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Genetic variation and trait plasticity in plant defence suppression
No full textAs plantas evoluíram um conjunto complexo de defesas, algumas delas induzíveis por herbivoria. Por sua vez, os herbívoros evoluíram para lidar com tais defesas, sendo que alguns conseguem suprimir as defesas do hospedeiro, geralmente através de efetores salivares. Apesar de crucial para a otimização do controlo de pragas, a variação genética e plasticidade da supressão de defesas é ainda pouco estudada. Assim sendo, esta tese teve como objetivo ampliar o conhecimento sobre a variabilidade genética e o impacto do ambiente na supressão de defesas. Para isso, estudei as pragas de tomateiros Tetranychus urticae e T. evansi, nas quais algumas populações conseguem suprimir defesas. Primeiro, estudei se a supressão de defesas é variável e como é que se correlaciona com a fecundidade de T. evansi. Observei que, apesar da supressão ser variável, a fecundidade não está correlacionada com os seus diferentes níveis. De seguida, avaliei se a supressão é comum em populações naturais de T. urticae obtidas de tomateiros. Descobri que esse era o caso, e que o gene effector 84 é altamente variável nesta espécie. De seguida, demonstrei que a supressão é mantida a uma temperatura elevada, apesar da expressão do effector 84 diminuir, sugerindo plasticidade. Para além disso, modelos de dinâmica populacional revelaram que uma temperatura elevada favorece ácaros T. urticae que suprimem defesas, excluindo ácaros que induzem defesas. Finalmente, observei que plantas infestadas com supressores não conseguem estabelecer defesas contra uma densidade alta de herbívoros, ao contrário de quando infestadas com indutores. Os meus resultados mostram que ambas as espécies têm variabilidade genética para a supressão de defesas e que a expressão do effector 84 é plástica com a temperatura. Esta tese oferece informações relevantes sobre como a supressão de defesas pode evoluir e ser mantida na natureza, uma vez que sugere que a adaptação ao hospedeiro e alterações na temperatura podem ser fatores importantes para a sua seleção, com implicações na gestão de pragas.Whereas many herbivores induce plant defences, many others can suppress them. Defence suppression promotes herbivore performance, and it is mediated via herbivore-derived compounds called effectors, often peptides produced in the salivary glands of herbivores. be Although crucial for optimizing pest control, the genetic variation and plasticity of defence suppression in herbivore communities is poorly understood. As such, this thesis aimed to increase knowledge on these. In this thesis, I studied the destructive pests Tetranychus urticae and T. evansi species, in which some populations can suppress tomato plant defences. First, I investigated if traits related to defence suppression in T. evansi are genetically variable and how this variation correlates with mite fecundity. I found that fecundity is a genetic variable for T. evansi but it is not affected by varying degrees of tomato JA defences. Then, we evaluated if defence suppression is a common trait among field T. urticae mites collected from tomato plants. I found this to be true and that the salivary effector 84 is highly variable in this species. Next, I showed that defence suppression is maintained at a high temperature, although the expression of effector 84 decreases, suggesting plasticity. Also, population dynamics models revealed that a high temperature may favour T. urticae mites that suppress defences, possibly displacing T. urticae inducer mites. Finally, I revealed plants infested with suppressor mites are compromised in mounting defences in a density-dependent manner, as opposed to inducer mites. My findings show that both mite species have genetic variation for defence suppression and that effector expression is plastic with temperature. This thesis also offers powerful insights into how defence suppression can evolve and be maintained in nature, as it suggests that host adaptation and high temperatures could be drivers for the selection of such a trait, with implications for crop pests management.Dutch Research Council através dos projetos ALWOP.283, NWO-VICI 1939
Genetic variation and trait plasticity in plant defence suppression
No full textAs plantas evoluíram um conjunto complexo de defesas, algumas delas induzíveis por herbivoria. Por sua vez, os herbívoros evoluíram para lidar com tais defesas, sendo que alguns conseguem suprimir as defesas do hospedeiro, geralmente através de efetores salivares. Apesar de crucial para a otimização do controlo de pragas, a variação genética e plasticidade da supressão de defesas é ainda pouco estudada. Assim sendo, esta tese teve como objetivo ampliar o conhecimento sobre a variabilidade genética e o impacto do ambiente na supressão de defesas. Para isso, estudei as pragas de tomateiros Tetranychus urticae e T. evansi, nas quais algumas populações conseguem suprimir defesas. Primeiro, estudei se a supressão de defesas é variável e como é que se correlaciona com a fecundidade de T. evansi. Observei que, apesar da supressão ser variável, a fecundidade não está correlacionada com os seus diferentes níveis. De seguida, avaliei se a supressão é comum em populações naturais de T. urticae obtidas de tomateiros. Descobri que esse era o caso, e que o gene effector 84 é altamente variável nesta espécie. De seguida, demonstrei que a supressão é mantida a uma temperatura elevada, apesar da expressão do effector 84 diminuir, sugerindo plasticidade. Para além disso, modelos de dinâmica populacional revelaram que uma temperatura elevada favorece ácaros T. urticae que suprimem defesas, excluindo ácaros que induzem defesas. Finalmente, observei que plantas infestadas com supressores não conseguem estabelecer defesas contra uma densidade alta de herbívoros, ao contrário de quando infestadas com indutores. Os meus resultados mostram que ambas as espécies têm variabilidade genética para a supressão de defesas e que a expressão do effector 84 é plástica com a temperatura. Esta tese oferece informações relevantes sobre como a supressão de defesas pode evoluir e ser mantida na natureza, uma vez que sugere que a adaptação ao hospedeiro e alterações na temperatura podem ser fatores importantes para a sua seleção, com implicações na gestão de pragas.Whereas many herbivores induce plant defences, many others can suppress them. Defence suppression promotes herbivore performance, and it is mediated via herbivore-derived compounds called effectors, often peptides produced in the salivary glands of herbivores. be Although crucial for optimizing pest control, the genetic variation and plasticity of defence suppression in herbivore communities is poorly understood. As such, this thesis aimed to increase knowledge on these. In this thesis, I studied the destructive pests Tetranychus urticae and T. evansi species, in which some populations can suppress tomato plant defences. First, I investigated if traits related to defence suppression in T. evansi are genetically variable and how this variation correlates with mite fecundity. I found that fecundity is a genetic variable for T. evansi but it is not affected by varying degrees of tomato JA defences. Then, we evaluated if defence suppression is a common trait among field T. urticae mites collected from tomato plants. I found this to be true and that the salivary effector 84 is highly variable in this species. Next, I showed that defence suppression is maintained at a high temperature, although the expression of effector 84 decreases, suggesting plasticity. Also, population dynamics models revealed that a high temperature may favour T. urticae mites that suppress defences, possibly displacing T. urticae inducer mites. Finally, I revealed plants infested with suppressor mites are compromised in mounting defences in a density-dependent manner, as opposed to inducer mites. My findings show that both mite species have genetic variation for defence suppression and that effector expression is plastic with temperature. This thesis also offers powerful insights into how defence suppression can evolve and be maintained in nature, as it suggests that host adaptation and high temperatures could be drivers for the selection of such a trait, with implications for crop pests management.Dutch Research Council através dos projetos ALWOP.283, NWO-VICI 1939
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Plant Responses to Phytophagous Mites/Thrips and Search for Resistance
No full textThis eBook is a collection of articles from a Frontiers Research Topic. Frontiers Research Topics are very popular trademarks of the Frontiers Journals Series: they are collections of at least ten articles, all centered on a particular subject. With their unique mix of varied contributions from Original Research to Review Articles, Frontiers Research Topics unify the most influential researchers, the latest key findings and historical advances in a hot research area! Find out more on how to host your own Frontiers Research Topic or contribute to one as an author by contacting the Frontiers Editorial Office: frontiersin.org/about/contac
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