title: A tomato phloem-mobile protein regulates the shoot-to-root ratio by mediating the auxin response in distant organs.
abstract: The plant vascular system serves as a conduit for delivery of both nutrients and signaling molecules to various distantly located organs. The anucleate sieve tube system of the angiosperm phloem delivers sugars and amino acids to developing organs, and has recently been shown to contain a unique population of RNA and proteins. Grafting studies have established that a number of these macromolecules are capable of moving long distances between tissues, thus providing support for operation of a phloem-mediated inter-organ communication network. Currently, our knowledge of the roles played by such phloem-borne macromolecules is in its infancy. Here, we show that, in tomato, translocation of a phloem-mobile cyclophilin, SlCyp1, from a wild-type scion into a mutant rootstock results in restoration of vascular development and lateral root initiation. This process occurs through reactivation of auxin response pathways and reprogramming of the root transcriptome. Moreover, we show that long-distance trafficking of SlCyp1 is associated with regulation of the shoot-to-root ratio in response to changing light intensities, by modulating root growth. We conclude that long-distance trafficking of SlCyp1 acts as a rheostat to control the shoot-to-root ratio, by mediating root development to integrate photosynthesis and light intensity with requirements for access to water and mineral nutrients.
authors.affiliation: The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, and The Otto Warburg Minerva Centre for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Spiegelman
authors.affiliation: Department of Plant Biology, College of Biological Sciences, University of California at Davis, Davis, CA, 95616, USA.
authors.forename: Byung-Kook
authors.initials: BK
authors.lastname: Ham
authors.affiliation: Department of Plant Biology, College of Biological Sciences, University of California at Davis, Davis, CA, 95616, USA.
authors.forename: Zhaoliang
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Plant Biology, College of Biological Sciences, University of California at Davis, Davis, CA, 95616, USA.
authors.forename: Ted W
authors.initials: TW
authors.lastname: Toal
authors.affiliation: Department of Plant Biology, College of Biological Sciences, University of California at Davis, Davis, CA, 95616, USA.
authors.forename: Siobhan M
authors.initials: SM
authors.lastname: Brady
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, NY, 14853, USA.|US Department of Agriculture, Robert W. Holley Center for Agriculture and Health, Ithaca, NY, 14853, USA.
authors.forename: Zhangjun
authors.initials: Z
authors.lastname: Fei
authors.affiliation: Department of Plant Biology, College of Biological Sciences, University of California at Davis, Davis, CA, 95616, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Lucas
authors.affiliation: The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, and The Otto Warburg Minerva Centre for Agricultural Biotechnology, The Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, 76100, Israel.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Wolf
mesh_terms: D001692:Biological Transport; D021983:Cyclophilins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D018551:Solanum lycopersicum / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D052585:Phloem / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis / Q000502:physiology; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018520:Plant Shoots / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D030821:Plants, Genetically Modified; D015398:Signal Transduction
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins; D021983:Cyclophilins
keywords: Solanum lycopersicum; auxin; cyclophilin; diageotropica; phloem; root development; shoot-to-root ratio