title: Expression of peach sucrose transporters in heterologous systems points out their different physiological role.
abstract: Sucrose is the major phloem-translocated component in a number of economically important plant species. The comprehension of the mechanisms involved in sucrose transport in peach fruit appears particularly relevant, since the accumulation of this sugar, during ripening, is crucial for the growth and quality of the fruit. Here, we report the functional characterisation and subcellular localisation of three sucrose transporters (PpSUT1, PpSUT2, PpSUT4) in peach, and we formulate novel hypotheses about their role in accumulation of sugar. We provide evidence, about the capability of both PpSUT1 and PpSUT4, expressed in mutant yeast strains to transport sucrose. The functionality of PpSUT1 at the plasma membrane, and of PpSUT4 at the tonoplast, has been demonstrated. On the other hand, the functionality of PpSUT2 was not confirmed: this protein is unable to complement two sucrose uptake-deficient mutant yeast strains. Our results corroborate the hypotheses that PpSUT1 partakes in phloem loading in leaves, and PpSUT4 sustains cell metabolism by regulating sucrose efflux from the vacuole.
authors.affiliation: Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy. Electronic address: laura.zanon@uniud.it.
authors.forename: Laura
authors.initials: L
authors.lastname: Zanon
authors.affiliation: Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy. Electronic address: rachele.falchi@uniud.it.
authors.forename: Rachele
authors.initials: R
authors.lastname: Falchi
authors.affiliation: Department of Plant Physiology, Humboldt University of Berlin, Philippstr. 13, Building 12, 10115 Berlin, Germany. Electronic address: hackelal@rz.hu-berlin.de.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Hackel
authors.affiliation: Department of Plant Physiology, Humboldt University of Berlin, Philippstr. 13, Building 12, 10115 Berlin, Germany. Electronic address: christina.kuehn@biologie.hu-berlin.de.
authors.forename: Christina
authors.initials: C
authors.lastname: Kühn
authors.affiliation: Dipartimento di Scienze Agrarie e Ambientali, University of Udine, via delle Scienze 206, 33100 Udine, Italy. Electronic address: giannina.vizzotto@uniud.it.
authors.forename: Giannina
authors.initials: G
authors.lastname: Vizzotto
mesh_terms: D004929:Esculin / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D025941:Protein Interaction Mapping; D000068239:Prunus persica / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D014026:Nicotiana / Q000166:cytology; D025801:Ubiquitin / Q000378:metabolism
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; D025801:Ubiquitin; C078729:sucrose transport protein, plant; D004929:Esculin
keywords: Assimilates partitioning; Fluorescent tag fusion proteins; Phloem; Prunus persica; Split ubiquitin assay; Yeast complementation assay