Utilization and transport of mannitol in Olea europaea and their implications on salt stress tolerance

Comunicação em painel no congresso "14th Congress of the Federation of European Societies of Plant Biology". August 23-27. 2004. Cracow. Poland.Fundação para a Ciência e a Tecnologia (FCT

Responses to hydric stress in the seed-borne necrotrophic fungus Alternaria brassicicola

Alternaria brassicicola is a necrotrophic fungus causing black spot disease and is an economically important seed-borne pathogen of cultivated brassicas. Seed transmission is a crucial component of its parasitic cycle as it promotes long-term survival and dispersal. Recent studies, conducted with the Arabidopsis thaliana/A. brassicicola pathosystem, showed that the level of susceptibility of the fungus to water stress strongly influenced its seed transmission ability. In this study, we gained further insights into the mechanisms involved in the seed infection process by analyzing the transcriptomic and metabolomic responses of germinated spores of A. brassicicola exposed to water stress. Then, the repertoire of putative hydrophilins, a group of proteins that are assumed to be involved in cellular dehydration tolerance, was established in A. brassicicola based on the expression data and additional structural and biochemical criteria. Phenotyping of single deletion mutants deficient for fungal hydrophilin-like proteins showed that they were affected in their transmission to A. thaliana seeds, although their aggressiveness on host vegetative tissues remained intact

Modalites et causes possibles du developpement d'une sensibilite au pH de l'absorption du saccharose par les tissus foliaires au cours de la survie

SIGLECNRS T 56622 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Etude du transport du saccharose dans les tissus foliaires : approche physiologique, biochimique et immunologique

CNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Sugar transporters in higher plants – a diversity of roles and complex regulation

Sugar-transport proteins play a crucial role in the cell-to-cell and long-distance distribution of sugars throughout the plant. In the past decade, genes encoding sugar transporters (or carriers) have been identified, functionally expressed in heterologous systems, and studied with respect to their spatial and temporal expression. Higher plants possess two distinct families of sugar carriers: the disaccharide transporters that primarily catalyse sucrose transport and the monosaccharide transporters that mediate the transport of a variable range of monosaccharides. The tissue and cellular expression pattern of the respective genes indicates their specific and sometimes unique physiological tasks. Some play a purely nutritional role and supply sugars to cells for growth and development, whereas others are involved in generating osmotic gradients required to drive mass flow or movement. Intriguingly, some carriers might be involved in signalling. Various levels of control regulate these sugar transporters during plant development and when the normal environment is perturbed. This article focuses on members of the monosaccharide transporter and disaccharide transporter families, providing details about their structure, function and regulation. The tissue and cellular distribution of these sugar transporters suggests that they have interesting physiological roles

Salt Effect on Biochemical Behavior Fodder Halophytes

International audienc

Sugar and polyol carriers expression during fruit ripening in Olea europaea

Poster apresentado no "IX Congresso Luso-Espanhol de Fisiologia Vegetal" realizado em Évora, Portugal, em Setembro de 2005.Resource allocation is an important and highly integrated process in higher plants involving the transport of photoassimilates from source to sink organs. Mannitol and sucrose are the primary photosynthetic products and the major phloem-translocated carbohydrates in Olea europaea L., an important and widespread crop in the Mediterranean basin. In suspension cultured cells of O. europaea, we have previously identified and characterized a H+-dependent polyol transport system whose activity was correlated with OeMaT1 (Olea europaea Mannitol Transporter) expression. Mannitol transport activity and OeMaT1 transcription increased under salt stress conditions, suggesting that the polyol behaves as an important osmolyte in O. europaea. In this work, RT-PCR performed on RNA extracted from olive fruit allowed the cloning of the monosaccharide transporter OeMST2 and the sucrose transporter OeSUT1. To understand key steps in long distance transport, and particularly partitioning and accumulation of polyol and sugars in olive fruit, the expression of OeMaT1, OeMST2 and OeSUT1, as well as sugar and polyol content were studied during the ripening process. Expression analysis showed an increased level of transcripts in the latter stages, suggesting that polyol and sugar carriers have a major role in the massive accumulation of photoassimilates that occurs during olive fruit maturation.Fundação para a Ciência e a Tecnologia (FCT)