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FACTORS INVOLVED IN THE EVOLUTION OF BROAD BEAN WILT VIRUS 1 AND TOBACCO MOSAIC VIRUSFerriol Safont, Inmaculada 06 June 2012 (has links)
Los virus producen graves pérdidas económicas en la agricultura. Esta problemática es muy dinámica ya que cada año aparecen nuevas virosis y es frecuente los fenómenos de emergencia con una rápida expansión de los virus. El control de las enfermedades víricas resulta poco eficaz en muchos casos porque la población viral es capaz de evolucionar y superar dichas estrategias. Por ello es clave entender la dinámica de las poblaciones y los factores implicados en la evolución de los virus con respecto a distintos aspectos de su biología del ciclo viral: replicación, movimiento dentro de la planta, respuesta a los mecanismos de defensa de la planta, transmisión a otras plantas, etc.
El objetivo de esta tesis ha sido el estudio de los factores implicados en la evolución de dos virus que difieren en su variabilidad genética y gama de huéspedes: i) el Virus 1 del marchitamiento del haba (Broad bean wilt virus 1, BBWV-1), del género Fabavirus; y ii) el Virus del mosaico del tabaco (Tobacco mosaic virus, TMV) del género Tobamovirus.
Primero se han desarrollado una serie de herramientas metodológicas que han permitido la detección rápida de BBWV-1 mediante hibridación molecular de improntas, la detección y cuantificación de BBWV-1 y TMV y su diferenciación de otras virosis del mismo género mediante RT-PCR cuantitativa a tiempo real. Se ha llevado a cabo la construcción de clones de cDNA del genoma completo de BBWV-1 para obtener transcritos infecciosos que puedan ser usados para estudiar la biología molecular, evolución y epidemiología.
Una vez desarrollado esta metodología se ha usado para evaluar la eficacia biológica de BBWV-1 en el huésped y el efecto de algunos factores: concentración del inóculo, estado de desarrollo de la planta, tipo de huésped, aplicación de un activador de la defensa de la planta, y la infección con otro virus. Así mismo se han estudiado los factores relacionados con la eficacia biológica del virus durante su transmisión por pulgones: título viral / Ferriol Safont, I. (2012). FACTORS INVOLVED IN THE EVOLUTION OF BROAD BEAN WILT VIRUS 1 AND TOBACCO MOSAIC VIRUS [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16000
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Use of standard and setup of non conventional techniques for the elimination of viruses associated with Fig Mosaic Disease (FMD) in fig germplasm (Ficus carica L.)Yahyaoui, Emna 21 April 2017 (has links)
Abstract
Ficus carica L. is considered one of the oldest fruit trees in the Mediterranean basin and is widely grown and harvested for the consumption of its fruits dry and fresh. This species is affected by different virus diseases, especially by Fig mosaic disease (FMD), for which Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) and Fig fleck-associated virus (FFkaV) are associated. FMD is the most widespread disorder of this species, which represents a threat and a constraint for healthy fig production and germplasm exchange.
Thus, the objective of the present doctoral research was the establishment of an efficient and rapid in vitro F. carica propagation, sanitation and conservation of free-FMD plant material for future large-scale commercialization.
Initially, FMD-related viruses distribution was screened within the different fig plant organs (buds, leaves, syconia and seeds) of 14 Mediterranean genotypes (Palazzo, Severoni precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto nero, Catalanisca, Houmairi, Triboiti and Turca 'Serilop') which were utilized afterward as in vitro plant source material. RT-PCR assays revealed that all the aforementioned viruses were present without any exception in seeds, whereas only 4 viruses (FBV, FFkaV, FLMaV-1 and FMV) were detected in buds, leaves and syconia with highly variable infection rates.
Moreover, encapsulation technology proved to be a powerful multiplication technique to sustain standard fig tissue culture protocol for three cultivars (Catalanisca, Palazzo and Bifera) and it gave high, almost similar, viability, regrowth and conversion rates. Microcutting rooting in one-step was achieved and conversion rate was comparable for the three cultivars.
