title: Early development and gravitropic response of lateral roots in Arabidopsis thaliana.
abstract: Root system architecture plays an important role in determining nutrient and water acquisition and is modulated by endogenous and environmental factors, resulting in considerable developmental plasticity. The orientation of primary root growth in response to gravity (gravitropism) has been studied extensively, but little is known about the behaviour of lateral roots in response to this signal. Here, we analysed the response of lateral roots to gravity and, consistently with previous observations, we showed that gravitropism was acquired slowly after emergence. Using a lateral root induction system, we studied the kinetics for the appearance of statoliths, phloem connections and auxin transporter gene expression patterns. We found that statoliths could not be detected until 1 day after emergence, whereas the gravitropic curvature of the lateral root started earlier. Auxin transporters modulate auxin distribution in primary root gravitropism. We found differences regarding PIN3 and AUX1 expression patterns between the lateral root and the primary root apices. Especially PIN3, which is involved in primary root gravitropism, was not expressed in the lateral root columella. Our work revealed new developmental transitions occurring in lateral roots after emergence, and auxin transporter expression patterns that might explain the specific response of lateral roots to gravity.
authors.affiliation: Université Montpellier 2, UMR DIADE, Equipe Rhizogenèse, 911 Avenue Agropolis, 34394 Montpellier cedex 5, France.
authors.forename: S
authors.initials: S
authors.lastname: Guyomarc'h
authors.forename: S
authors.initials: S
authors.lastname: Léran
authors.forename: M
authors.initials: M
authors.lastname: Auzon-Cape
authors.forename: F
authors.initials: F
authors.lastname: Perrine-Walker
authors.forename: M
authors.initials: M
authors.lastname: Lucas
authors.forename: L
authors.initials: L
authors.lastname: Laplaze
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018522:Gravitropism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D018519:Meristem / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D052585:Phloem / Q000254:growth & development / Q000378:metabolism; D059828:Plant Cells / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D021381:Protein Transport
chemical_list: C100794:AUX1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; C449300:PIN3 protein, Arabidopsis; D010940:Plant Proteins; C078729:sucrose transport protein, plant; D049452:Green Fluorescent Proteins