The DNA methyltransferase inhibitor decitabine blunts the response to a high animal fat and protein diet in mice.

Increasing evidence hints that DNA hypermethylation may mediate the pathogenic response to cardiovascular risk factors. Here, we tested a corollary of that hypothesis, i.e., that the DNA methyltransferase inhibitor decitabine (Dec) ameliorates the metabolic profile of mice fed a moderately high-animal fat and protein diet (HAFPD), a proxy of cardiovascular risk-associated Western-type diet. HAFPD-fed mice were exposed to Dec or vehicle for eight weeks (8W set, 4-32/group). To assess any memory of past exposure to Dec, we surveyed a second mice set treated as 8W but HAFPD-fed for further eight weeks without any Dec (16W set, 4-20/group). In 8W, Dec markedly reduced HAFPD-induced body weight gain in females, but marginally in males. Characterization of females revealed that Dec augmented skeletal muscle lipid content, while decreasing liver fat content and increasing plasma non-esterified fatty acids, adipose insulin resistance, and -although marginally- whole blood acylcarnitines, compared to HAFPD alone. Skeletal muscle mitochondrial DNA copy number was higher in 8W mice exposed to HAFPD and Dec, or in 16W mice fed HAFPD only, relative to 8W mice fed HAFPD only, but Dec induced a transcriptional profile indicative of ameliorated mitochondrial function. Memory of past Dec exposure was tissue-specific and sensitive to both duration of exposure to HAFPD and age. In conclusion, Dec redirected HAFPD-induced lipid accumulation towards the skeletal muscle, likely due to augmented mitochondrial functionality and increased lipid demand. As caveat, Dec induced adipose insulin resistance. Our findings may help identifying strategies for prevention and treatment of lipid dysmetabolism.

Clinical Characteristics and Outcomes of Patients with Heart Failure of Hypertensive Etiology: Analysis of Colombian Heart Failure Registry (RECOLFACA).

INTRODUCTION: Arterial hypertension represents one of the main comorbidities observed in patients with heart failure (HF) and one of the main risk factors for its development. Despite this, studies assessing this hypertensive etiology are scarce in Latin America. Our objective was to analyze the prevalence of HF of hypertensive etiology and evaluate its prognosis in patients enrolled in the Colombian Heart Failure Registry (RECOLFACA by its Spanish acronym). METHODS: RECOLFACA recruited adult patients diagnosed with HF in 60 centers in Colombia between 2017 and 2019. The primary outcome was all-cause mortality. A Cox proportional hazards regression model was used to assess factors associated with primary outcomes in patients with hypertensive HF. A p value <0.05 was considered significant. All statistical tests were two-tailed. RESULTS: Out of the total number of patients evaluated in RECOLFACA (n = 2,514), 804 had a diagnosis of HF with hypertensive etiology (31.9%). These patients were less frequently males and had a significantly older age and lower prevalence of comorbidities than those with HF of other etiologies. Additionally, patients with hypertensive HF had a higher prevalence of HF with preserved ejection fraction (HFpEF) (34.1% vs. 28.3%; p = 0.004). Finally, type 2 diabetes mellitus, chronic obstructive pulmonary disease diagnosis, and NYHA class IV were classified as independent mortality risk factors. CONCLUSIONS: Hypertensive HF represents about one-third of the total number of patients with HF in RECOLFACA. Compared with HF of other etiologies, it presents a differential clinical profile - older age and a higher prevalence of HFpEF. RECOLFACA has become a useful tool to characterize patients with HF in Colombia, with which it has been possible to carry out a more specific search and reach the diagnosis of this pathology in our population, and it has served as an example to stimulate registries of patients with HF in other countries in the region.

Transcriptional Response of Vitellogenin Gene in Flatfish to Environmental Pollutants from Two Regions of the Gulf of Mexico.