Furthermore, in order to eliminate FMD associated viruses, with the exception of FBV-1 which resisted to all the sanitation attempts, Caulogenesis and Meristem Tip Culture Protected by the Synthetic Seeds technique (MTC-SS) gave the best sanitation rates.
Finally, F. carica (cv. Houmairi) artificial seeds conservation, for final delivery, was achieved. A high viability and moderate regrowth rates were registered with a lesser conversion rate strictly related to the plant growth regulators (PGRs) used.
Keywords: Fig, mosaic, RT-PCR, virus distribution, cytokinins, encapsulation, micropropagation, synthetic seed. / Resumen
La higuera (Ficus carica L.) es considerada como uno de de los árboles frutales más antiguos de la cuenca mediterránea y es ampliamente cultivado y cosechado para el consumo de sus frutos tanto secos como en fresco. Esta especie se ve afectada por diversas enfermedades virales, especialmente por la denominada "Fig mosaic disease" (FMD) asociada actualemnte a los virus: Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) y Fig fleck-associated virus (FFkaV). Esta enfermedad representa una amenaza y un obstáculo para la producción de higos y el intercambio de germoplasma.
El principal objetivo del presente trabajo fue establecer un método de propagación de higuera in vitro para el saneamiento y la conservación de material vegetal libre de FMD para su posterior comercialización.
Inicialmente, se estudió la distribución de los virus implicados en la enfermedad en diversos órganos de 14 genotipos de F. carica (Palazzo, Severoni precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto nero, Catalanisca, Houmairi, Triboiti y Turca 'Serilop'), los cuales fueron utilizados posteriormente como fuente material vegetal in vitro. Los resultados obtenidos mediante RT-PCR revelaron que todos los virus mencionados estaban presentes sin excepción en las semillas, mientras que sólo cuatro de ellos (FBV, FFkaV, FLMaV-1 y FMV) fueron en brotes, hojas y siconios con tasas de infección variables.
Además, la tecnología de encapsulación demostró ser una técnica de multiplicación eficaz para poder aplicar el protocolo estándar de cultivo de tejidos de higo para tres cultivares (Catalanisca, Palazzo y Bifera) dando altas tasas de viabilidad, rebrote y conversión. Se logró el enraizamiento de microcortes en un solo paso y el índice de conversión fue comparable para los tres cultivares.
La callogénesis y el culñtivo de meristemos con la técnica de la semilla sintética (MTC-SS) fueron las técnicas que proporcionaron mayores tasas de desinfección para los virus estudiados a excepción de con FBV-1, entidad viral que no fue eliminada con ninguna de las técnicas ensayadas.
Por último, se logró la conservación de las semillas artificiales de higuera (cv Houmairi), registrándose una alta viabilidad y tasas de rebrote moderadas con un menor grado de conversión estrictamente relacionado con hormonas utilizadas.
Palabras clave: Higuera, mosaico, RT-PCR, la distribución de los virus, hormonas, encapsulación, micropropagación, y la semilla sintética. / Resum
La figuera (Ficus carica L.) és considerada un dels arbres fruiters més antics de la conca mediterrània i és àmpliament conreat i collit per al seu consum fresc i sec. Les malalties virals, especialment "Fig mosaic disease" (FMD), associada amb els viruses: Fig leaf mottle-associated virus 1 (FLMaV-1), Fig leaf mottle-associated virus 2 (FLMaV-2), Fig mild mottling-associated virus (FMMaV), Fig mosaic virus (FMV), Fig latent virus 1 (FLV-1), Fig badnavirus 1 (FBV-1) i Fig fleck-associated virus (FFkaV). Esta malaltia representa una amenaça per a la producció de figues i l'intercanvi de germoplasma.
El principal objectiu d'aquest treball va ser estableixerun mètode de propagació de figuera in vitro per al sanejament i la conservació de material lliure de FMD per a su posterior commercialització. Inicialment, es va estudiar la distribució dels virus associats a FMD en diversos òrgans en 14 genotips de F. carica (Palazzo, Severoni Precoce, Bianca, Pilusedda, Dottato bianco, Bifera, Zidi, Baiyadi, Biancu, Brogiotto diners, Catalanisca, Houmairi, Triboiti i Turca 'Serilop'), els quals van ser utilitzats posteriorment com a font de material vegetal in vitro.
