Determinantes moleculares que participan en la interacción Fusarium oxysporum-tomate

En este trabajo se ha investigado sobre las bases moleculares que determinan la patogenicidad del hongo Fusarium oxysporum f. sp. lycopersici sobre plantas de tomate, estudiando particularmente la importancia de la detoxificación de compuestos antifúngicos producidos por las plantas de tomate, así como la relación entre la morfogénesis del patógeno y el desarrollo de la enfermedad. Las enzimas detoxificadoras de saponinas, producidas por hongos patógenos, están implicadas en el proceso de infección de sus plantas hospedadoras. F. oxysporum produce la enzima tomatinasa Tom1, que degrada la α-tomatina hasta derivados menos tóxicos. Para estudiar el papel del gen tom1 en la virulencia de F. oxysporum, se ha llevado a cabo la interrupción dirigida y la expresión constitutiva del gen en la estirpe silvestre del hongo. El proceso de infección de plantas de tomate inoculadas con transformantes del hongo con expresión constitutiva de la enzima Tom1 resulta en un incremento en el desarrollo de los síntomas de enfermedad. Por el contrario, las plantas de tomate infectadas con los mutantes deficientes en el gen muestran un retraso en el proceso de infección, lo que indica que Tom1, aunque no es esencial para la patogenicidad, es necesaria para la virulencia completa de F. oxysporum. La actividad tomatinasa total en las estirpes deficientes (Δtom1) se ve reducida solo un 25%, y se observa β2- tomatina como el mayor producto de hidrólisis de la saponina in vitro. El análisis in silico del genoma de F. oxysporum revela la existencia de cuatro posibles genes responsables de otras tantas tomatinasas con identidad a otras ortólogas de la familia 3 de glicosil hidrolasas. Los productos de estos genes podrían ser los responsables de la actividad tomatinasa reminiscente en los mutantes Δtom1, y por tanto, la detoxificación de la α-tomatina en F. oxysporum sería llevada a cabo por varias actividades enzimáticas independientes, lo que sugiere la importancia de estas enzimas durante el proceso de infección. En otro capítulo, se ha estudiado si la causa de la avirulencia del mutante ΔchsV de F. oxysporum, deficiente en un gen sintasa de quitina de..

The Fusarium oxysporum gnt2, Encoding a Putative NAcetylglucosamine Transferase, Is Involved in Cell Wall Architecture and Virulence

With the aim to decipher the molecular dialogue and cross talk between Fusarium oxysporum f.sp. lycopersci and its host during infection and to understand the molecular bases that govern fungal pathogenicity, we analysed genes presumably encoding N-acetylglucosaminyl transferases, involved in glycosylation of glycoproteins, glycolipids, proteoglycans or small molecule acceptors in other microorganisms. In silico analysis revealed the existence of seven putative N-glycosyl transferase encoding genes (named gnt) in F. oxysporum f.sp. lycopersici genome. gnt2 deletion mutants showed a dramatic reduction in virulence on both plant and animal hosts. Δgnt2 mutants had αalterations in cell wall properties related to terminal αor β-linked N-acetyl glucosamine. Mutant conidia and germlings also showed differences in structure and physicochemical surface properties. Conidial and hyphal aggregation differed between the mutant and wild type strains, in a pH independent manner. Transmission electron micrographs of germlings showed strong cell-to-cell adherence and the presence of an extracellular chemical matrix. Δgnt2 cell walls presented a significant reduction in N-linked oligosaccharides, suggesting the involvement of Gnt2 in N-glycosylation of cell wall proteins. Gnt2 was localized in Golgi-like sub-cellular compartments as determined by fluorescence microscopy of GFP::Gnt2 fusion protein after treatment with the antibiotic brefeldin A or by staining with fluorescent sphingolipid BODIPY-TR ceramide. Furthermore, density gradient ultracentrifugation allowed colocalization of GFP::Gnt2 fusion protein and Vps10p in subcellular fractions enriched in Golgi specific enzymatic activities. Our results suggest that N-acetylglucosaminyl transferases are key components for cell wall structure and influence interactions of F. oxysporum with both plant and animal hosts during pathogenicity

Análisis molecular de la patogénesis en Fusarium oxysporum

El proceso de infección del hongo Fusarium oxysporum es complejo y requiere algunos mecanismos bien regulados: 1) el reconocimiento de señales de la planta, 2) la adhesión a la superficie de la raíz y la diferenciación de hifas de penetración, 3) la invasión del córtex de la raíz y la degradación de barreras físicas hasta llegar al tejido vascular, 4) adaptación al entorno adverso del tejido vegetal, incluyendo la tolerancia a compuestos antifúngicos, 5) la proliferación de las hifas y producción de conidios en los vasos del xilema y, 6) la secreción de factores de virulencia tales como enzimas, péptidos o fitotoxina

Distinct colonization patterns and cDNA-AFLP transcriptome profiles in compatible and incompatible interactions between melon and different races of Fusarium oxysporum f. sp. melonis

