8 research outputs found

    The rice mitochondrial iron transporter is essential for plant growth

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    In plants, iron (Fe) is essential for mitochondrial electron transport, heme, and Fe-Sulphur (Fe-S) cluster synthesis; however, plant mitochondrial Fe transporters have not been identified. Here we show, identify and characterize the rice mitochondrial Fe transporter (MIT). Based on a transfer DNA library screen, we identified a rice line showing symptoms of Fe deficiency while accumulating high shoot levels of Fe. Homozygous knockout of MIT in this line resulted in a lethal phenotype. MIT localized to the mitochondria and complemented the growth of Δmrs3Δmrs4 yeast defective in mitochondrial Fe transport. The growth of MIT-knockdown (mit-2) plants was also significantly impaired despite abundant Fe accumulation. Further, the decrease in the activity of the mitochondrial and cytosolic Fe-S enzyme, aconitase, indicated that Fe-S cluster synthesis is affected in mit-2 plants. These results indicate that MIT is a mitochondrial Fe transporter essential for rice growth and development

    The proton pump interactor (Ppi) gene family of Arabidopsis thaliana : expression pattern of Ppi1 and characterisation of knockout mutants for Ppi1 and 2

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    Plant plasma membrane H+-ATPases (PM H+-ATPase) are essential for establishing a proton electrochemical gradient across the cell plasma membrane. Their regulation is poorly understood, except for the role of 14-3-3 proteins, which relieve autoinhibition from the C-terminal domain. A novel protein interacting with this domain was recently identified in Arabidopsis and named PPI1 (Proton Pump Interactor 1). PPI1 stimulates PM H+-ATPase activity in vitro. Here, we analyse the expression pattern of Ppi1 using beta-glucuronidase as a reporter. Expression is strong in root and shoot vascular systems, particularly in meristematic and sink tissues, as well as in pollen, stigmas and siliques, but not in developing embryos. Removal of the first intron decreased GUS expression 45-fold. We also analysed the transcription of Ppi2, another gene in the family, and demonstrated that Ppi2 is expressed in seedlings, cultured cells and flowers. We reassessed Ppi2 gene structure based on RT-PCR amplifications, cDNA data and similarity to other Ppi genes. Insertional mutants for both Ppi1 and Ppi2 were isolated. Two different mutants of Ppi1 showed aberrant mRNAs and lacked any detectable protein and are therefore true knockouts. Interestingly, one mutation inhibited the splicing of one intron at a considerable distance (>700 bp) from the T-DNA insertion site, but not the splicing of a proximal intron (29 bp) or of any other intron. At the plant level, neither of the single mutants nor the double ppi1ppi2 mutant showed an altered phenotype in standard growth conditions under acid load or salt stres

    ORTHOIMAGES AS A TOOL FOR LAND PLANNING: ΑΝ ΑΡΡLΙCΑΤΙΟΝ ΤΟ ΤΗΕ RΕGΙΟΝΕ ΡΙΕΜΟΝΤΕ’S «WATER CONSERVATION PLAN»

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    Nell'ambito delle indagini del Piano di Tutela delle Acque è stato elaborato e verificato tramite rilevamenti GPS, un ortomosaico a supporto delle analisi ecosistemiche. Tramite fotointerpretazione di una fascia prospiciente l'alveo sono stati estratti degli indici di naturalità e qualità ambientale. L'aggregazione di tali indici ha quindi permesso di rappresentare lo stato della risorsa acqua secondo una classificazione basata sul degrado a supporto delle future operazioni di pianificazione territoriale.During the studies of the Water Conservation Plan we have rectified and verified with a GPS Surveya mosaic of aerial photogramsas a tool for environmental analisyS. Using photointepretation on a buffer of the riverbed we extracted naturality and environmental quality indexes. The aggregation of these indexes represents the actual health level of the water body with a decay based classification, this will be a useful tool for land planning

    Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 10

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    In this contribution, new data concerning red algae, bryophytes, fungi and lichens of the Italian flora are presented. It includes new records and confirmations for the algal genus Thorea, for the bryophyte genera Ephemerum, Hedwigia, Pogonatum, Riccia, Sphagnum, and Tortella, the fungal genera Pileolaria and Sporisorium, and the lichen genera Bacidia, Cerothallia, Chaenotheca, Cladonia, Halecania, Lecanora, Phylloblastia, Physcia, Protoparmelia, Pycnora, Segestria, and Sphaerophorus

    Notulae to the Italian flora of algae, bryophytes, fungi and lichens: 10

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    In this contribution, new data concerning red algae, bryophytes, fungi and lichens of the Italian flora are presented. It includes new records and confirmations for the algal genus Thorea, for the bryophyte genera Ephemerum, Hedwigia, Pogonatum, Riccia, Sphagnum, and Tortella, the fungal genera Pileolaria and Sporisorium, and the lichen genera Bacidia, Cerothallia, Chaenotheca, Cladonia, Halecania, Lecanora, Phylloblastia, Physcia, Protoparmelia, Pycnora, Segestria, and Sphaerophoru

    Frataxin Is Localized to Both the Chloroplast and Mitochondrion and Is Involved in Chloroplast Fe-S Protein Function in Arabidopsis.

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    Frataxin plays a key role in eukaryotic cellular iron metabolism, particularly in mitochondrial heme and iron-sulfur (Fe-S) cluster biosynthesis. However, its precise role has yet to be elucidated. In this work, we studied the subcellular localization of Arabidopsis frataxin, AtFH, using confocal microscopy, and found a novel dual localization for this protein. We demonstrate that plant frataxin is targeted to both the mitochondria and the chloroplast, where it may play a role in Fe-S cluster metabolism as suggested by functional studies on nitrite reductase (NIR) and ferredoxin (Fd), two Fe-S containing chloroplast proteins, in AtFH deficient plants. Our results indicate that frataxin deficiency alters the normal functioning of chloroplasts by affecting the levels of Fe, chlorophyll, and the photosynthetic electron transport chain in this organelle

    Iron Uptake and Transport in Plants: The Good, the Bad, and the Ionome

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