title: Brevis plant1, a putative inositol polyphosphate 5-phosphatase, is required for internode elongation in maize.
abstract: In maize (Zea mays L.), as in other grass species, stem elongation occurs during growth and most noticeably upon the transition to flowering. Genes that reduce stem elongation have been important to reduce stem breakage, or lodging. Stem elongation has been mediated by dwarf and brachytic/brevis plant mutants that affect giberellic acid and auxin pathways, respectively. Maize brevis plant1 (bv1) mutants, first identified over 80 years ago, strongly resemble brachytic2 mutants that have shortened internodes, short internode cells, and are deficient in auxin transport. Here, we characterized two novel bv1 maize mutants. We found that an inositol polyphosphate 5-phosphatase orthologue of the rice gene dwarf50 was the molecular basis for the bv1 phenotype, implicating auxin-mediated inositol polyphosphate and/or phosphoinositide signalling in stem elongation. We suggest that auxin-mediated internode elongation involves processes that also contribute to stem gravitropism. Genes misregulated in bv1 mutants included genes important for cell wall synthesis, transmembrane transport, and cytoskeletal function. Mutant and wild-type plants were indistinguishable early in development, responded similarly to changes in light quality, had unaltered flowering times, and had normal flower development. These attributes suggest that breeding could utilize bv1 alleles to increase crop grain yields.
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Avila
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Diego
authors.initials: D
authors.lastname: Cerrudo
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada.
authors.forename: Clarence
authors.initials: C
authors.lastname: Swanton
authors.affiliation: Department of Plant Agriculture, University of Guelph, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada llukens@uoguelph.ca.
authors.forename: Lewis
authors.initials: L
authors.lastname: Lukens
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056426:Genetic Loci; D000072181:Inositol Polyphosphate 5-Phosphatases / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018547:Plant Stems / Q000254:growth & development*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D003313:Zea mays / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics*
chemical_list: D010940:Plant Proteins; D000072181:Inositol Polyphosphate 5-Phosphatases
keywords: Brachytic; br3; brevis plant1; bv1; cell elongation; development; growth; internode elongation; plant height.