Monitoring Fruit Growth and Development in Apricot (Prunus armeniaca L.) through Gene Expression Analysis

The main objective of this study was to monitor apricot development and ripening through gene expression analysis of key candidate genes using the RT-qPCR technique. Eight apricot cultivars were selected to analyze phenological and genetic patterns from pre-ripening stages through to postharvest. In addition, 19 selected genes were analyzed in the contrasting cultivars 'Cebas Red' and 'Rojo Pasión' in different stages (two preharvest stages S1 and S2, one harvest stage S3, and two postharvest stages S4 and S5). This pool of genes included genes related to fruit growth and ripening, genes associated with fruit color, and genes linked to the fruit's nutraceutical aspects. Among the studied genes, <i>Polygalacturonase</i> (<i>PG</i>), <i>Pectin methylesterase</i> (<i>PME</i>), <i>Aminocyclopropane-1-carboxylate synthase</i> (<i>ACS</i>), and <i>Myo-inositol-1-phosphate synthase</i> (<i>INO1</i>) were directly related to fruit maturation and quality. Significant differential expression was observed between the cultivars, which correlated with variations in firmness, shelf life, and sensory characteristics of the apricots. 'Rojo Pasión' displayed high levels of <i>PG</i>, associated with rapid maturation and shorter postharvest shelf life, whereas 'Cebas Red' exhibited lower levels of this gene, resulting in greater firmness and extended shelf life. Genes <i>CCD4</i>, <i>CRTZ</i>, and <i>ZDS</i>, related to carotenoids, showed varied expression patterns during growth and postharvest stages, with higher levels in 'Rojo Pasión'. On the other hand, <i>Sucrose synthase</i> (<i>SUSY</i>) and <i>Lipoxygenase</i> (<i>LOX2</i>) were prominent during the postharvest and growth stages, respectively. Additionally, <i>GDP-L-galactose phosphorylase</i> (<i>VTC2_5</i>) was linked to better postharvest performance. This research provides valuable insights for future breeding initiatives aimed at enhancing the quality and sustainability of apricot cultivation.