Els resultats obtinguts del anàlisis realitzats per RT-PCR van revelar que tots els virus eren presents sense excepció en les llavors, mentre que només quatre virus (FBV, FFkaV, FLMaV-1 i FMV) van ser detectats en brots, fulles i siconis amb taxes d'infecció variables.
A més, la tecnologia d'encapsulació va demostrar ser una tècnica de multiplicació eficaç per poder aplicar el protocol estàndard de cultiu de teixits de figa per a tres cultivars (Catalanisca, Palazzo i Bifera) donant taxesadequades de viabilitat, rebrot i conversió. Es va aconseguir l'arrelament de microtalls en un sol pas i l'índex de conversió va ser comparable per als tres cultivars.
La calogènesi i el cultiu de meristems protegits per llavors sintètiques (MTC-SS)van ser les tècniques que proporcionarem millores tases de desinfecció per als virus estudiats amb l'excepció de FBV-1 que es va resistir a tots els mètodes de sanejament.
Finalment, es va aconseguir la conservació de la llavors artificials de figuera (cv. Houmairi), registrant-ne una alta viabilitat i taxes de rebrot moderades amb un menor grau de conversió estrictament relacionat amb hormones utilitzades.
Paraules clau: Figuera, mosaic, RT-PCR, la distribució dels virus, hormones, encapsulació, micropropagació, i la llavor sintètica. / Yahyaoui, E. (2017). Use of standard and setup of non conventional techniques for the elimination of viruses associated with Fig Mosaic Disease (FMD) in fig germplasm (Ficus carica L.) [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79876
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Exploiting Hardware-Accelerated Ray Tracing for Spatial Tree AlgorithmsVani Nagarajan (20380254) 07 December 2024 (has links)
<p dir="ltr">General Purpose computing on Graphical Processing Units (GPGPU) has resulted in un-precedented levels of speedup over its CPU counterparts, allowing programmers to harness the computational power of GPU shader cores to accelerate other computing applications. But this style of acceleration is best suited for regular computations (e.g., linear algebra). Recent GPUs feature new Ray Tracing (RT) cores that instead speed up the irregular process of ray tracing using Bounding Volume Hierarchies. While these cores seem limited in functionality, recent works have shown that it is possible to leverage the acceleration of RT cores by restructuring irregular problems to resemble ray tracing queries. In this dissertation, we explore leveraging RT cores to accelerate general-purpose computations. We introduce RT-accelerated variations of algorithms and suggest enhancements for current implementations. First, we propose RT-DBSCAN, the first RT-accelerated DBSCAN implementation. We use RT cores to accelerate Density-Based Clustering of Applications with Noise (DBSCAN) by translating fixed-radius nearest neighbor queries to ray tracing queries. As the neighbor queries are the main performance bottleneck in DBSCAN, we find that leveraging the RT hardware results in speedups between 1.3x to 4x over current state-of-the-art, GPU-based DBSCAN implementations. Though the existing translation of nearest neighbor search (NNS) problems to ray tracing queries has been shown to be effective, it imposes a constraint on the search space for neighbors. Due to this, we can only use RT cores to accelerate fixed-radius NNS, which requires the user to set a search radius a priori and hence can miss neighbors. To remedy this, we propose TrueKNN, the first unbounded RT-accelerated neighbor search. We solve the k-nearest neighbor search problem by adopting an iterative approach where we incrementally grow the search space until all points have found their k neighbors. We show that our approach is orders of magnitude faster than existing approaches and can even be used to accelerate fixed-radius neighbor searches. The n-body problem involves calculating the effect of bodies on each other. n-body simulations are ubiquitous in the fields of physics and astronomy and notoriously computationally expensive. The naïve algorithm for n-body simulations has the prohibiting O(n2) time complexity. Reducing the time complexity to O(n · lg(n)), the tree-based Barnes-Hut algorithm approximates the effect of bodies beyond a certain threshold distance. In tree-based NNS, computation is restricted solely to the leaf nodes of the tree, whereas Barnes-Hut requires computation to occur at both the leaf and internal nodes of the tree. In this work, we reformulate the Barnes-Hut algorithm as a ray-tracing problem and implement it with NVIDIA OptiX. Our evaluation shows that the resulting system, RT-BarnesHut, outperforms current state-of-the-art GPU-based implementations.</p>
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Improved detection of Sugarcane yellow leaf virus using a real- time fluorescent (TaqMan) RT-PCR assay.Korimbocus, J., Coates, David, Barker, I., Boonham, N. January 2002 (has links)