The present study evaluates the endocrine effect in flatfish through vitellogenin (vtg) gene expression and its association with pollutants data obtained from fish muscle and sediment from two regions in the Gulf of Mexico (GoM): Perdido Fold Belt (northwestern) and the Yucatan Peninsula (southeast). The results revealed induction of vtg in male flatfish in both geographical regions with different levels and patterns of distribution per oceanographic campaign (OC). In the Perdido Fold Belt, vtg was observed in male fish during four OC (carried out in 2016 and 2017), positively associated with Pb, V, Cd and bile metabolites (hydroxynaphthalene and hydroxyphenanthrene). In the Yucatan Peninsula, the induction of vtg in males was also detected in three OC (carried out in 2016 and 2018) mainly associated with Ni, Pb, Al, Cd, V and polycyclic aromatic hydrocarbons. Ultimately, estrogenic alterations could affect reproductive capacity of male flatfish in the GoM.

Alterations in the gut-associated microbiota of juvenile Caribbean spiny lobsters Panulirus argus (Latreille, 1804) infected with PaV1.

The spiny lobster Panulirus argus (Latreille, 1804) is currently affected by an unenveloped, icosahedral, DNA virus termed Panulirus argus virus 1 (PaV1), a virulent and pathogenic virus that produces a long-lasting infection that alters the physiology and behaviour of heavily infected lobsters. Gut-associated microbiota is crucial for lobster homeostasis and well-being, but pathogens could change microbiota composition affecting its function. In PaV1 infection, the changes of gut-associated microbiota are yet to be elucidated. In the present study, we used high-throughput 16S rRNA sequencing technology to compare the bacterial microbiota in intestines of healthy and heavily PaV1-infected male and female juveniles of spiny lobsters P. argus captured in Puerto Morelos Reef lagoon, Quintana Roo, Mexico. We found that basal gut-associated microbiota composition showed a sex-dependent bias, with females being enriched in amplicon sequence variants (ASVs) assigned to Sphingomonas, while males were enriched in the genus Candidatus Hepatoplasma and Aliiroseovarius genera. Moreover, the alpha diversity of microbiota decreased in PaV1-infected lobsters. A significant increase of the genus Candidatus Bacilloplasma was observed in infected lobsters, as well as a significant decrease in Nesterenkonia, Caldalkalibacillus, Pseudomonas, Cetobacterium and Phyllobacterium. We also observed an alteration in the abundances of Vibrio species. Results from this study suggest that PaV1 infection impacts intestinal microbiota composition in Panulirus argus in a sex-dependent manner.

ICTV Virus Taxonomy Profile: Geminiviridae.

The geminiviruses are a family of small, non-enveloped viruses with single-stranded, circular DNA genomes of 2500-5200 bases. Geminiviruses are transmitted by various types of insect (whiteflies, leafhoppers, treehoppers and aphids). Members of the genus Begomovirus are transmitted by whiteflies, those in the genera Becurtovirus, Curtovirus, Grablovirus, Mastrevirus and Turncurtovirus are transmitted by specific leafhoppers, the single member of the genus Topocuvirus is transmitted by a treehopper and one member of the genus Capulavirus is transmitted by an aphid. Geminiviruses are plant pathogens causing economically important diseases in most tropical and subtropical regions of the world. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the Geminiviridae which is available at www.ictv.global/report/geminiviridae.

Two Populations of Viral Minichromosomes Are Present in a Geminivirus-Infected Plant Showing Symptom Remission (Recovery).

