The salicylic acid dependent and independent effects of NMD in plants

In eukaryotes, nonsense-mediated mRNA decay (NMD) targets aberrant and selected non-aberrant mRNAs for destruction. A recent screen for mRNAs showing increased abundance in Arabidopsis NMD-deficient mutants revealed that most are associated with the salicylic acid (SA)-mediated defense pathway. mRNAs with conserved peptide upstream open reading frames (CpuORFs or CuORFs) are hugely overrepresented among the smaller class of NMD-regulated transcripts not associated with SA. Here we show that the common phenotypes observed in Arabidopsis NMD mutants are SA-dependent, whereas the upregulation of CpuORF-containing transcripts in NMD mutants is independent of SA. We speculate that CpuORFs could allow the conditional targeting of mRNAs for destruction using the NMD pathway

A Role for Nonsense-Mediated mRNA Decay in Plants: Pathogen Responses Are Induced in Arabidopsis thaliana NMD Mutants

Nonsense-mediated mRNA decay (NMD) is a conserved mechanism that targets aberrant mRNAs for destruction. NMD has also been found to regulate the expression of large numbers of genes in diverse organisms, although the biological role for this is unclear and few evolutionarily conserved targets have been identified. Expression analyses of three Arabidopsis thaliana lines deficient in NMD reveal that the vast majority of NMD-targeted transcripts are associated with response to pathogens. Congruently, NMD mutants, in which these transcripts are elevated, confer partial resistance to Pseudomonas syringae. These findings suggest a biological rationale for the regulation of gene expression by NMD in plants and suggest that manipulation of NMD could offer a new approach for crop protection. Amongst the few non-pathogen responsive NMD-targeted genes, one potential NMD targeted signal, the evolutionarily conserved upstream open reading frame (CuORF), was found to be hugely over-represented, raising the possibility that this feature could be used to target specific physiological mRNAs for control by NMD

Transcriptional reprogramming underpins enhanced plant growth promotion by the biocontrol fungus Trichoderma hamatum GD12 during antagonistic interactions with Sclerotinia sclerotiorumin soil

The free-living soil fungus Trichoderma hamatum strain GD12 is notable amongst Trichoderma strains in both controlling plant diseases and in stimulating plant growth, a property enhanced during its antagonistic interactions with pathogens in soil. These attributes, alongside its markedly expanded genome and proteome compared to other biocontrol and plant growth promoting Trichoderma strains, imply a rich potential for sustainable alternatives to synthetic pesticides and fertilisers for controlling plant disease and increasing yields. The purpose of this study was to investigate the transcriptional responses of GD12 underpinning its biocontrol and plant growth promotion capabilities during antagonistic interactions with the pathogen Sclerotinia sclerotiorum in soil. Using an extensive mRNA-seq study capturing different time points during the pathogen-antagonist interaction in soil, we show that dynamic and biphasic signatures in the GD12 transcriptome underpin its biocontrol and plant (lettuce) growth promotional activities. Functional predictions of differentially expressed genes demonstrate the enrichment of transcripts encoding proteins involved in transportation and oxidation-reduction reactions during both processes and an over-representation of siderophores. We identify a biphasic response during biocontrol characterised by a significant induction of transcripts encoding small-secreted cysteine rich proteins, secondary metabolite producing gene clusters and genes unique to GD12. These data support the hypothesis that Sclerotinia biocontrol is mediated by the synthesis and secretion of antifungal compounds and that GD12's unique reservoir of uncharacterised genes is actively recruited during effective biological control of a plurivorous plant pathogen. This article is protected by copyright. All rights reserved

Transcriptional dynamics driving MAMP-triggered immunity and pathogen effector-mediated immunosuppression in Arabidopsis leaves following infection with Pseudomonas syringae pv tomato DC3000

