title: Two showy traits, scent emission and pigmentation, are finely coregulated by the MYB transcription factor PH4 in petunia flowers.
abstract: The mechanism underlying the emission of phenylpropanoid volatiles is poorly understood. Here, we reveal the involvement of PH4, a petunia MYB-R2R3 transcription factor previously studied for its role in vacuolar acidification, in floral volatile emission. We used the virus-induced gene silencing (VIGS) approach to knock down PH4 expression in petunia, measured volatile emission and internal pool sizes by GC-MS, and analyzed transcript abundances of scent-related phenylpropanoid genes in flowers. Silencing of PH4 resulted in a marked decrease in floral phenylpropanoid volatile emission, with a concurrent increase in internal pool levels. Expression of scent-related phenylpropanoid genes was not affected. To identify putative scent-related targets of PH4, we silenced PH5, a tonoplast-localized H(+) -ATPase that maintains vacuolar pH homeostasis. Suppression of PH5 did not yield the reduced-emission phenotype, suggesting that PH4 does not operate in the context of floral scent through regulation of vacuolar pH. We conclude that PH4 is a key floral regulator that integrates volatile production and emission processes and interconnects two essential floral traits - 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: 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: Ben
authors.initials: B
authors.lastname: Spitzer-Rimon
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: Department of Plant Biology, University of California, Davis, CA, 95616, USA.
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: 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: 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: Marianna
authors.initials: M
authors.lastname: Ovadis
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 / Q000378:metabolism*; D020868:Gene Silencing; D032306:Petunia / Q000378:metabolism*; D010858:Pigmentation / Q000502:physiology*; D010940:Plant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D055549:Volatile Organic Compounds / Q000378:metabolism*
chemical_list: D010940:Plant Proteins; D014157:Transcription Factors; D055549:Volatile Organic Compounds
keywords: MYB; emission; floral scent; pH; petunia; phenylpropanoid; volatile