UNLABELLED: Geminiviruses are important plant pathogens characterized by circular, single-stranded DNA (ssDNA) genomes. However, in the nuclei of infected cells, viral double-stranded DNA (dsDNA) associates with host histones to form a minichromosome. In phloem-limited geminiviruses, the characterization of viral minichromosomes is hindered by the low concentration of recovered complexes due to the small number of infected cells. Nevertheless, geminiviruses are both inducers and targets of the host posttranscriptional gene silencing (PTGS) and transcriptional gene silencing (TGS) machinery. We have previously characterized a "recovery" phenomenon observed in pepper plants infected with pepper golden mosaic virus (PepGMV) that is associated with a reduction of viral DNA and RNA levels, the presence of virus-related siRNAs, and an increase in the levels of viral DNA methylation. Initial micrococcal nuclease-based assays pinpointed the presence of different viral chromatin complexes in symptomatic and recovered tissues. Using the pepper-PepGMV system, we developed a methodology to obtain a viral minichromosome-enriched fraction that does not disturb the basic chromatin structural integrity, as evaluated by the detection of core histones. Using this procedure, we have further characterized two populations of viral minichromosomes in PepGMV-infected plants. After further purification using sucrose gradient sedimentation, we also observed that minichromosomes isolated from symptomatic tissue showed a relaxed conformation (based on their sedimentation rate), are associated with a chromatin activation marker (H3K4me3), and present a low level of DNA methylation. The minichromosome population obtained from recovered tissue, on the other hand, sedimented as a compact structure, is associated with a chromatin-repressive marker (H3K9me2), and presents a high level of DNA methylation. IMPORTANCE: Viral minichromosomes have been reported in several animal and plant models. However, in the case of geminiviruses, there has been some recent discussion about the importance of this structure and the significance of the epigenetic modifications that it can undergo during the infective cycle. Major problems in this type of studies are the low concentration of these complexes in an infected plant and the asynchronicity of infected cells along the process; therefore, the complexes isolated in a given moment usually represent a mixture of cells at different infection stages. The recovery process observed in PepGMV-infected plants and the isolation procedure described here provide two distinct populations of minichromosomes that will allow a more precise characterization of the modifications of viral DNA and its host proteins associated along the infective cycle. This structure could be also an interesting model to study several processes involving plant chromatin.

Capulavirus and Grablovirus: two new genera in the family Geminiviridae.

Geminiviruses are plant-infecting single-stranded DNA viruses that occur in most parts of the world. Currently, there are seven genera within the family Geminiviridae (Becurtovirus, Begomovirus, Curtovirus, Eragrovirus, Mastrevirus, Topocuvirus and Turncurtovirus). The rate of discovery of new geminiviruses has increased significantly over the last decade as a result of new molecular tools and approaches (rolling-circle amplification and deep sequencing) that allow for high-throughput workflows. Here, we report the establishment of two new genera: Capulavirus, with four new species (Alfalfa leaf curl virus, Euphorbia caput-medusae latent virus, French bean severe leaf curl virus and Plantago lanceolata latent virus), and Grablovirus, with one new species (Grapevine red blotch virus). The aphid species Aphis craccivora has been shown to be a vector for Alfalfa leaf curl virus, and the treehopper species Spissistilus festinus is the likely vector of Grapevine red blotch virus. In addition, two highly divergent groups of viruses found infecting citrus and mulberry plants have been assigned to the new species Citrus chlorotic dwarf associated virus and Mulberry mosaic dwarf associated virus, respectively. These species have been left unassigned to a genus by the ICTV because their particle morphology and insect vectors are unknown.

Colonization by Phloem-Feeding Herbivore Overrides Effects of Plant Virus on Amino Acid Composition in Phloem of Chili Plants.

The 'adaptive host manipulation' hypothesis predicts that parasites can enhance their transmission rates via manipulation of their host's phenotype. For example, many plant pathogens alter the nutritional quality of their host for herbivores that serve as their vectors. However, herbivores, including non-vectors, might cause additional alterations in the plant phenotype. Here, we studied changes in the amino acid (AA) content in the phloem of chilli (Capsicum annuum) plants infected with Pepper golden mosaic virus (PepGMV) upon subsequent colonization with a non-vector, the phloem-feeding whitefly (Trialeurodes vaporariorum). Virus infection alone caused an almost 30-fold increase in overall phloem AAs, but colonization by T. vaporariorum completely reversed this effect. At the level of individual AAs, contents of proline, tyrosine, and valine increased, and histidine and alanine decreased in PepGMV -infected as compared to control plants, whereas colonization by T. vaporariorum caused decreased contents of proline, tyrosine, and valine, and increased contents of histidine and alanine. Overall, the colonization by the whitefly had much stronger effects on phloem AA composition than virus infection. We conclude that the phloem composition of a virus-infected host plant can rapidly change upon arrival of an herbivore and that these changes need to be monitored to predict the nutritional quality of the plant in the long run.