No / Yellow leaf syndrome (YLS) of sugarcane has been associated with Sugarcane yellow leaf virus (ScYLV) and has been reported from most sugarcane growing countries around the world. As sugarcane is vegetatively propagated, it is important to use effective and sensitive detection methods to screen new propagating material. Virus detection in symptomatic tissue is currently achieved using enzyme linked immunosorbent assay (ELISA), tissue blot immunoassay (TBIA) or a conventional RT-PCR based assay. This paper reports the development of an improved assay based on multiplex real-time fluorescent RT-PCR. The new assay is 100-fold more sensitive than conventional RT-PCR, and incorporates a novel `RNA specific¿ internal positive control (based around the intron of the caffeic acid 3-o-methyltransferase gene) to guard against false negative results. The paper also describes the comparison of eight RNA extraction methods for sugarcane tissue giving a number of alternatives for different laboratory situations. The sensitivity of this assay has allowed the detection of ScYLV in many samples that were thought to be healthy following conventional testing (RT-PCR, ELISA or TBIA). The detection of ScYLV using this TaqMan assay can be applied to the production of ScYLV-free plants and prevents its spread through the propagation material.
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Study of cox1 trans-splicing in Diplonema papillatum mitochondriaYan, Yifei 07 1900 (has links)
Diplonema papillatum est un organisme unicellulaire qui vit dans l’océan. Son génome mitochondrial possède une caractéristique spéciale: tous les gènes sont brisés en de multiples fragments qui s’appellent modules. Chaque module est codé par un chromosome différent. L’expression d’un gène exige des épissages-en-trans qui assemblent un ARN messager complet à partir de tous les modules du gène. Nous avons précédemment montré que le gène cox1 est encodé dans neuf modules avec six Us non encodés entre le module 4 et le module 5 de l’ARN messager mature [1]. Nous n’avons identifié aucune séquence consensus connue de site d’épissage près des modules. Nous spéculons qu’un ARN guide (gRNA) a dirigé l’épissage-en-trans du gène cox1 par un mécanisme qui est semblable à l’édition d’ARN par l’insertion/la suppression des Us chez les kinétoplastides, le groupe sœur des diplonémides. Nous avons trouvé que les six Us sont ajoutés au bout 3’ de l’ARN d’une façon semblable à ceux ajoutés par le TUTase lors de l’édition de l’insertion des Us chez les kinétoplastides. Nous avons construit des profils de gRNA de l’épissage-en-trans avec les expressions régulières basé sur notre connaissance des gRNAs dans l’édition d’ARN chez les kinétoplastides. Selon la complémentarité partielle entre le gRNA et les deux modules adjacents, nous avons généré des amorces pour RT-PCR visant à détecter des séquences qui sont assorties à un des profils de gRNA. Une expérience pilote in vitro n’a pas permis de reconstituer l’épissage-en-trans des modules 3, 4, et 5, suggérant que nous devons améliorer nos techniques. / Diplonema papillatum is a single cellular organism that lives in the ocean. Its mitochondrial genome possesses a special feature: all genes are fragmented in multiple pieces that are called modules and each module is encoded by a different chromosome. Expression of a gene requires trans-splicing that successfully assemble a full-length mRNA from all modules of the gene. It was previously shown that the cox1 gene is encoded in nine modules that are all located on different chromosomes; moreover, a stretch of six non-encoded Us exist between Module 4 and 5 in the mature mRNA [1]. No consensus sequence of known splicing sites was identified near the modules. We speculate that trans-splicing of the cox1 gene is directed by guide RNAs (gRNAs) via a mechanism that is similar to U-insertion/deletion editing in kinetoplastids, the sister group of diplonemids. We have detected populations of small RNA molecules that could come from mitochondrial. We found that the six Us were added to the 3’ end of Module 4 in a similar way to the Us added by the TUTase in kinetoplastid U-insertional editing. Sequence profiles of possible trans-splicing gRNAs were constructed in regular expressions based on our knowledge of known gRNAs in kinetoplastid RNA editing. According to the complementarity between the gRNA and the two adjacent modules, primers were designed for RT-PCR that aims to detect gRNA sequences. Among the results, we identified sequences that match or partially match the gRNA profiles. A pilot in vitro assay did not reconstitute trans-splicing of module 3, 4 and 5, suggesting that further technical improvements are needed.
