title: PIF genes mediate the effect of sucrose on seedling growth dynamics.
abstract: As photoautotrophs, plants can use both the form and amount of fixed carbon as a measure of the light environment. In this study, we used a variety of approaches to elucidate the role of exogenous sucrose in modifying seedling growth dynamics. In addition to its known effects on germination, high-resolution temporal analysis revealed that sucrose could extend the number of days plants exhibited rapid hypocotyl elongation, leading to dramatic increases in ultimate seedling height. In addition, sucrose changed the timing of daily growth maxima, demonstrating that diel growth dynamics are more plastic than previously suspected. Sucrose-dependent growth promotion required function of multiple phytochrome-interacting factors (PIFs), and overexpression of PIF5 led to growth dynamics similar to plants exposed to sucrose. Consistent with this result, sucrose was found to increase levels of PIF5 protein. PIFs have well-established roles as integrators of response to light levels, time of day and phytohormone signaling. Our findings strongly suggest that carbon availability can modify the known photomorphogenetic signaling network.
authors.affiliation: Department of Biology, University of Washington, Seattle, Washington, United States of America.
authors.forename: Jodi L
authors.initials: JL
authors.lastname: Stewart
authors.forename: Julin N
authors.initials: JN
authors.lastname: Maloof
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Nemhauser
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D018525:Germination / Q000187:drug effects; D018546:Hypocotyl / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D008027:Light; D010834:Phytochrome / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D013395:Sucrose / Q000494:pharmacology*
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D010834:Phytochrome; D012333:RNA, Messenger; D018749:RNA, Plant; D013395:Sucrose; C508068:At2g20180 protein, Arabidopsis; C497729:PIF5 protein, Arabidopsis