Revision of Begomovirus taxonomy based on pairwise sequence comparisons.

Viruses of the genus Begomovirus (family Geminiviridae) are emergent pathogens of crops throughout the tropical and subtropical regions of the world. By virtue of having a small DNA genome that is easily cloned, and due to the recent innovations in cloning and low-cost sequencing, there has been a dramatic increase in the number of available begomovirus genome sequences. Even so, most of the available sequences have been obtained from cultivated plants and are likely a small and phylogenetically unrepresentative sample of begomovirus diversity, a factor constraining taxonomic decisions such as the establishment of operationally useful species demarcation criteria. In addition, problems in assigning new viruses to established species have highlighted shortcomings in the previously recommended mechanism of species demarcation. Based on the analysis of 3,123 full-length begomovirus genome (or DNA-A component) sequences available in public databases as of December 2012, a set of revised guidelines for the classification and nomenclature of begomoviruses are proposed. The guidelines primarily consider a) genus-level biological characteristics and b) results obtained using a standardized classification tool, Sequence Demarcation Tool, which performs pairwise sequence alignments and identity calculations. These guidelines are consistent with the recently published recommendations for the genera Mastrevirus and Curtovirus of the family Geminiviridae. Genome-wide pairwise identities of 91 % and 94 % are proposed as the demarcation threshold for begomoviruses belonging to different species and strains, respectively. Procedures and guidelines are outlined for resolving conflicts that may arise when assigning species and strains to categories wherever the pairwise identity falls on or very near the demarcation threshold value.

Characterization of Patients With Heart Failure of Chagas Etiology in Colombia: An Analysis Based on the Colombian Registry of Heart Failure (RECOLFACA).

Chronic Chagas cardiomyopathy (CCM) represents a relevant origin of Heart Failure (HF) in countries where the disease is endemic. CCM exhibits distinct myocardial involvement and is associated with a poorer prognosis compared to different HF etiologies. The aim is to explain the features and prognosis of individuals with HF resultant to CCM registered in the Colombian Registry of Heart Failure (RECOLFACA). RECOLFACA registry enrolled 2528 adult patients with HF. A comparison was made between patients diagnosed with CCM and those diagnosed with other etiologies of HF. Eighty-eight patients (3.5%) present CCM diagnosis. The individuals diagnosed with both HF and CCM were notably younger in age, had less comorbidities, poorer functional class, and significantly inferior ejection fraction. Finally, the presence of CCM diagnosis was linked to a substantially elevated mortality risk throughout the follow-up period (HR 2.01; 95% CI, 1.01-4.00) according to a multivariate model adjusted. CCM represents an important etiology of HF in Colombia, drawing attention to a distinct clinical profile and a higher risk of mortality compared to other HF etiologies.

Comorbidity profile and outcomes in patients with chronic heart failure in a Latin American country: Insights from the Colombian heart failure registry (RECOLFACA).

