The aroma biogenesis-related Olea europaea ALCOHOL DEHYDROGENASE gene is developmentally regulated in the fruits of two O. europaea L. cultivars

A survey of ethanol content in virgin olive oil

“…The level of ADH activity was also studied during the ripening process of five genotypes from the "Picual" x "Arbequina" cross ( Figure 4-B). As it happens to the two parents ("Picual" and "Arbequina"), an increase in the level of this enzymatic activity was observed during fruit ripening for all the genotypes under study in good agreement with what found by Iaria et al (2012) for the expression level of an olive ADH gene (OeADH). The confirmation of the natural presence of ethanol in VOO, and consequently in olive fruits, and of ADH activity would indirectly support the hypothesis of the PDH bypass working in the generation of TAG in olive fruit; this ADH activity acting as a safety valve against the synthesis of high levels of acetaldehyde, which produces ethanol.…”

The Alcohol Dehydrogenase Gene Family in Melon (Cucumis melo L.): Bioinformatic Analysis and Expression Patterns

“…Our research results also demonstrated that these melon ADH genes had very low sequence identity at protein level (ranging from 4.8 to 52.48%) and different intron-exon patterns at nucleotide level ( Figure 3 ). Up to the present, research on ADH in plants have been focused on the medium- and short- chain ADH superfamilies ( ManrÍquez et al, 2006 ; Kim et al, 2009 ; Singh et al, 2010 ; Iaria et al, 2012 ; Yamauchi et al, 2014 ; Chen et al, 2015 ). Furthermore, plant FDH, with hydroxylmethyl-glutathione or formaldehyde as preferred substrates, belonged to the medium-chain ADHs ( Strommer, 2011 ), while it is weakly active or inactive on n-octanol or ethanol ( Chase, 1999 ); Hence, in regard to substrate specifity, FDH was different from ADH1 in plant.…”

“…Additionally, these medium-chain CmADHs , divided into six subgroups ( Supplementary Figure S1 and S4 – S8 ), also suggested that it seems possible to be different substrate specificities among melon medium-chain ADH genes and to be the same with that of vertebrates in which the medium-chain ADHs clustered in different subgroups ( Duester et al, 1999 ). Hitherto, melon CmADH1 ( ManrÍquez et al, 2006 ), tomato Le-ADH2 and LeADH3 ( Speirs et al, 1998 ), mango MiADH1,2 ( Singh et al, 2010 ), grape Vv-ADH2 ( Tesniere et al, 2004 ) and olive OeADH ( Iaria et al, 2012 ), clustering a same class, belonged to the medium-chain zinc-binding type of ADHs ( Supplementary Figure S1 ), and in vitro , the functional verification results revealed that this type of plant ADHs were implicated in plant development, fruit ripening and aroma production, and response to stresses.…”

“…Sets of ADH genes or ADH-like genes have been identified in the genomes of poaceae, rosaceae, brassicaceae, fabaceae, and pinaceae plants ( Thompson et al, 2010 ; Zheng et al, 2011 ). So far, most members of the ADHs in plants characterized at the gene level belonged to the medium-chain ADH protein superfamily (including ADH1, EC 1.1.1.1 and FDH, Class III ADH, EC 1.2.1.1; Chase, 1999 ), which usually contains zinc ligands in their active site ( Tesnière and Verriès, 2000 ; Garabagi et al, 2005 ; ManrÍquez et al, 2006 ; Koutsompogeras et al, 2010 ; Singh et al, 2010 ; Komatsu et al, 2011 ; Pathuri et al, 2011 ; Bukh et al, 2012 ; Iaria et al, 2012 ; Min et al, 2012 ; Cheng F.F. et al, 2013 ), and the short-chain ADH protein superfamily, which lacks zinc-liganding cysteine residues in their coenzyme binding regions, and the molecular functions of only a few short-chain ADH genes were known ( ManrÍquez et al, 2006 ; Gonzalez-Agüero et al, 2009 ; Kim et al, 2009 ; Strommer, 2011 ; Moummou et al, 2012 ).…”

“…Previous studies highlighted that the medium-chain ADHs in plant were involved in response to abiotic and biotic stress which induced the specific expression of these ADHs in different tissues of soybean, wheat and barley, implying that they may participate in different tissues development in stresses ( Komatsu et al, 2011 ; Pathuri et al, 2011 ; Yamauchi et al, 2014 ). Moreover, regardless of medium- chain ADHs or short-chain ADHs, ADH genes have been shown to play a major role in fruit ripening and aroma synthesis ( Tesnière and Verriès, 2000 ; ManrÍquez et al, 2006 ; Singh et al, 2010 ; Zhang et al, 2011 ; Zheng et al, 2011 ; Bukh et al, 2012 ; Iaria et al, 2012 ; Moummou et al, 2012 ). However, the actual participation of medium-chain ADHs in aroma volatile production in vivo has been only clearly demonstrated in tomato fruit by over-expressing or down-regulating the LeADH2 gene ( Speirs et al, 1998 ).…”