Blue‐light‐induced PIN3 polarization for root negative phototropic response in Arabidopsis

• Published in: The Plant journal : for cell and molecular biology Vol. 76; no. 2; pp. 308 - 321
• Main Authors: Zhang, Kun‐Xiao, Xu, Heng‐Hao, Yuan, Ting‐Ting, Zhang, Liang, Lu, Ying‐Tang
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.10.2013
• Subjects: Arabidopsis - genetics; Arabidopsis - physiology; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - physiology; asymmetric auxin distribution; blue light; GNOM; Indoleacetic Acids - metabolism; Light; Molecular biology; Phototropism - physiology; PID/PP2A; PIN3 polarization; Plant biology; Plant growth; Plant Roots - physiology; Plant Roots - radiation effects; Plants, Genetically Modified - genetics; Plants, Genetically Modified - physiology; Protein Phosphatase 2 - physiology; Protein Transport; Protein-Serine-Threonine Kinases - physiology; PID/PP2A; blue light; asymmetric auxin distribution; GNOM; PIN3 polarization
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1111/tpj.12298

Summary 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.