An integrative “omics” approach identifies new candidate genes to impact aroma volatiles in peach fruit

Abstract

BackgroundEver since the recent completion of the peach genome, the focus of genetic research in this area has turned to the identification of genes related to important traits, such as fruit aroma volatiles. Of the over 100 volatile compounds described in peach, lactones most likely have the strongest effect on fruit aroma, while esters, terpenoids, and aldehydes have minor, yet significant effects. The identification of key genes underlying the production of aroma compounds is of interest for any fruit-quality improvement strategy.ResultsVolatile (52 compounds) and gene expression (4348 genes) levels were profiled in peach fruit from a maturity time-course series belonging to two peach genotypes that showed considerable differences in maturation characteristics and postharvest ripening. This data set was analyzed by complementary correlation-based approaches to discover the genes related to the main aroma-contributing compounds: lactones, esters, and phenolic volatiles, among others. As a case study, one of the candidate genes was cloned and expressed in yeast to show specificity as an ω-6 Oleate desaturase, which may be involved in the production of a precursor of lactones/esters.ConclusionsOur approach revealed a set of genes (an alcohol acyl transferase, fatty acid desaturases, transcription factors, protein kinases, cytochromes, etc.) that are highly associated with peach fruit volatiles, and which could prove useful in breeding or for biotechnological purposes.

Breeding in peach, cherry and plum: from a tissue culture, genetic, transcriptomic and genomic perspective

“…These genome initiatives coupled with transcriptomic analyses of these fruit species are enabling scientists to identify candidate genes, signal transduction pathways and metabolic pathways that may play an important role in fruit quality and production (Gonzalez-Aguero et al, 2008;Tittarelli et al, 2009;Vizoso et al, 2009;Illa et al, 2011a;Alkio et al, 2012;Barakat et al, 2012;Diez-de-Medina and Silva, 2012;Dirlewanger et al, 2012;Habu et al, 2012;Leida et al, 2012;Trainotti et al, 2012;Koepke et al, 2013;Eduardo et al, 2013;Martinez-Garcia et al, 2013;Sanchez et al, 2013). Identifi cation of polymorphisms between members of the Rosaceae, members of the same genus (i.e.…”

Cartografiado de QTL y genes candidatos asociados a metabolitos determinantes de la calidad de fruto en melocotón

“…S5A). In the same way, the QTL controlling 2-Hexen-1-ol acetate (E)-falls in the same region of Cytochrome P450 homologs (ppa006310m) which we identified for being highly correlated to this compound (Sánchez et al, 2013).…”

“…Although, the most likely explanation for the cluster of QTL identified at the bottom of LG4 is two loci with pleiotropic effect, is also interesting to note that a delta 9 fatty acid desaturase (ppa009359m) which we identified as a putative candidate gene for being inversely correlated to Hexanal (Sánchez et al, 2013) co-localized with its QTL (Fig. S5A).…”

“…Peach volatile biosynthesis is highly dependent on the ripening stage of fruit Sánchez et al, 2013;. For that reason we also analyzed QTL for the main characteristics that have been traditionally used to asses maturity stage of the peach fruit (and therefore quality): flesh firmness, weight, SSC and peel color-related variables in order to compare the locus controlled by maturity with those controlling volatile production.…”

“…More recently, novel candidate genes for controlling diverse groups of volatiles were proposed by using a non-targeted genomic approach which analyzed the correlation between transcript and compound levels (Sánchez et al, 2013). Nowadays, a high-quality genome of peach is available and it is envisaged that next-generation sequencing technologies such as RNA-seq will be soon applied to discover more genes related to the aroma of peach.…”