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Role proteinů tepelného šoku v patogenezi placentární insuficience. / The Role of Heat Shock Proteins in Pathogenesis of Placental InsufficinecySlabá, Kristýna January 2015 (has links)
Heat shock proteins (Hsp) are highly conserved proteins that are part of the universal stress response of the cell. Their main function is to protect cells against structural and functional damage. Organisms exposed to different forms of stress, such as e.g. a lack of nutrients or water, hypoxia, infection or inflammation, demonstrated an increased gene expression of these proteins. Pregnancy complications cause stress conditions for maternal and fetal organism, which may result in an increased gene expression of Hsp. In my thesis, I examined the concentration of extracellular mRNA for five different heat shock proteins (Hsp27, Hsp60, Hsp70, Hsp90, HspBP1) in the plasma of pregnant women and wheather this concentration is affected by possible pregnancy complications (preeclampsia, fetal growth restriction and gestational hypertension). I also investigated a possible correlation between mRNA plasma concentration for Hsp and pulsatility index values (PI) obtained by Doppler ultrasound. This research should help to invent a new predictive method for pregnancy complications, based on a detection of specific biomarkers in the first trimester of pregnancy. The research was conducted on plasma samples obtained from peripheral blood of pregnant women, whose collection was performed during clinical manifestations of...
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Screening kandidátních genů u karcinomu prostaty a močového měchýře / Candidate genes screening for prostate cancerSemaneková, Viera January 2013 (has links)
Prostate carcinoma is considered to be one of the main medical problem in male population. Prostate carcinoma is the most frequently diagnosed malignancy in men and the death rate has the second position within all diagnosed malignancies in Czech Republic (ÚZIS). There is only one reliable diagnostic tool: PSA (prostate specific antigen). Level of PSA is often elevated in men with prostate carcinoma. This diploma thesis is focused on study of changes in gene expression in prostate carcinoma. Three candidate genes were analyzed: VCL (vinculin), SHB (Src homology 2 binding protein) and OCT3 (organic cation transporter 3). According to recent publications, these genes are related to tumor progression and they could have prognostic significance. In this thesis the following methodological approaches were used: 82 prostatic specimens were collected from patients and mRNA was isolated from these specimens; then RT-PCR was used to obtain cDNA, fragments were detected by electrophoresis. At the end statistical methods were used for evaluation. Relative expression of the genes in prostate carcinoma tissue was compared to relative expression of the genes in BPH (benign prostatic neoplasia) tissue. Results showed higher expression of genes SHB and OCT3 in prostate carcinoma tissue in compariscon to BPH...
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Exprese kandidátních genů karcinomu prostaty / Expression of candidate genes for prostate cancerKrupicová, Daniela January 2013 (has links)
4 Abstract Prostate cancer is one of the major medical problems within the male population in the Czech Republic and in the world. It is on second place among cancer illnesses with respect to mortality in czech male population. Its incidence strongly increases with age. Prostate cells have a unique ability to accumulate zinc in high concentrations compared to other tissues of human body. It is necessary for the proper physiological function of the prostate. There was detected loss of this accumulation ability in prostate cancer cells, which seems to be a condition to carcinogenesis in prostate cells. In this thesis was investigated the expression of four genes involved in the maintenance of homeostasis of zinc in prostate cells. Genes ZIP1 and ZIP7 encode zinc transporters, genes MT1-F and MT2 encode metallothioneins. There was collected 90 biopsy specimens from patients with prostate cancer or with benign prostatic hyperplasia. mRNA was isolated from these samples, cDNA was obtained by RT-PCR. This cDNA was detected by gel electrophoresis and the results were statistically evaluated. Several correlations was found between gene expression and the clinical data of patients. The most important result, there was found lower levels of expression of genes MT1- F and ZIP1 in samples of patients with cancer...
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Histoire évolutive des Poaceae et relations avec la communauté bactérienne rhizosphérique / Evolutive history of Poaceae and relationship with bacterial community in the rhizosphereBouffaud, Marie-Lara 12 December 2011 (has links)
Depuis l’apparition de la vie sur terre, les pressions de sélection liées aux interactions biotiques et abiotiques ont généré une forte diversité des formes de vie. Ainsi, chaque espèce eucaryote coévolue avec sa communauté microbienne associée. Dans le cas des plantes, la diversité génétique se traduit au niveau de multiples traits phénotypiques (exsudation de substrats carbonés, architecture racinaire, densité et aération du sol, acidification, etc.) susceptibles d’influer sur les interactions avec les populations microbiennes du sol, et donc sur la composition et le fonctionnement de la communauté microbienne rhizosphérique. Notre hypothèse est que les différences entre communautés bactériennes rhizosphériques sont proportionnelles aux distances évolutives entre partenaires végétaux. L’objectif de cette thèse était donc de déterminer l’importance, dans le cas des Poacées et notamment du maïs, de l’histoire évolutive de la plante dans la capacité de sélection des communautés bactériennes de la rhizosphère. Les analyses faites à l’aide d’une puce à ADN taxonomique 16S indiquent que la composition de la communauté rhizobactérienne dépend du groupe génétique de maïs mais n’est pas liée aux marqueurs microsatellites de diversité du maïs. Par contre, à l’échelle des Poacées, une corrélation a été trouvée entre la phylogénie végétale et la composition de la communauté bactérienne (voire la prévalence de taxons bactériens particuliers). Cette corrélation n’était pas significative quand l’étude était limitée à l’effectif, le niveau de transcription de nifH ou la diversité du groupe fonctionnel des bactéries fixatrices d’azote. En conclusion, l’histoire évolutive du partenaire végétal à l’échelle des Poacées (mais pas à celle du maïs) est un facteur conditionnant les interactions avec les groupes bactériens taxonomiques (mais pas nécessairement fonctionnels) de la rhizosphère / Since the emergence of life on earth, the selection pressures related to biotic and abiotic interactions generated a high diversity of life forms. Thus, each eukaryotic species co-evolved with its associated microbial community. In the case of plants, genetic diversity is reflected in many phenotypic traits (exudation of carbon substrates, root architecture, soil density, aeration, acidification, etc.), and may influence interactions with soil microbial populations and hence the composition and functioning of the rhizosphere microbial community. Our hypothesis is that the differences between rhizosphere bacterial communities are proportional to evolutionary distances between plants partners. The objective of this thesis was to determine the importance, in the case of Poaceae and in particular of maize, of the evolutionary history of plant in the selection of bacterial communities in the rhizosphere. Analyses performed using a 16S taxonomic microarray indicated that the composition of the rhizobacterial community depends on the genetic group of maize but is not linked to microsatellite diversity of maize. Conversely, across the Poaceae, a correlation was found between plant phylogeny and the composition of the bacterial community (and the prevalence of specific bacterial taxa). This correlation was not significant when the study was limited to the size, the level of transcription or nifH diversity of the functional group of nitrogen-fixing bacteria. In conclusion, the evolutionary history of the plant partner across the Poaceae (but not maize) is a factor conditioning interactions with bacterial taxonomic groups (but not necessarily functional groups) in the rhizosphere
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Estudo da interação entre a broca da cana-de-açúcar Diatraea saccharalis (Lepidoptera: Crambidae) e fungos oportunistas Colletotrichum falcatum e Fusarium verticillioides / Study of sugarcane borer Diatraea saccharalis (Lepidoptera: Crambidae) and opportunist fungi Colletotrichum falcatum and Fusarium verticillioides interactionGallan, Diego Zanardo 26 April 2019 (has links)