Transcriptional reprogramming is integral to effective plant defense. Pathogen effectors act transcriptionally and posttranscriptionally to suppress defense responses. A major challenge to understanding disease and defense responses is discriminating between transcriptional reprogramming associated with microbial-associated molecular pattern (MAMP)-triggered immunity (MTI) and that orchestrated by effectors. A high-resolution time course of genome-wide expression changes following challenge with Pseudomonas syringae pv tomato DC3000 and the nonpathogenic mutant strain DC3000hrpA- allowed us to establish causal links between the activities of pathogen effectors and suppression of MTI and infer with high confidence a range of processes specifically targeted by effectors. Analysis of this information-rich data set with a range of computational tools provided insights into the earliest transcriptional events triggered by effector delivery, regulatory mechanisms recruited, and biological processes targeted. We show that the majority of genes contributing to disease or defense are induced within 6 h postinfection, significantly before pathogen multiplication. Suppression of chloroplast-associated genes is a rapid MAMP-triggered defense response, and suppression of genes involved in chromatin assembly and induction of ubiquitin-related genes coincide with pathogen-induced abscisic acid accumulation. Specific combinations of promoter motifs are engaged in fine-tuning the MTI response and active transcriptional suppression at specific promoter configurations by P. syringae

Negative symptoms and sex differences in first episode schizophrenia: What's their role in the functional outcome? A longitudinal study

Introduction: Negative symptoms (NS) include asociality, avolition, anhedonia, alogia, and blunted affect and are linked to poor prognosis. It has been suggested that they reflect two different factors: diminished expression (EXP) (blunted affect and alogia) and amotivation/pleasure (MAP) (anhedonia, avolition, asociality). The aim of this article was to examine potential sex differences among first-episode schizophrenia (FES) patients and analyze sex-related predictors of two NS symptoms factors (EXP and MAP) and functional outcome. Material and methods: Two hundred and twenty-three FES (71 females and 152 males) were included and evaluated at baseline, six-months and one-year. Repeated measures ANOVA was used to examine the effects of time and sex on NS and a multiple linear regression backward elimination was performed to predict NS factors (MAP-EXP) and functioning. Results: Females showed fewer NS (p = 0.031; Cohen's d = −0.312), especially those related to EXP (p = 0.024; Cohen's d = −0.326) rather than MAP (p = 0.086), than males. In both male and female group, worse premorbid adjustment and higher depressive symptoms made a significant contribution to the presence of higher deficits in EXP at one-year follow-up, while positive and depressive symptoms predicted alterations in MAP. Finally, in females, lower deficits in MAP and better premorbid adjustment predicted better functioning at one-year follow-up (R2 = 0.494; p < 0.001), while only higher deficits in MAP predicted worse functioning in males (R2 = 0.088; p = 0.012). Conclusions: Slightly sex differences have been found in this study. Our results lead us to consider that early interventions of NS, especially those focusing on motivation and pleasure symptoms, could improve functional outcomes

Influence of clinical and neurocognitive factors in psychosocial functioning after a first episode non-affective psychosis: differences between males and females

BackgroundDeficits in psychosocial functioning are present in the early stages of psychosis. Several factors, such as premorbid adjustment, neurocognitive performance, and cognitive reserve (CR), potentially influence functionality. Sex differences are observed in individuals with psychosis in multiple domains. Nonetheless, few studies have explored the predictive factors of poor functioning according to sex in first-episode psychosis (FEP). This study aimed to explore sex differences, examine changes, and identify predictors of functioning according to sex after onset.Materials and methodsThe initial sample comprised 588 individuals. However, only adults with non-affective FEP (n = 247, 161 males and 86 females) and healthy controls (n = 224, 142 males and 82 females) were included. A comprehensive assessment including functional, neuropsychological, and clinical scales was performed at baseline and at 2-year follow-up. A linear regression model was used to determine the predictors of functioning at 2-year follow-up.ResultsFEP improved their functionality at follow-up (67.4% of both males and females). In males, longer duration of untreated psychosis (β = 0.328, p = 0.003) and worse premorbid adjustment (β = 0.256, p = 0.023) were associated with impaired functioning at 2-year follow-up, while in females processing speed (β = 0.403, p = 0.003), executive function (β = 0.299, p = 0.020) and CR (β = −0.307, p = 0.012) were significantly associated with functioning.ConclusionOur data indicate that predictors of functioning at 2-year follow-up in the FEP group differ according to sex. Therefore, treatment and preventative efforts may be adjusted taking sex into account. Males may benefit from functional remediation at early stages. Conversely, in females, early interventions centered on CR enhancement and cognitive rehabilitation may be recommended

Expresión del gen de la fosfoenolpiruvato carboxiquinasa en el ciclo reproductivo mecanismo molecular de acción de la prolactina

Tesis doctoral inédita leida en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 17 de Noviembre de 1989

Expresion del gen de la fosfoenolpiruvato carboxiquinasa en el ciclo reproductivo Mecanismo molecular de accion de la prolactina

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai