ITQB: PCBTH - PhD Theses
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- A molecular approach to understand embryo development to seed filling in common bean (Phaseolus vulgaris L.)Publication . Lopes, Cláudia Isabel Rodrigues; Fevereiro, Pedro; Araújo, Susana"Phaseolus vulgaris L. (common bean) is one of the most consumed grain legumes worldwide. It is rich in proteins, carbohydrates, fiber, iron and essential micronutrients. Its agronomic significance extends beyond nutrition, as P. vulgaris contributes to sustainable agriculture through its nitrogen-fixing capabilities, improving soil fertility and reducing the need for synthetic fertilizers. (...)"
- Deciphering seed development mechanisms in Phaseolus vulgaris L.Publication . Parreira, J. R.; Fevereiro, Pedro; Araújo, Susana"Seed development is one of the most relevant developmental processes in seed-producing crops. Seeds are essential to plants since they assure the next generation and the survival of the plant species. Nevertheless, they are important as food or feed for humans and animals, as a source of nutrients, playing important agronomic and socio-economic roles. Seed development is a complex developmental process that involves numerous molecular players and complex regulatory networks that is still poorly addressed in the literature, particularly for Legumes. This gap of knowledge was addressed within the scope of this thesis."
- Genomic approaches to understand the genetic response to Phytophthora cinnamomi Rands in Castanea spp.Publication . Santos, Carmen Sofia Pedro dos; Fevereiro, Pedro; Costa, Rita Lourenço"Chestnut is a multipurpose tree, having important economic, ecological and scientific values. European chestnut (Castanea sativa) produces the most appreciated and valued nuts worldwide. However, chestnut orchards and forests are declining in Europe due to introduced diseases and pests, mainly the ink disease. This destructive disease is caused by the widespread soil-borne oomycete Phytophthora cinnamomi. P. cinnamomi infection occurs in roots causing root rot and dieback in susceptible species. Nevertheless, the susceptible level varies among chestnut species, being the Asian species the most resistant to the pathogen.(...)"
- Critical Players and Gene Expression Regulation in Eucalyptus XylogenesisPublication . Carocha, Victor João Martins Taveira; Fevereiro, Pedro; Paiva, Jorge; Pettenati, JacquelineSecondary xylem, commonly known as wood, is essentially formed by highly lignified secondary cell walls of both fibres and vessels. The process of formation of secondary xylem is also termed xylogenesis. Secondary xylem derives from the vascular cambium, whose dividing cells undergo irreversible differentiation, under a strict temporal and spatial control.(...)
- Salinity adaptation in Tunisian and Portuguese Medicago truncatula populationsPublication . Cordeiro, Matilde de Vasconcelos Manso Ataíde; Fevereiro, Pedro; Cook, DouglasWorldwide, salinity is a major constraint for plant growth and reproduction of both crop and wild species. Soil salinization is expected to aggravate, particularly in a scenario of climate change. There is a need to implement sustainable, long-term measurements to guarantee the global agricultural production levels necessary for food security. The study of wild populations that are viable and fertile in saline habitats has the potential to reveal adaptive mechanisms bringing new insights for crop improvement. Here, methods of molecular biology and ecology are used to investigate the genes and traits responsible for salinity adaptation in natural populations of the model legume Medicago truncatula.(...)
- Effectiveness of Selection Methods for Improvement of Portuguese Maize (Zea mays L.)Publication . Moreira, Pedro Manuel Reis Mendes; Fevereiro, Pedro; Patto, Carlota VazSince its introduction after Columbus, maize provoked a silence revolution on north and central region of Portugal, reshaping crop systems, agronomy, landscape and culture along the years. In the 1940s’ the advent of American hybrid seeds success started to contribute to genetic erosion. At NUMI (Maize Breeding Station at Braga) Silas Pêgo understood this threat and several maize collecting missions were organized. This collecting missions, paved the way for ex-situ conservation. In addition they feed in-situ/on farm and on station activities via prebreeding.(...)
- Inhibition of SNF1-related protein kinase1 by trehalose 6-phosphate and other metabolites and the interrelation with plant gorwthPublication . Nunes, Cátia Maria de Jesus; Fevereiro, PedroAll life forms need to monitor carbon and energy availability to survive and this is especially true for plants which must integrate unavoidable environmental conditions with metabolism for cellular homeostasis maintenance. Sugars, in the heart of metabolism, are now recognized as crucial signaling molecules that translate those conditions. One such signal is trehalose 6- phosphate (T6P), a phosphorylated dimer of glucose molecules which levels correlate well with those of sucrose (Suc). Central integrators of stress and energy regulation include the conserved plant Snf1-related kinase1 (SnRK1) which respond to low cellular energy levels by up-regulating energy conserving and catabolic metabolism and down-regulating energy consuming processes. In 2009 T6P was shown to inhibit SnRK1. The in vitro inhibition of SnRK1 by T6P was confirmed in vivo through the observation that genes normally induced by SnRK1 were repressed by T6P and vice-versa, promoting growth processes. These observations provided a model for the regulation of growth by sugar.(...)
- MicroRNAs as modulators of water deficit responses in Medicago truncatulaPublication . Trindade, Inês Garcia de Oliveira; Fevereiro, Manuel PedroGeneral abstract The decrease in water availability is one of the main factors responsible for crop losses worldwide. In order to improve their tolerance to water deprivation, plants have developed a variety of morphological, biochemical and molecular adaptations that involve the modulation of gene expression. Over the last decade, small RNAs, namely microRNAs (miRNAs), have been shown to participate in these mechanisms in several plant species. However, little is known about their role in legumes, a plant family of high economical and ecological value.(...)
- Transformation of Medicago truncatula with the arginine decarboxylase gene to modify polyamine metabolism toward water deficit resistancePublication . Duque, Ana Sofia Roldão; Fevereiro, Pedro Salema; Santos, DulceThe main purpose of this thesis was to introduce and express in the model legume Medicago truncatula the arginine decarboxylase encoding gene (Adc) from Avena sativa, that codes for a key enzyme of the polyamine biosynthetic pathway, to modify polyamine metabolism aiming to alter the plant responses to water deficit. Water deficit is the major abiotic stress that severely limits crop yields and controls the distribution of vegetation over the earth's surface. Due to their capacity to grow on nitrogen-poor soils, legumes are important candidates for improving saline soil fertility and helping to reintroduce agriculture to dehydrated lands. Efforts in developing legume crops with better drought/water deficit resistance through conventional breeding have been restricted, mainly because of underprovided understanding of the physiological mechanisms underlying stress resistance and to the lack of sufficient polymorphism for drought resistancerelated traits. The alternative process of generating transgenic cultivars requires success in the transformation method and proper incorporation of stress resistance into plants. Further evaluation of the transgenic plants under stress conditions and understanding the physiological effect of the inserted genes at the whole plant level are also essential for the success of this technology. Towards the usefulness of developing a model system, Medicago truncatula has become increasingly relevant in latest years due to significant progress at the genetic and genomic levels in this specie.(...)