title: The developmental and environmental regulation of gravitropic setpoint angle in Arabidopsis and bean.
abstract: Root and shoot branches are major determinants of plant form and critical for the effective capture of resources below and above ground. These branches are often maintained at specific angles with respect to gravity, known as gravitropic set point angles (GSAs). We have previously shown that the mechanism permitting the maintenance of non-vertical GSAs is highly auxin-dependent and here we investigate the developmental and environmental regulation of root and shoot branch GSA. We show that nitrogen and phosphorous deficiency have opposing, auxin signalling-dependent effects on lateral root GSA in Arabidopsis: while low nitrate induces less vertical lateral root GSA, phosphate deficiency results in a more vertical lateral root growth angle, a finding that contrasts with the previously reported growth angle response of bean adventitious roots. We find that this root-class-specific discrepancy in GSA response to low phosphorus is mirrored by similar differences in growth angle response to auxin treatment between these root types. Finally we show that both shaded, low red/far-red light conditions and high temperature induce more vertical growth in Arabidopsis shoot branches. We discuss the significance of these findings in the context of efforts to improve crop performance via the manipulation of root and shoot branch growth angle.
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds, UK.
authors.forename: Suruchi
authors.initials: S
authors.lastname: Roychoudhry
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds, UK.
authors.forename: Martin
authors.initials: M
authors.lastname: Kieffer
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds, UK.
authors.forename: Marta
authors.initials: M
authors.lastname: Del Bianco
authors.affiliation: Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.
authors.forename: Che-Yang
authors.initials: CY
authors.lastname: Liao
authors.affiliation: Laboratory of Biochemistry, Wageningen University, Wageningen, The Netherlands.
authors.forename: Dolf
authors.initials: D
authors.lastname: Weijers
authors.affiliation: Centre for Plant Sciences, University of Leeds, Leeds, UK.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kepinski
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D004777:Environment; D018522:Gravitropism; D007210:Indoleacetic Acids / Q000378:metabolism / Q000494:pharmacology; D008027:Light; D009566:Nitrates / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D063245:Plant Development; D018517:Plant Roots / Q000502:physiology; D013696:Temperature
chemical_list: D007210:Indoleacetic Acids; D009566:Nitrates; D010710:Phosphates