BACKGROUND: Heart failure (HF) is usually accompanied by cardiovascular and non-cardiovascular comorbidities, which may significantly impact its prognosis. In this study we aimed to characterize the comorbidity profile and its impact in mortality in patients with HF diagnosis from the Colombian Heart Failure Registry (RECOLFACA). METHODS: RECOLFACA enrolled adult patients with HF diagnosis from 60 centers in Colombia during the period 2017-2019. The primary outcome was all-cause mortality. A Cox proportional hazards regression model was used to assess the impact of the comorbidities in mortality. A p-value of <0.05 was considered significant. RESULTS: From the total 2528 patients included in the registry, 2514 patients (58% males, mean age 68 years) had information regarding comorbidity diagnoses. 2321 patients (92.3%) reported at least one comorbidity. Arterial hypertension was the most frequent individual diagnosis (72%; n = 1811), followed by anemia (30.1%, n = 726). The most frequently observed coexisting comorbidities were coronary disease (CHD) with dyslipidemia, and chronic kidney disease (CKD) with type 2 Diabetes Mellitus (T2DM). Different patterns of comorbidity coexistence were observed when comparing HF patients by sex and left-ventricular ejection fraction (LVEF) classification. The only comorbidities that were significantly associated with mortality after multivariate adjustment were T2DM (HR 1.45. 95% CI 1.01-2.12), anemia (HR 1.48. 95% CI 1.02-2.16), and CHD (HR 1.59. 95% CI 1.09-2.33). CONCLUSION: Multiple comorbidities were frequently observed in the patients from the RECOLFACA. T2DM, anemia and CHD were significantly associated with a higher risk of mortality, highlighting the importance of promoting an optimal follow-up and control of these conditions.

Inhibition of pepper huasteco yellow veins virus by foliar application of ZnO nanoparticles in Capsicum annuum L.

The Pepper huasteco yellow vein virus (PHYVV) is an endemic geminivirus in Mexico causing partial or total losses in the pepper crop since the damage caused by the virus has not been fully controlled. In this work, we evaluated the effect of ZnO NPs (0, 50, 100, 150, and 200 mM) as a preventive (72 h before) and curative (72 h after) treatment of PHYVV infection in two jalapeño pepper varieties. In this study, we observed a decrease in symptoms, and it could be caused by an induction of the defense system in pepper plants and a direct action on PHYVV by foliar application of ZnO NPs. Our findings suggest that ZnO NP application significantly decreased the viral titer for both varieties at 200 mM by 15.11-fold. However, this effect was different depending on the timing of application and the variety of pepper. The greatest decrease in the viral titer in the preventive treatment in both varieties was at the concentration of 200 mM (1781.17 and 274.5 times, respectively). For curative treatment in cv. Don Pancho at the concentration of 200 mM (333.33 times) and cv. Don Benito at 100 mM (43.10 folds). compared to control. Furthermore, virus mobility was generally restricted for both varieties at 100 mM (15.13-fold) compared to the control. The results possibly delineated that ZnO NPs increased plant resistance possibly by increasing POD (2.08 and 0.25 times) and SOD (0.998 and 1.38) in cv. Don Pancho and cv. Don Benito, respectively. On the other hand, in cv. Don Pancho and cv. Don Benito presented a decrease in CAT (0.61 and 0.058) and PAL (0.78 and 0.77), respectively. Taken together, we provide the first evidence to demonstrate the effect of ZnO NPs on viral symptoms depending on the plan-virus-ZnO NP interaction.

Transcriptome analysis of symptomatic and recovered leaves of geminivirus-infected pepper (Capsicum annuum).

