Location: Plant, Soil and Nutrition ResearchTitle: Differential metabolism of 1-phenylalaninein the formation of aromatic volatiles in melon (Cumis melo) fruit
|GONDA, ITAY - Agricultural Research Organization Of Israel|
|DAVIDOVICH-RIKANATI, RACHEL - Agricultural Research Organization Of Israel|
|BAR, EINAT - Agricultural Research Organization Of Israel|
|LEV, SHERRY - Agricultural Research Organization Of Israel|
|JHIRAD, PLIAA - Agricultural Research Organization Of Israel|
|TADMOR, YAAKOV - Agricultural Research Organization Of Israel|
|FEI, ZHANGJUN - Boyce Thompson Institute|
|KATZIR, NURIT - Agricultural Research Organization Of Israel|
|LEWINSOHN, EFRAIM - Agricultural Research Organization Of Israel|
Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2017
Publication Date: 3/15/2018
Citation: Gonda, I., Davidovich-Rikanati, R., Bar, E., Lev, S., Jhirad, P., Tadmor, Y., Giovannoni, J.J., Fei, Z., Katzir, N., Lewinsohn, E. 2018. Differential metabolism of 1-phenylalaninein the formation of aromatic volatiles in melon (Cumis melo) fruit. Phytochemistry. 16:296-305. https://doi.org/10.1017/S1479262117000314.
Interpretive Summary: The aroma of melon fruit is determined by the combination of hundreds of volatiles imparting both agreeable and disagreeable odors and constituting the full bouquet of flavors often associated with melon consumption. Melon is a very genetically diverse cultivated species and this diversity is also reflected in the different aromas displayed by the many varieties and accessions known. As is the case with many other fruits, melon volatiles are often derived from nutritionally important metabolites such as essential amino and fatty acids and carotenoi. In this context, aroma volatiles derived from amino acids are major contributors to the unique aroma of melons. Here we identify important genes in fruit volatile synthesis and demonstrate their contributions to melon aroma, a necessary aspect of high quality melon fruit.
Technical 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.