Fruit Phenolic Profiling: A New Selection Criterion in Olive Breeding Programs

Abstract

Olive growing is mainly based on traditional varieties selected by the growers across the centuries. The few attempts so far reported to obtain new varieties by systematic breeding have been mainly focused on improving the olive adaptation to different growing systems, the productivity and the oil content. However, the improvement of oil quality has rarely been considered as selection criterion and only in the latter stages of the breeding programs. Due to their health promoting and organoleptic properties, phenolic compounds are one of the most important quality markers for Virgin olive oil (VOO) although they are not commonly used as quality traits in olive breeding programs. This is mainly due to the difficulties for evaluating oil phenolic composition in large number of samples and the limited knowledge on the genetic and environmental factors that may influence phenolic composition. In the present work, we propose a high throughput methodology to include the phenolic composition as a selection criterion in olive breeding programs. For that purpose, the phenolic profile has been determined in fruits and oils of several breeding selections and two varieties (“Picual” and “Arbequina”) used as control. The effect of three different environments, typical for olive growing in Andalusia, Southern Spain, was also evaluated. A high genetic effect was observed on both fruit and oil phenolic profile. In particular, the breeding selection UCI2-68 showed an optimum phenolic profile, which sums up to a good agronomic performance previously reported. A high correlation was found between fruit and oil total phenolic content as well as some individual phenols from the two different matrices. The environmental effect on phenolic compounds was also significant in both fruit and oil, although the low genotype × environment interaction allowed similar ranking of genotypes on the different environments. In summary, the high genotypic variance and the simplified procedure of the proposed methodology for fruit phenol evaluation seems to be convenient for breeding programs aiming at obtaining new cultivars with improved phenolic profile.

An Aromatic Aldehyde Synthase Controls the Synthesis of Hydroxytyrosol Derivatives Present in Virgin Olive Oil

“…Response factors were calculated for each phenolic compound. Identification of compounds was confirmed by HPLC/ESI-qTOF-HRMS on a liquid chromatograph Dionex Ultimate 3000 RS U-HPLC liquid chromatograph system (Thermo Fisher Scientific, Waltham, MA, USA) equipped with a similar column and elution program [33]. Mass spectra were acquired in MS fullscan mode and data were processed using TargetAnalysis 1.2 software (Bruker Daltonics, Bremen, Germany).…”

Analysis of Olive (Olea Europaea L.) Genetic Resources in Relation to the Content of Vitamin E in Virgin Olive Oil

“…To do this, cultivars may be selected from the vast genetic pool that already exist or may be generated from the crossing of cultivars that are characterized by exhibiting a particular phenotype. Thus, in addition to traditional agronomic traits [18], the functional quality of VOO has been considered lately as a target of breeding programs that aim to obtain new olive cultivars [19,20,21]. With this in mind, the purpose of the present research was to conduct a study of the vitamin E content in olive.…”

Two bi-functional cytochrome P450 CYP72 enzymes from olive (Olea europaea) catalyze the oxidative C-C bond cleavage in the biosynthesis of secoxy-iridoids - flavor and quality determinants in olive oil

“…It has been hypothesized that domestication of olive was driven by gene expression, rather than genomic changes (Gros-Balthazard et al, 2019). It has also been reported that secoiridoid contents are mainly controlled by the cultivar genotype (Miho et al, 2018;Pérez et al, 2018;Deiana et al, 2019). Notably, published transcriptomic datasets for olive have shown that OeOMES expression is not substantially increased by environmental stresses, but is more highly expressed in domesticated versus wild olives.…”

“…Obtaining olive varieties with "fine-tuned" oleuropein levels is an important goal of olive breeding programs (Pérez et al, 2018). The benefits of secoiridoid-related markers have been recently highlighted in the industrial processing of table olives, where oleuropein degradation via glucosidases was a major biochemical marker for strain selection (Bavaro et al, 2017).…”

“…The benefits of secoiridoid-related markers have been recently highlighted in the industrial processing of table olives, where oleuropein degradation via glucosidases was a major biochemical marker for strain selection (Bavaro et al, 2017). The importance of secoiridoids in systematic breeding of olive for quality Virgin Olive Oil is increasingly being recognized, with lack of knowledge on their genetic determinants as the major hurdle for this cause (Pérez et al, 2018). Since genotype appears to be a stronger determinant of secoiridoid contents than environmental conditions (Pérez et al, 2018), identification of the genes responsible for oleuropein biosynthesis could readily benefit the olive oil industry as a molecular marker.…”