title: Arabidopsis type I proton-pumping pyrophosphatase expresses strongly in phloem, where it is required for pyrophosphate metabolism and photosynthate partitioning.
abstract: Phloem loading is a critical process in plant physiology. The potential of regulating the translocation of photoassimilates from source to sink tissues represents an opportunity to increase crop yield. Pyrophosphate homeostasis is crucial for normal phloem function in apoplasmic loaders. The involvement of Arabidopsis (Arabidopsis thaliana) type I proton-pumping pyrophosphatase (AVP1) in phloem loading was analyzed at genetic, histochemical, and physiological levels. A transcriptional AVP1 promoter::GUS fusion revealed phloem activity in source leaves. Ubiquitous AVP1 overexpression (35S::AVP1 cassette) enhanced shoot biomass, photoassimilate production and transport, rhizosphere acidification, and expression of sugar-induced root ion transporter genes (POTASSIUM TRANSPORTER2 [KUP2], NITRATE TRANSPORTER2.1 [NRT2.1], NRT2.4, and PHOSPHATE TRANSPORTER1.4 [PHT1.4]). Phloem-specific AVP1 overexpression (Commelina Yellow Mottle Virus promoter [pCOYMV]::AVP1) elicited similar phenotypes. By contrast, phloem-specific AVP1 knockdown (pCoYMV::RNAiAVP1) resulted in stunted seedlings in sucrose-deprived medium. We also present a promoter mutant avp1-2 (SALK046492) with a 70% reduction of expression that did not show severe growth impairment. Interestingly, AVP1 protein in this mutant is prominent in the phloem. Moreover, expression of an Escherichia coli-soluble pyrophosphatase in the phloem (pCoYMV::pyrophosphatase) of avp1-2 plants resulted in severe dwarf phenotype and abnormal leaf morphology. We conclude that the Proton-Pumping Pyrophosphatase AVP1 localized at the plasma membrane of the sieve element-companion cell complexes functions as a synthase, and that this activity is critical for the maintenance of pyrophosphate homeostasis required for phloem function.
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Gaston A
authors: GA
authors: Pizzio
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Julio
authors: J
authors: Paez-Valencia
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Aswad S
authors: AS
authors: Khadilkar
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Kamesh
authors: K
authors: Regmi
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Araceli
authors: A
authors: Patron-Soberano
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Shangji
authors: S
authors: Zhang
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Jonathan
authors: J
authors: Sanchez-Lares
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Tara
authors: T
authors: Furstenau
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Jisheng
authors: J
authors: Li
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Concepcion
authors: C
authors: Sanchez-Gomez
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Pedro
authors: P
authors: Valencia-Mayoral
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Umesh P
authors: UP
authors: Yadav
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.).
authors: Brian G
authors: BG
authors: Ayre
authors: School of Life Sciences, Arizona State University, Tempe, Arizona 852872 (G.A.P., J.P.-V., K.R., S.Z., J.S.-L., T.F., J.L., R.A.G.);Department of Botany, University of Wisconsin, Madison, Wisconsin 53706 (J.P.-V.);Department of Biological Sciences, University of North Texas, Denton, Texas 762031 (A.S.K., U.P.Y., B.G.A.);División de Biología Molecular, Laboratorio Nacional de Investigaciones en Nanociencias y Nanotecnología Instituto Potosino de Investigación Científica y Tecnológica, A.C. 78216 San Luis Potosí, Mexico (A.P.-S.); andDepartamento de Patología, Hospital Infantil de México, Federico Gómez, Mexico (C.S.-G., P.V.-M.) roberto.gaxiola@asu.edu.
authors: Roberto A
authors: RA
authors: Gaxiola
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D011756:Diphosphates / Q000378:metabolism*; D015870:Gene Expression; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D006706:Homeostasis; D043564:Inorganic Pyrophosphatase / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D009928:Organ Specificity; D010641:Phenotype; D052585:Phloem / Q000201:enzymology / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D018520:Plant Shoots / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development; D013395:Sucrose / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D011756:Diphosphates; C107241:diphosphoric acid; D013395:Sucrose; C505048:AVP1 protein, Arabidopsis; D043564:Inorganic Pyrophosphatase