BACKGROUND: Geminiviruses are a large and important family of plant viruses that infect a wide range of crops throughout the world. The Begomovirus genus contains species that are transmitted by whiteflies and are distributed worldwide causing disease on an array of horticultural crops. Symptom remission, in which newly developed leaves of systemically infected plants exhibit a reduction in symptom severity (recovery), has been observed on pepper (Capsicum annuum) plants infected with Pepper golden mosaic virus (PepGMV). Previous studies have shown that transcriptional and post-transcriptional gene silencing mechanisms are involved in the reduction of viral nucleic acid concentration in recovered tissue. In this study, we employed deep transcriptome sequencing methods to assess transcriptional variation in healthy (mock), symptomatic, and recovered pepper leaves following PepGMV infection. RESULTS: Differential expression analyses of the pepper leaf transcriptome from symptomatic and recovered stages revealed a total of 309 differentially expressed genes between healthy (mock) and symptomatic or recovered tissues. Computational prediction of differential expression was validated using quantitative reverse-transcription PCR confirming the robustness of our bioinformatic methods. Within the set of differentially expressed genes associated with the recovery process were genes involved in defense responses including pathogenesis-related proteins, reactive oxygen species, systemic acquired resistance, jasmonic acid biosynthesis, and ethylene signaling. No major differences were found when compared the differentially expressed genes in symptomatic and recovered tissues. On the other hand, a set of genes with novel roles in defense responses was identified including genes involved in histone modification. This latter result suggested that post-transcriptional and transcriptional gene silencing may be one of the major mechanisms involved in the recovery process. Genes orthologous to the C. annuum proteins involved in the pepper-PepGMV recovery response were identified in both Solanum lycopersicum and Solanum tuberosum suggesting conservation of components of the viral recovery response in the Solanaceae. CONCLUSION: These data provide a valuable source of information for improving our understanding of the underlying molecular mechanisms by which pepper leaves become symptomless following infection with geminiviruses. The identification of orthologs for the majority of genes differentially expressed in recovered tissues in two major solanaceous crop species provides the basis for future comparative analyses of the viral recovery process across related taxa.

Characterization of Geminivirus resistance in an accession of Capsicum chinense Jacq.

Pepper golden mosaic virus (PepGMV) and Pepper huasteco yellow vein virus (PHYVV), members of the Geminiviridae family, are important pathogens of pepper (Capsicum annuum L.) and other solanaceous crops. Accession BG-3821 of C. chinense Jacq. was reported earlier as resistant to mixed infection with PepGMV and PHYVV. In this work, we characterized the Geminivirus resistance trait present in BG-3821. Segregation analysis suggested that resistance depends on two genes. Our data showed that PepGMV replication in protoplast of resistant plants is approximately 70% lower when compared with the levels observed in protoplasts from susceptible plants. Additionally, viral movement is less efficient in resistant plants. We also evaluated several characteristics commonly associated with systemic acquired resistance (SAR), which is a conserved defensive mechanism. The concentration of salicylic acid was higher in resistant plants inoculated with PepGMV than in susceptible plants. Marker genes for SAR were induced after inoculation with PepGMV in resistant leaves. Similarly, we found a higher accumulation of reactive oxygen species on resistant leaves compared with susceptible ones. A model for the mechanism acting in the Geminivirus resistance detected in BG-3821 is proposed. Finally, the importance of BG-3821 in Geminivirus resistance breeding programs is discussed.

Geminivirus mixed infection on pepper plants: synergistic interaction between PHYVV and PepGMV.

BACKGROUND: PHYVV and PepGMV are plant viruses reported in Mexico and Southern US as causal agents of an important pepper disease known as "rizado amarillo". Mixed infections with PHYVV and PepGMV have been reported in several hosts over a wide geographic area. Previous work suggested that these viruses might interact at the replication and/or movement level in a complex manner. The aim of present report was to study some aspects of a synergistic interaction between PHYVV and PepGMV in pepper plants. These include analyses of symptom severity, viral DNA concentration and tissue localization of both viruses in single and mixed infections. RESULTS: Mixed infections with PepGMV and PHYVV induced symptoms more severe than those observed in single viral infections. Whereas plants infected with either virus (single infection) presented a remission stage with a corresponding decrease in viral DNA levels, double-infected plants did not present symptom remission and both viral DNA concentrations dramatically increased. In situ hybridization experiments revealed that both viruses are restricted to the vascular tissue. Interestingly, the amount of viral DNA detected was higher in plants inoculated with PepGMV than that observed in PHYVV-infected plants. During mixed infections, the location of both viruses remained similar to the one observed in single infections, although the number of infected cells increases. Infections with the tripartite mixture PHYVV (A+B) + PepGMV A produced a similar synergistic infection to the one observed after inoculation with both full viruses. On the contrary, tripartite mixture PepGMV (A+B) + PHYVV A did not produce a synergistic interaction. In an attempt to study the contribution of individual genes to the synergism, several mutants of PHYVV or PepGMV were inoculated in combination with the corresponding wild type, second virus (wt PepGMV or wt PHYVV). All combinations tested resulted in synergistic infections, with exception of the TrAP mutant of PepGMV (PepGMV TrAP-) + PHYVV. CONCLUSION: In this report, we have demonstrated that synergistic interaction between PHYVV and PepGMV during a mixed infection is mainly due to an increased DNA concentration of both viruses, without any noticeable effect on the localization of either virus on infected plant tissue. Our results have shown that the viral component A from PepGMV is important for synergism during PHYVV-PepGMV mixed infections.

