title: Blue-light-induced PIN3 polarization for root negative phototropic response in Arabidopsis.
abstract: Root negative phototropism is an important response in plants. Although blue light is known to mediate this response, the cellular and molecular mechanisms underlying root negative phototropism remain unclear. Here, we report that the auxin efflux carrier PIN-FORMED (PIN) 3 is involved in asymmetric auxin distribution and root negative phototropism. Unilateral blue-light illumination polarized PIN3 to the outer lateral membrane of columella cells at the illuminated root side, and increased auxin activity at the illuminated side of roots, where auxin promotes growth and causes roots bending away from the light source. Furthermore, root negative phototropic response and blue-light-induced PIN3 polarization were modulated by a brefeldin A-sensitive, GNOM-dependent, trafficking pathway and by phot1-regulated PINOID (PID)/PROTEIN PHOSPHATASE 2A (PP2A) activity. Our results indicate that blue-light-induced PIN3 polarization is needed for asymmetric auxin distribution during root negative phototropic response.
authors.affiliation: Key Lab of MOE for Plant Development, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
authors.forename: Kun-Xiao
authors.initials: KX
authors.lastname: Zhang
authors.forename: Heng-Hao
authors.initials: HH
authors.lastname: Xu
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Yuan
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.forename: Ying-Tang
authors.initials: YT
authors.lastname: Lu
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D007210:Indoleacetic Acids / Q000378:metabolism; D008027:Light; D018524:Phototropism / Q000502:physiology*; D018517:Plant Roots / Q000502:physiology* / Q000528:radiation effects; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D054648:Protein Phosphatase 2 / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D021381:Protein Transport
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; C449300:PIN3 protein, Arabidopsis; C405165:PINOID protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; C580624:PP2A-2 protein, Arabidopsis; D054648:Protein Phosphatase 2
keywords: GNOM; PID/PP2A; PIN3 polarization; asymmetric auxin distribution; blue light