Background: Fusarium oxysporum f. sp. melonis Snyd. & Hans. (FOM) causes Fusarium wilt, the most important infectious disease of melon (Cucumis melo L.). The four known races of this pathogen can be distinguished only by infection on appropriate cultivars. No molecular tools are available that can discriminate among the races, and the molecular basis of compatibility and disease progression are poorly understood. Resistance to races 1 and 2 is controlled by a single dominant gene, whereas only partial polygenic resistance to race 1,2 has been described. We carried out a large-scale cDNA-AFLP analysis to identify host genes potentially related to resistance and susceptibility as well as fungal genes associated with the infection process. At the same time, a systematic reisolation procedure on infected stems allowed us to monitor fungal colonization in compatible and incompatible host-pathogen combinations. Results: Melon plants (cv. Charentais Fom-2), which are susceptible to race 1,2 and resistant to race 1, were artificially infected with a race 1 strain of FOM or one of two race 1,2 w strains. Host colonization of stems was assessed at 1, 2, 4, 8, 14, 16, 18 and 21 days post inoculation (dpi), and the fungus was reisolated from infected plants. Markedly different colonization patterns were observed in compatible and incompatible host-pathogen combinations. Five time points from the symptomless early stage (2 dpi) to obvious wilting symptoms (21 dpi) were considered for cDNA-AFLP analysis. After successful sequencing of 627 transcript-derived fragments (TDFs) differentially expressed in infected plants, homology searching retrieved 305 melon transcripts, 195 FOM transcripts expressed in planta and 127 orphan TDFs. RNA samples from FOM colonies of the three strains grown in vitro were also included in the analysis to facilitate the detection of in planta-specific transcripts and to identify TDFs differentially expressed among races/strains. Conclusion: Our data suggest that resistance against FOM in melon involves only limited transcriptional changes, and that wilting symptoms could derive, at least partially, from an active plant response. We discuss the pathogen-derived transcripts expressed in planta during the infection process and potentially related to virulence functions, as well as transcripts that are differentially expressed between the two FOM races grown in vitro. These transcripts provide candidate sequences that can be further tested for their ability to distinguish between races. Sequence data from this article have been deposited in GenBank, Accession Numbers: HO867279-HO867981

Worldwide trends in underweight and obesity from 1990 to 2022: a pooled analysis of 3663 population-representative studies with 222 million children, adolescents, and adults

Background Underweight and obesity are associated with adverse health outcomes throughout the life course. We estimated the individual and combined prevalence of underweight or thinness and obesity, and their changes, from 1990 to 2022 for adults and school-aged children and adolescents in 200 countries and territories. Methods We used data from 3663 population-based studies with 222 million participants that measured height and weight in representative samples of the general population. We used a Bayesian hierarchical model to estimate trends in the prevalence of different BMI categories, separately for adults (age ≥20 years) and school-aged children and adolescents (age 5–19 years), from 1990 to 2022 for 200 countries and territories. For adults, we report the individual and combined prevalence of underweight (BMI <18·5 kg/m2) and obesity (BMI ≥30 kg/m2). For schoolaged children and adolescents, we report thinness (BMI <2 SD below the median of the WHO growth reference) and obesity (BMI >2 SD above the median). Findings From 1990 to 2022, the combined prevalence of underweight and obesity in adults decreased in 11 countries (6%) for women and 17 (9%) for men with a posterior probability of at least 0·80 that the observed changes were true decreases. The combined prevalence increased in 162 countries (81%) for women and 140 countries (70%) for men with a posterior probability of at least 0·80. In 2022, the combined prevalence of underweight and obesity was highest in island nations in the Caribbean and Polynesia and Micronesia, and countries in the Middle East and north Africa. Obesity prevalence was higher than underweight with posterior probability of at least 0·80 in 177 countries (89%) for women and 145 (73%) for men in 2022, whereas the converse was true in 16 countries (8%) for women, and 39 (20%) for men. From 1990 to 2022, the combined prevalence of thinness and obesity decreased among girls in five countries (3%) and among boys in 15 countries (8%) with a posterior probability of at least 0·80, and increased among girls in 140 countries (70%) and boys in 137 countries (69%) with a posterior probability of at least 0·80. The countries with highest combined prevalence of thinness and obesity in school-aged children and adolescents in 2022 were in Polynesia and Micronesia and the Caribbean for both sexes, and Chile and Qatar for boys. Combined prevalence was also high in some countries in south Asia, such as India and Pakistan, where thinness remained prevalent despite having declined. In 2022, obesity in school-aged children and adolescents was more prevalent than thinness with a posterior probability of at least 0·80 among girls in 133 countries (67%) and boys in 125 countries (63%), whereas the converse was true in 35 countries (18%) and 42 countries (21%), respectively. In almost all countries for both adults and school-aged children and adolescents, the increases in double burden were driven by increases in obesity, and decreases in double burden by declining underweight or thinness. Interpretation The combined burden of underweight and obesity has increased in most countries, driven by an increase in obesity, while underweight and thinness remain prevalent in south Asia and parts of Africa. A healthy nutrition transition that enhances access to nutritious foods is needed to address the remaining burden of underweight while curbing and reversing the increase in obesit

Breve informe por los herederos de Jayme Tribes y Pareja, vecinos de la Villa de Callosa de Segura, en el pleyto que siguen por esta Real Audiencia con los herederos de Don Juan Antonio Ornedal y Maza, Governador que fue de la Ciudad de Cartagena, sobre el riego de cierta heredad : Hecho, y seguida de los Autos.

Sobre el tít.: "[cristus] Jesus, Maria, Joseph, Joaquin, y Ana"Caplletra ornada al començament del textSign.: A-C2Text amb postil·les marginalsReclam