Validation of the spanish version of the Multiple Sclerosis International Quality of Life (Musiqol) questionnaire.

BACKGROUND: The Multiple Sclerosis International Quality Of Life (MusiQoL) questionnaire, a 31-item, multidimensional, self-administrated questionnaire that is available in 14 languages including Spanish, has been validated using a large international sample. We investigated the validity and reliability of the Spanish version of MusiQoL in Spain. METHODS: Consecutive patients with different types and severities of multiple sclerosis (MS) were recruited from 22 centres across Spain. All patients completed the MusiQoL questionnaire, the 36-Item Short Form (SF-36) health survey, and a symptoms checklist at baseline and 21 days later. External validity, internal consistency, reliability and reproducibility were tested. RESULTS: A total of 224 Spanish patients were evaluated. Dimensions of MusiQoL generally demonstrated a high internal consistency (Cronbach's alpha: 0.70-0.92 for all but two MusiQoL domain scores). External validity testing revealed that the MusiQoL index score correlated significantly with all SF-36 dimension scores (Pearson's correlation: 0.46-0.76), reproducibility was satisfactory (intraclass correlation coefficient: 0.60-0.91), acceptability was high, and the time taken to complete the 31-item questionnaire was reasonable (mean [standard deviation]: 9.8 [11.8] minutes). CONCLUSIONS: The Spanish version of the MusiQoL questionnaire appears to be a valid and reliable instrument for measuring quality of life in patients with MS in Spain and constitutes a useful instrument to measure health-related quality of life in the clinical setting.

RNA silencing against geminivirus: complementary action of posttranscriptional gene silencing and transcriptional gene silencing in host recovery.

RNA silencing in plants is a natural defense system mechanism against invading nucleic acids such as viruses. Geminiviruses, a family of plant viruses characterized by a circular, single-stranded DNA genome, are thought to be both inducers and targets of RNA silencing. Some natural geminivirus-host interactions lead to symptom remission or host recovery, a process commonly associated with RNA silencing-mediated defense. Pepper golden mosaic virus (PepGMV)-infected pepper plants show a recovery phenotype, which has been associated with the presence of virus-derived small RNAs. The results presented here suggest that PepGMV is targeted by both posttranscriptional and transcriptional gene silencing mechanisms. Two types of virus-related small interfering RNAs (siRNAs) were detected: siRNAs of 21 to 22 nucleotides (nt) in size that are related to the coding regions (Rep, TrAP, REn, and movement protein genes) and a 24-nt population primarily associated to the intergenic regions. Methylation levels of the PepGMV A intergenic and coat protein (CP) coding region were measured by a bisulfite sequencing approach. An inverse correlation was observed between the methylation status of the intergenic region and the concentration of viral DNA and symptom severity. The intergenic region also showed a methylation profile conserved in all times analyzed. The CP region, on the other hand, did not show a defined profile, and its methylation density was significantly lower than the one found on the intergenic region. The participation of both PTGS and TGS mechanisms in host recovery is discussed.

Superinfection by PHYVV Alters the Recovery Process in PepGMV-Infected Pepper Plants.