Em cana-de-açúcar, a colonização do caule por fungos oportunistas, como Fusarium verticillioides e Colletotrichum falcatum, está diretamente ligada ao ataque da lagarta Diatraea saccharalis (Lepidoptera: Crambidae). Duas proteínas, SUGARWIN1 e SUGARWIN2 são produzidas em cana-de-açúcar, em resposta ao dano mecânico e ao ataque de D. saccharalis, porém estas proteínas não afetam o inseto, e sim ocasionam alterações fisiológicas e morfológicas em F. verticillioides e C. falcatum, ocasionando a morte destes fungos por apoptose. Dietas artificiais suplementadas com estes fungos oportunistas ocasionaram o ganho de peso da D. saccharalis. Esses dados indicam uma interação mais íntima entre o inseto e estes patógenos de cana, sendo que, neste estudo procuramos identificar relações simbióticas entre os indivíduos, analisando se a forma de transmissão desses fungos é mediado pela D. saccharalis. Os resultados mostraram a presença do F. verticillioides em todas as fases de desenvolvimento da D. saccharalis após contato com o fungo, ou seja, depois de se alimentarem em dieta suplementada por F. verticillioides no 4º instar, permaneceram infectadas pelo fungo ao longo de toda a fase pupal e adulta, em ambos os sexos. Além disso, o F. verticillioides foi transmitido para os descendentes de D. saccharalis, sendo que o fungo foi detectado nos ovos, ou seja, um caso original de transmissão vertical. Por meio de microscopia, também foi possível verificar a alta intensidade de F. verticillioides no interior do intestino de lagartas. Estes dados inferem em uma relação simbiótica entre F. verticillioides e D. saccharalis, onde o simbionte é transferido verticalmente para as gerações subsequentes. As respostas obtidas com o fungo C. falcatum diferiram daquelas obtidas com F. verticillioides, uma vez que não se detectou a presença do fungo a partir da fase pupal. Neste caso, a relação de simbiose entre o fungo e o inseto pode resultar em uma transmissão horizontal. Com este estudo foi possível identificar diferentes formas de transmissão por D. saccharalis para dois fungos envolvidos em podridão de colmo em cana-de-açúcar. Estes dados mudam a forma como é vista a transmissão de F. verticillioides por D. saccharalis em cana-de-açúcar, podendo influenciar a forma de manejo da podridão de Fusarium e da broca nos canaviais. / In sugarcane, stem colonization by opportunistic fungi, such as Fusarium verticillioides and Colletotrichum falcatum, is directly linked to the attack of Diatraea saccharalis (Lepidoptera: Crambidae) caterpillar. Two proteins, SUGARWIN1 and SUGARWIN2 are produced in sugarcane, in response to mechanical damage and attack of D. saccharalis, however these proteins do not affect the insect, but cause physiological and morphological changes in F. verticillioides and C. falcatum, causing the death of these fungi by apoptosis. Artificial diets supplemented with these opportunistic fungi caused the weight gain of D. saccharalis. These data indicate a more intimate interaction between the insect and the sugarcane pathogens. In this study, we sought to identify symbiotic relationship among individuals, analyzing whether the transmission of these fungi is mediated by D. saccharalis. The results showed the presence of F. verticillioides in all stages of D. saccharalis development after contact with the fungus, in the 4th instar. The caterpillars remained infect by the fungus throughout the pupal and adult phase, in both sexes. In addition, F. verticillioides was transmitted to D. saccharalis offspring, being detected in eggs, an original case of vertical transmission. Through the microscopy results, it was also possible to verify the high intensity of F. verticillioides inside the intestines of caterpillar. These data infer in a symbiotic relationship between F. verticillioides and D. saccharalis, where the symbiont is transferred vertically to the offspring. The responses obtained with C. falcatum differed from those obtained with F. verticillioides, since the presence of the fungus was not detected from the pupal phase. In this case, the symbiont relationship between fungus and insect can result in a horizontal transmission. With this study was possible to identify different forms of fungi transmission by D. saccharalis. These data change the way the transmission of F. verticillioides by D. saccharalis in sugarcane is viewed, and may influence the management of Fusarium rot and sugarcane borer attack in sugarcane.
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