Differential metabolism of L–phenylalanine in the formation of aromatic volatiles in melon (Cucumis melo L.) fruit. (April 2018)

• Record Type: Journal Article
• Authors: Gonda, Itay; Davidovich-Rikanati, Rachel; Bar, Einat; Lev, Shery; Jhirad, Pliaa; Meshulam, Yuval; Wissotsky, Guy; Portnoy, Vitaly; Burger, Joseph; Schaffer, Arthur A.; Tadmor, Yaakov; Giovannoni, James J.; Fei, Zhangjun; Fait, Aaron; Katzir, Nurit; Lewinsohn, Efraim
• Is Part Of: Phytochemistry. Volume 148(2018)
• Page Start: 122
• Page End: 131
• Publication Date: 2018-04
• Subjects: Cucumis melo L. -- Cucurbitaceae -- Melon -- L-phenylalanine metabolism -- Phenylpropanoid aroma volatiles -- (E)-cinnamic acid:coenzyme A ligase -- Benzoic acid:S-adenosyl-L-methionine carboxyl methyltransferase -- (E)-cinnamaldehyde -- Methyl benzoate; AAT alcohol acyl-transferase -- BAMT S-adenosyl-L-methionine: benzoic acid carboxyl methyltransferase -- CCR cinnamoyl-CoA reductase -- CNL (E)-cinnamic acid-CoA ligase -- CoA coenzyme A -- PAL L-phenylalanine ammonia-lyase -- PPP phenylpropanoid pathway -- RIL recombinant inbred line -- SAM S-adenosyl-L-methionine; Botanical chemistry -- Periodicals; Biochemistry -- Periodicals; Botany -- Periodicals; Chimie végétale -- Périodiques; 572.2
• DOI: 10.1016/j.phytochem.2017.12.018
• Languages: English
• ISSNs: 0031-9422

Abstract

Abstract: Studies on the active pathways and the genes involved in the biosynthesis of L-phenylalanine-derived volatiles in fleshy fruits are sparse. Melon fruit rinds converted stable-isotope labeled L-phe into more than 20 volatiles. Phenylpropanes, phenylpropenes and benzenoids are apparently produced via the well-known phenylpropanoid pathway involving phenylalanine ammonia lyase (PAL) and being ( E )-cinnamic acid a key intermediate. Phenethyl derivatives seemed to be derived from L-phe via a separate biosynthetic route not involving ( E )-cinnamic acid and PAL. To explore for a biosynthetic route to ( E )-cinnamaldehyde in melon rinds, soluble protein cell-free extracts were assayed with ( E )-cinnamic acid, CoA, ATP, NADPH and MgSO4, producing ( E )-cinnamaldehyde in vitro . In this context, we characterized CmCNL, a gene encoding for ( E )-cinnamic acid:coenzyme A ligase, inferred to be involved in the biosynthesis of ( E )-cinnamaldehyde. Additionally we describe CmBAMT, a SABATH gene family member encoding a benzoic acid: S -adenosyl-L-methionine carboxyl methyltransferase having a role in the accumulation of methyl benzoate. Our approach leads to a more comprehensive understanding of L-phe metabolism into aromatic volatiles in melon fruit. Graphical abstract: Highlights: L-phenylalnine is catabolized into 21 phenolic volatiles in melon ( C. melo ) fruit. Melons phenolic volatiles are produced via both PAL-dependent and PAL–independent pathways. C. melo cell-free extracts support ( E )-cinnamaldehyde formation from ( E )-cinnamic acid. C. melo ( E )-cinnamic acid:CoA ligase (CmCNL) supports cinnamoyl CoA production. C. melo benzoic acid O -methyltransferase (CmBAMT) supports methyl benzoate formation.