Geminiviruses are important plant pathogens that affect crops around the world. In some geminivirus-host interactions, infected plants show recovery, a phenomenon characterized by symptom disappearance in newly emerging leaves. In pepper-Pepper golden mosaic virus (PepGMV) interaction, the host recovery process involves a silencing mechanism that includes both post-transcriptional (PTGS) and transcriptional (TGS) gene silencing pathways. Under field conditions, PepGMV is frequently found in mixed infections with Pepper huasteco yellow vein virus (PHYVV), another bipartite begomovirus. Mixed infected plants generally show a synergetic phenomenon and do not present recovery. Little is known about the molecular mechanism of this interaction. In the present study, we explored the effect of superinfection by PHYVV on a PepGMV-infected pepper plant showing recovery. Superinfection with PHYVV led to (a) the appearance of severe symptoms, (b) an increase of the levels of PepGMV DNA accumulation, (c) a decrease of the relative methylation levels of PepGMV DNA, and (d) an increase of chromatin activation marks present in viral minichromosomes. Finally, using heterologous expression and silencing suppression reporter systems, we found that PHYVV REn presents TGS silencing suppressor activity, whereas similar experiments suggest that Rep might be involved in suppressing PTGS.

Sequence diversity on four ORFs of citrus tristeza virus correlates with pathogenicity.

The molecular characterization of isolates of citrus tristeza virus (CTV) from eight locations in Mexico was undertaken by analyzing five regions located at the opposite ends of the virus genome. Two regions have been previously used to study CTV variability (coat protein and p23), while the other three correspond to other genomic segments (p349-B, p349-C and p13). Our comparative nucleotide analyses included CTV sequences from different geographical origins already deposited in the GenBank databases. The largest nucleotide differences were located in two fragments located at the 5' end of the genome (p349-B and p349-C). Phylogenetic analyses on those five regions showed that the degree of nucleotide divergence among strains tended to correlate with their pathogenicity. Two main groups were defined: mild, with almost no noticeable effects on the indicator plants and severe, with drastic symptoms. Mild isolates clustered together in every analyzed ORF sharing a genetic distance below 0.022, in contrast with the severe isolates, which showed a more disperse distribution and a genetic distance of 0.276. Analyses of the p349-B and p349-C regions evidenced two lineages within the severe group: severe common subgroup (most of severe isolates) and severe divergent subgroup (T36-like isolates). This study represents the first attempt to analyze the genetic variability of CTV in Mexico by constructing phylogenetic trees based on new genomic regions that use group-specific nucleotide and amino acid sequences. These results may be useful to implement specific assays for strain discrimination. Moreover, it would be an excellent reference for the CTV situation in México to face the recent arrival of brown citrus aphid.

The infective cycle of Cabbage leaf curl virus (CaLCuV) is affected by CRUMPLED LEAF (CRL) gene in Arabidopsis thaliana.

BACKGROUND: Geminiviruses are single-stranded DNA viruses that cause serious crop losses worldwide. Successful infection by these pathogens depends extensively on virus-host intermolecular interactions that allow them to express their gene products, to replicate their genomes and to move to adjacent cells and throughout the plant. RESULTS: To identify host genes that show an altered regulation in response to Cabbage leaf curl virus (CaLCuV) infection, a screening of transposant Arabidopsis thaliana lines was carried out. Several genes were identified to be virus responsive and one, Crumpled leaf (CRL) gene, was selected for further characterization. CRL was previously reported by Asano et al., (2004) to affect the morphogenesis of all plant organs and the division of plastids. We report here that CRL expression, during CaLCuV infection, shows a short but strong induction at an early stage (3-5 days post inoculation, dpi). To study the role of CRL in CaLCuV infection, CRL over-expressing and silenced transgenic plants were generated. We compared the replication, movement and infectivity of CaLCuV in transgenic and wild type plants. CONCLUSION: Our results showed that CRL over-expressing plants showed an increased susceptibility to CaLCuV infection (as compared to wt plants) whereas CRL-silenced plants, on the contrary, presented a reduced susceptibility to viral infection. The possible role of CRL in the CaLCuV infection cycle is discussed.