Iskanje po repozitoriju

A+ | A- | | SLO | ENG

Opis: The yields of worldwide crop production are negatively affected by adverse environmental conditions, such as drought, salinity, heavy metal contamination and nutrient depletion in cultivated soils (Yan et al., 2013; Golldack et al., 2011; Yadav, 2010; Kobayashi and Nishizawa, 2012). This reduced crop production constitutes a major problem for food sustainability world-wide (Spiertz, 2013). Indeed, one of the major challenges for plant biotechnology will be to satisfy the increased demand for food on one hand, and to compensate for the loss of crop production on the other. Thus, the discovery of new plant genes that are able to cope with these conditions is critical and expected not only to elucidate the molecular mechanisms underlying crop abiotic stress, but also to pioneer genetic engineering strategies for improved crop productivity. The goal of this project was to identify novel genes belonging to the Major Facilitator Superfamily (MFS) of plant membrane transporters with potential major roles in conferring abiotic stress tolerance, namely to heavy metal, osmotic and iron deficiency stress. We selected three Arabidopsis thaliana MFS transporter genes, provisionally called MFS10, MFS11 and MFS12, which based on publicly available microarray data display specific expression patterns suggesting roles in plant tolerance to different abiotic stresses. RT-PCR analyses showed that in fact the MFS10 gene is highly induced by cadmium (Cd), selenium (Se), salt and mannitol, while the MFS11 gene is upregulated by abscisic acid (ABA) and glucose, and the MFS12 gene by iron (Fe) deficiency, ABA and glucose. Furthermore, subcellular localization of fluorescent reporter fusions indicated that the MFS10 and MFS11 gene products are both plasma membrane localized transporters, while the encoded product of the MFS12 gene appears to be an endoplasmic reticulum localized transporter. Finally, reverse genetics using a null mutant allele for the MFS10 gene demonstrated that it functions as a regulator of plant responses to hyperosmotic (drought and salt) stress.
Ključne besede: Major Facilitator Superfamily (MFS), abiotic stress tolerance, heavy metals, osmotic stress, ABA stress, iron deficiency, T-DNA insertion lines, RT-PCR, confocal microscopy.
Objavljeno v RUNG: 03.05.2022; Ogledov: 1351; Prenosov: 0
Gradivo ima več datotek! Več...

Opis: Uranium contamination of surface environments is a problem associated with both U-ore extraction/processing and situations in which groundwater comes into contact with geological formations high in uranium. Apart from the environmental concerns about U contamination, its accumulation and isotope composition have been used in marine sediments as a paleoproxy of the Earth’s oxygenation history. Understanding U isotope geochemistry is then essential either to develop sustainable remediation procedures as well as for use in paleotracer applications. We report on parameters controlling U immobilization and U isotope fractionation by adsorption onto Mn/Fe oxides, precipitation with phosphate, and biotic reduction. The light U isotope (235U) is preferentially adsorbed on Mn/Fe oxides in an oxic system. When adsorbed onto Mn/Fe oxides, dissolved organic carbon and carbonate are the most efficient ligands limiting U binding resulting in slight differences in U isotope composition (δ238U = 0.22 ± 0.06‰) compared to the DOC/DIC-free configuration (δ238U = 0.39 ± 0.04‰). Uranium precipitation with phosphate does not induce isotope fractionation. In contrast, during U biotic reduction, the heavy U isotope (238U) is accumulated in reduced species (δ238U up to −1‰). The different trends of U isotope fractionation in oxic and anoxic environments makes its isotope composition a useful tracer for both environmental and paleogeochemical applications.
Ključne besede: Uranium, fractionation, biotic, abiotic, oxides
Objavljeno v RUNG: 04.10.2019; Ogledov: 2904; Prenosov: 0
Gradivo ima več datotek! Več...