title: GA as a regulatory link between the showy floral traits color and scent.
abstract: Emission of volatiles at advanced stages of flower development is a strategy used by plants to lure pollinators to the flower. We reveal that GA negatively regulates floral scent production in petunia. We used Agrobacterium-mediated transient expression of GA-20ox in petunia flowers and a virus-induced gene silencing approach to knock down DELLA expression, measured volatile emission, internal pool sizes and GA levels by GC-MS or LC-MS/MS, and analyzed transcript levels of scent-related phenylpropanoid-pathway genes. We show that GA has a negative effect on the concentrations of accumulated and emitted phenylpropanoid volatiles in petunia flowers; this effect is exerted through transcriptional/post-transcriptional downregulation of regulatory and biosynthetic scent-related genes. Both overexpression of GA20-ox, a GA-biosynthesis gene, and suppression of DELLA, a repressor of GA-signal transduction, corroborated GA's negative regulation of floral scent. We present a model in which GA-dependent timing of the sequential activation of different branches of the phenylpropanoid pathway during flower development may represent a link between the showy traits controlling pollinator attraction, namely color and scent.
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Jasmin
authors.initials: J
authors.lastname: Ravid
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Ben
authors.initials: B
authors.lastname: Spitzer-Rimon
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Takebayashi
authors.affiliation: RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, 230-0045, Japan.
authors.forename: Mitsunori
authors.initials: M
authors.lastname: Seo
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Alon
authors.initials: A
authors.lastname: Cna'ani
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Javiera
authors.initials: J
authors.lastname: Aravena-Calvo
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Tania
authors.initials: T
authors.lastname: Masci
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Moran
authors.initials: M
authors.lastname: Farhi
authors.affiliation: Institute of Plant Sciences and Genetics in Agriculture, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, PO Box 12, Rehovot, Israel.
authors.forename: Alexander
authors.initials: A
authors.lastname: Vainstein
mesh_terms: D035264:Flowers / Q000254:growth & development / Q000378:metabolism / Q000502:physiology; D020868:Gene Silencing; D005875:Gibberellins / Q000378:metabolism / Q000494:pharmacology* / Q000502:physiology; D032306:Petunia / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D005875:Gibberellins; D010937:Plant Growth Regulators; C007842:gibberellic acid
keywords: 
  GA
  ; floral scent; petunia; phenylpropanoid; showy trait; volatile