title: The R2R3-MYB-like regulatory factor EOBI, acting downstream of EOBII, regulates scent production by activating ODO1 and structural scent-related genes in petunia.
abstract: Flower scent is a highly dynamic trait, under developmental, spatial, and diurnal regulation. The mechanism governing scent production is only beginning to be unraveled. In petunia (Petunia hybrida), EMISSION OF BENZENOIDS II (EOBII) controls transcription of both the shikimate pathway-regulating MYB factor ODORANT1 (ODO1) and phenylpropanoid scent-related structural genes. A promoter-activation screen identified an R2R3-MYB-like regulatory factor of phenylpropanoid volatile biosynthesis acting downstream of EOBII, designated EOBI. EOBI silencing led to downregulation of ODO1 and numerous structural scent-related genes from both the shikimate and phenylpropanoid pathways. The ability of EOBI to directly activate ODO1, as revealed by electrophoretic mobility shift assay and yeast one-hybrid analysis, place EOBI upstream of ODO1 in regulating substrate availability for volatile biosynthesis. Interestingly, ODO1-silenced transgenic petunia flowers accumulated higher EOBI transcript levels than controls, suggesting a complex feedback loop between these regulatory factors. The accumulation pattern of EOBI transcript relative to EOBII and ODO1, and the effect of up/downregulation of EOBII on transcript levels of EOBI and ODO1, further support these factors' hierarchical relationships. The dependence of scent production on EOBI expression and its direct interaction with both regulatory and structural genes provide evidence for EOBI's wide-ranging involvement in the production of floral volatiles.
authors.affiliation: The Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
authors.forename: Ben
authors.initials: B
authors.lastname: Spitzer-Rimon
authors.forename: Moran
authors.initials: M
authors.lastname: Farhi
authors.forename: Boaz
authors.initials: B
authors.lastname: Albo
authors.forename: Alon
authors.initials: A
authors.lastname: Cna'ani
authors.forename: Michal Moyal
authors.initials: MM
authors.lastname: Ben Zvi
authors.forename: Tania
authors.initials: T
authors.lastname: Masci
authors.forename: Orit
authors.initials: O
authors.lastname: Edelbaum
authors.forename: Yixun
authors.initials: Y
authors.lastname: Yu
authors.forename: Elena
authors.initials: E
authors.lastname: Shklarman
authors.forename: Marianna
authors.initials: M
authors.lastname: Ovadis
authors.forename: Alexander
authors.initials: A
authors.lastname: Vainstein
mesh_terms: D018506:Gene Expression Regulation, Plant; D009812:Odorants; D032306:Petunia / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins