title: Phototropism: at the crossroads of light-signaling pathways.
abstract: Phototropism enables plants to orient growth towards the direction of light and thereby maximizes photosynthesis in low-light environments. In angiosperms, blue-light photoreceptors called phototropins are primarily involved in sensing the direction of light. Phytochromes and cryptochromes (sensing red/far-red and blue light, respectively) also modulate asymmetric hypocotyl growth, leading to phototropism. Interactions between different light-signaling pathways regulating phototropism occur in cryptogams and angiosperms. In this review, we focus on the molecular mechanisms underlying the co-action between photosensory systems in the regulation of hypocotyl phototropism in Arabidopsis thaliana. Recent studies have shown that phytochromes and cryptochromes enhance phototropism by controlling the expression of important regulators of phototropin signaling. In addition, phytochromes may also regulate growth towards light via direct interaction with the phototropins.
authors.affiliation: Centre for Integrative Genomics, University of Lausanne, Genopode Building, CH 1015 Lausanne, Switzerland.
authors.forename: Anupama
authors.initials: A
authors.lastname: Goyal
authors.forename: Bogna
authors.initials: B
authors.lastname: Szarzynska
authors.forename: Christian
authors.initials: C
authors.lastname: Fankhauser
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D055537:Light Signal Transduction; D018524:Phototropism / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins