, birds, reptiles, fish, amphibians and bivalves. In marine mammals, several alpha- and gammaherpesvirus have been identified in some cetaceans and pinnipeds species. To date, however, this virus has not been detected in any member of the Balaenoptera genus. CASE PRESENTATION Herpesvirus was determined by molecular methods in tissue samples from a male fin whale juvenile (Balaenoptera physalus) and a female common minke whale calf (Balaenoptera acutorostrata) stranded on the Mediterranean coast of the Region of Valencia (Spain). Samples of skin and penile mucosa from the fin whale and samples of skin, muscle and central nervous system tissue from the common minke whale tested positive for herpesvirus based on sequences of the DNA polymerase gene. Sequences from fin whale were identical and belonged to the Alphaherpesvirinae subfamily. Only members of the Gammaherpesvirinae subfamily were amplified from the common minke whale, and sequences from the muscle and central nervous system were identical. Sequences in GenBank most closely related to these novel sequences were viruses isolated from other cetacean species, consistent with previous observations that herpesviruses show similar phylogenetic branching as their hosts. CONCLUSIONS To our knowledge, this is the first molecular determination of herpesvirus in the Balaenoptera genus. It shows that herpesvirus should be included in virological evaluation of these animals

Changes in the Bark Proteins of Sour Orange Rootstock Induced by Citrus Tristeza Virus

The effect of citrus tristeza virus (CTV) infection on bark proteins of several citrus rootstocks was studied by polyacrylamide gel electrophoresis (SDSPAGE). A protein band (P6) from bark of sour orange grafted with sweet orange, grapefruit or clementine scions had lower intensity in CTV-infected than in CTV-free trees. Decrease of P6 intensity was more conspicuous in trees infected with a severe CTV isolate than in those infected with a mild isolate. No difference was observed between bark proteins of CTV infected and CTV-free sour orange sprouts. Protein profiles of healthy and tristeza-infected Troyer citrange or Cleopatra mandarin, grafted with navel orange, were also indistinguishable. Finally, protein patterns of sour orange grafted with navel orange, severely declined from Phytophthora sp. or psorosis, were similar to those of non-declined controls. Thus, decreased intensity of P6 seems to be specifically associated with tristeza in citrus trees grafted on sour orange

Segregation of Citrus Tristeza Virus Strains Evidenced by Double Stranded RNA (dsRNA) Analysis

A field isolate of citrus tristeza virus (CTV), T-385, was separated from other virus and virus-like diseases by aphid transmission to Mexican lime seedlings. This isolate did not cause decline of sweet orange on sour orange rootstock under field conditions and it induced mild vein clearing and an inconspicuous stem pitting on Mexican lime. Two months after aphid transmission, one of the infected lime seedlings was used as an inoculum source to graft-inoculate 40 citron plants. Two years later, the citron plants were analysed individually for dsRNA content and up to 23 different electrophoretic profiles were found. DsRNA analysis has been repeated three times through the year and the individual patterns remained unchanged. Thirteen of these CTV sub-isolates were graft-transmitted to sweet orange seedlings and the corresponding dsRNA profiles were identical to those previously obtained from citron. All these subisolates induced mild symptoms of Mexican lime similar to those of the original isolate (T-385). These results substantiate that several CTV strains can infect a single citrus plant

Discrimination Between Mild and Severe Citrus tristeza virus Isolates with a Rapid and Highly Specific Real-Time Reverse Transcription-Polymerase Chain Reaction Method Using TaqMan LNA Probes

Severe isolates of Citrus tristeza virus (CTV) inducing seedling yellows (SY) and/or stem pitting (SP) in grapefruit or sweet orange are a major threat for the citrus industry worldwide. Identification of these CTV variants was achieved by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) using a general primer set and three TaqMan locked nucleic acids (LNA) probes targeting sequences characteristic of severe, mild (non-SY, non-SP), and T36-like isolates. Successful amplification was achieved from fresh or silica-desiccated CTV-infected samples and all isolates but one reacted with one or more probes. Standard curves using RNA transcripts homologous to the three probes allowed a reproducible quantitative assay, with a wide dynamic range of detection starting with 102 copies. RT-PCR assays with homologous and heterologous transcript RNA mixes demonstrated that each probe reacted only with its cognate sequence which was detected even at ratios below 2.5%. Analysis of 56 pathogenically distinct CTV isolates from 20 countries showed that mild isolates reacted only with the mild probe, whereas severe SP and SY isolates reacted with the severe-SP or the T36-like probes, respectively, and often with a second probe. This procedure can be useful to identify and control potentially dangerous CTV isolates in areas affected only by mild isolates

First molecular detection and characterization of herpesvirus and poxvirus in a Pacific walrus (Odobenus rosmarus divergens)

BACKGROUND Herpesvirus and poxvirus can infect a wide range of species: herpesvirus genetic material has been detected and amplified in five species of the superfamily Pinnipedia; poxvirus genetic material, in eight species of Pinnipedia. To date, however, genetic material of these viruses has not been detected in walrus (Odobenus rosmarus), another marine mammal of the Pinnipedia clade, even though anti-herpesvirus antibodies have been detected in these animals. CASE PRESENTATION In February 2013, a 9-year-old healthy captive female Pacific walrus died unexpectedly at L'Oceanografic (Valencia, Spain). Herpesvirus was detected in pharyngeal tonsil tissue by PCR. Phylogenetic analysis revealed that the virus belongs to the subfamily Gammaherpesvirinae. Poxvirus was also detected by PCR in skin, pre-scapular and tracheobronchial lymph nodes and tonsils. Gross lesions were not detected in any tissue, but histopathological analyses of pharyngeal tonsils and lymph nodes revealed remarkable lymphoid depletion and lymphocytolysis. Similar histopathological lesions have been previously described in bovine calves infected with an alphaherpesvirus, and in northern elephant seals infected with a gammaherpesvirus that is closely related to the herpesvirus found in this case. Intracytoplasmic eosinophilic inclusion bodies, consistent with poxviral infection, were also observed in the epithelium of the tonsilar mucosa. CONCLUSION To our knowledge, this is the first molecular identification of herpesvirus and poxvirus in a walrus. Neither virus was likely to have contributed directly to the death of our animal

Genetic variation of populations of Citrus psorosis virus

Citrus psorosis virus (CPsV), the type species of genus Ophiovirus, has a segmented, negative-stranded RNA genome. We examined the population structure and genetic variation of CPsV in three coding regions located in RNAs 1, 2 and 3, analysing 22 isolates from Argentina, California, Florida, Italy and Spain. Most isolates contained a predominant sequence and some minor variants. Estimations of the genetic diversity and phylogenetic clustering of isolates disclosed two populations, one comprising isolates from Spain, Italy, Florida and California and the other including the Argentinean isolates. Isolate CPV-4 (from Texas) included for comparison was distant from both groups, suggesting that it belongs to a third group. The low ratio between non-synonymous and synonymous nucleotide substitutions indicated strong selection for amino acid sequence conservation, particularly in the coat protein gene. Incongruent phylogenetic relationships in different genomic regions suggested that exchange of genomic segments may have contributed to CPsV evolution.Instituto de Biotecnologia y Biologia Molecula