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There is an increasing interest in polyphenols, plant secondary metabolites, in terms of fruit quality and diet, mainly due to their antioxidant effect. However, the identification of key gene enzymes and their roles in the phenylpropanoid pathway in temperate fruits species remains uncertain. Apricot (Prunus armeniaca) is a Mediterranean fruit with high diversity and fruit quality properties, being an excellent source of polyphenol compounds. For a better understanding of the phenolic pathway in these fruits, we selected a set of accessions with genetic-based differences in phenolic compounds accumulation. HPLC analysis of the main phenolic compounds and transcriptional analysis of the genes involved in key steps of the polyphenol network were carried out. Phenylalanine ammonia-lyase (PAL), dihydroflavonol-4-reductase (DFR) and flavonol synthase (FLS) were the key enzymes selected. Orthologous of the genes involved in transcription of these enzymes were identified in apricot: ParPAL1, ParPAL2, ParDFR, ParFLS1 and ParFLS2. Transcriptional data of the genes involved in those critical points and their relationships with the polyphenol compounds were analyzed. Higher expression of ParDFR and ParPAL2 has been associated with red-blushed accessions. Differences in expression between paralogues could be related to the presence of a BOXCOREDCPAL cis-acting element related to the genes involved in anthocyanin synthesis ParFLS2, ParDFR and ParPAL2.

No abstract

In a social context of increasingly concern about healthy diets, the development of new varieties with enhanced content in nutraceutical compounds is an increasingly important objective of the fruit breeding programs currently developed. In this sense, apricot is a fruit crop very appreciated by consumers due to its organoleptic characteristics, but also plays an important role in human nutrition due to its contain of phytocompounds as sugars, organic acids, vitamins and polyphenols. In this work, new selections from the apricot breeding program carried out at the Instituto Valenciano de Investigaciones Agrarias (IVIA) and traditional varieties have been analysed aimed at identifying sources of genetic variation for fruit quality. For this purpose, sugar content, organic acids and ascorbic acid were studied during two crop years. Results revealed sucrose and glucose as the major sugars, malic and citric acid as the main organic acids, and diverse ascorbic acid content among the cultivars studied. Results obtained pointed some accessions as potential sources to increase fruit quality. In addition, the study showed that apricot peel is an excellent source of nutraceutical compounds. Moreover, this study opens up new possibilities for future work to study the genetic control of these traits in apricot.

Aim of study: In a social context of increasing concern about healthy diets, the development of new varieties with enhanced content in nutraceutical compounds is an important objective of the fruit breeding programs currently developed. In this sense, apricot is a fruit crop very appreciated by consumers worldwide due to its organoleptic characteristics, but also plays an important role in human nutrition due to its content of phytocompounds as sugars, organic acids, vitamins and polyphenols. Area of study: The identification of sources of variation for these traits could be useful for apricot breeding worldwide. Material and methods: New selections from the apricot breeding program carried out at the Instituto Valenciano de Investigaciones Agrarias (IVIA, Spain) and traditional varieties have been analysed aimed at identifying sources of genetic variation for fruit quality. For this purpose, sugar content, organic acids and ascorbic acid were studied during three crop years. Main results: Results revealed sucrose and glucose as the major sugars, malic and citric acid as the main organic acids, and diverse ascorbic acid content among the cultivars studied. Research highlights: Some accessions point as potential sources to increase fruit quality. In addition, the study showed that apricot peel is an excellent source of nutraceutical compounds. Moreover, this study opens up new possibilities to study the genetic control of these traits in apricot in the future.