title: Insights into the Sesquiterpenoid Pathway by Metabolic Profiling andDe novoTranscriptome Assembly of Stem-Chicory (Cichorium intybusCultigroup "Catalogna").
abstract: Stem-chicory of the "Catalogna" group is a vegetable consumed for bitter-flavored stems. Type and levels of bitter sesquiterpene lactones (STLs) participate in conferring bitterness in vegetables. The content of lactucin-and lactucopocrin-like STLs was higher in "Molfettese" than "Galatina" landrace stalks, regardless of the cultivation sites, consistently with bitterness scores and gustative differences. The "Galatina" transcriptome assembly resulted in 58,872 unigenes, 77% of which were annotated, paving the way to molecular investigation of the STL pathway. Comparative transcriptome analysis allowed the identification of 69,352 SNPs and of 1640 differentially expressed genes that maintained the pattern independently of the site. Enrichment analyses revealed that 4 out of 29 unigenes were up-regulated in "Molfettese" vs "Galatina" within the sesquiterpenoid pathway. The expression of twogermacrene A-synthase(GAS) and one -oxidase(GAO) genes of the costunolide branch correlated positively with the contents of lactucin-like molecules, supporting that STL biosynthesis regulation occurs at the transcriptional level. Finally, 46 genes encoding transcription factors (TFs) maintained a differential expression pattern between the two varieties regardless of the growth site; correlation analyses amongTFs, GAS, GAOgene expressions and STLs contents suggest that oneMYBand onebHLHmay act in the pathway.
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Testone
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Mele
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Di Giacomo
authors.affiliation: Institute of Sciences of Food Production, National Research Council Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Gonnella
authors.affiliation: Institute of Sciences of Food Production, National Research CouncilBari, Italy; Department of Agricultural and Environmental Science, University of BariBari, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Renna
authors.affiliation: Department of Pharmacy, University of Naples Federico II Naples, Italy.
authors.forename: Gian Carlo
authors.initials: GC
authors.lastname: Tenore
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Nicolodi
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Frugis
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Maria Adelaide
authors.initials: MA
authors.lastname: Iannelli
authors.affiliation: Enza Zaden Italia Tarquinia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Arnesi
authors.affiliation: Enza Zaden Italia Tarquinia, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Schiappa
authors.affiliation: Institute of Agricultural Biology and Biotechnology, National Research Council Rome, Italy.
authors.forename: Donato
authors.initials: D
authors.lastname: Giannino
keywords: Cichorium intybus; bitterness; sesquiterpene lactones; stem-chicory landraces; transcriptome