title: The boron efflux transporter ROTTEN EAR is required for maize inflorescence development and fertility.
abstract: Although boron has a relatively low natural abundance, it is an essential plant micronutrient. Boron deficiencies cause major crop losses in several areas of the world, affecting reproduction and yield in diverse plant species. Despite the importance of boron in crop productivity, surprisingly little is known about its effects on developing reproductive organs. We isolated a maize (Zea mays) mutant, called rotten ear (rte), that shows distinct defects in vegetative and reproductive development, eventually causing widespread sterility in its inflorescences, the tassel and the ear. Positional cloning revealed that rte encodes a membrane-localized boron efflux transporter, co-orthologous to the Arabidopsis thaliana BOR1 protein. Depending on the availability of boron in the soil, rte plants show a wide range of phenotypic defects that can be fully rescued by supplementing the soil with exogenous boric acid, indicating that rte is crucial for boron transport into aerial tissues. rte is expressed in cells surrounding the xylem in both vegetative and reproductive tissues and is required for meristem activity and organ development. We show that low boron supply to the inflorescences results in widespread defects in cell and cell wall integrity, highlighting the structural importance of boron in the formation of fully fertile reproductive organs.
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, New Jersey 08854-8020.
authors.forename: Mithu
authors.initials: M
authors.lastname: Chatterjee
authors.affiliation: Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093-0116.
authors.forename: Zara
authors.initials: Z
authors.lastname: Tabi
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, New Jersey 08854-8020.
authors.forename: Mary
authors.initials: M
authors.lastname: Galli
authors.affiliation: Department of Biological Sciences, California State University Long Beach, Long Beach, California 90840 Division of Environmental Biology, National Science Foundation, Arlington, Virginia 22230.
authors.forename: Simon
authors.initials: S
authors.lastname: Malcomber
authors.affiliation: Section of Cell and Developmental Biology, University of California San Diego, La Jolla, California 92093-0116.
authors.forename: Amy
authors.initials: A
authors.lastname: Buck
authors.affiliation: Department of Genetics, Development, and Cell Biology, Iowa State University, Iowa 50011-2156.
authors.forename: Michael
authors.initials: M
authors.lastname: Muszynski
authors.affiliation: Waksman Institute, Rutgers University, Piscataway, New Jersey 08854-8020 Department of Plant Biology and Pathology, Rutgers University, New Brunswick, New Jersey 08901 agallavotti@waksman.rutgers.edu.
authors.forename: Andrea
authors.initials: A
authors.lastname: Gallavotti
mesh_terms: D017920:Antiporters / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics; D001692:Biological Transport; D001895:Boron / Q000378:metabolism*; D002473:Cell Wall / Q000187:drug effects; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D005298:Fertility; D018506:Gene Expression Regulation, Plant; D056626:Inflorescence / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018519:Meristem / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D012098:Reproduction; D052584:Xylem / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000648:ultrastructure
chemical_list: D017920:Antiporters; D029681:Arabidopsis Proteins; C469216:BOR1 protein, Arabidopsis; D026901:Membrane Transport Proteins; D010940:Plant Proteins; D001895:Boron