Comparative transcript profiling of apricot (Prunus armeniaca L.) fruit development and on-tree ripening

摘要

Considering the high degree of sequence conservationudwithin the Rosaceae family and, in particular, amongudthe Prunus species, we employed the first available peachudoligonucleotide microarray (μPEACH 1.0) for studying theudtranscriptomic profile during apricot (cv. ‘Goldrich’) fruituddevelopment. Apricot fruits were harvested at three distinctuddevelopmental stages, corresponding to immature greenud(6 weeks before fully ripe stage), mature firm ripe (changeudof peel colour, 1 week before fully ripe stage) and fullyudripe, namely T1, T2 and T3, respectively. When applied toudμPEACH1.0, apricot target cDNAs showed significantudhybridization with an average of 43% of spotted probes,udvalidating the use of μPEACH1.0 to profile the transcriptomeudof apricot fruit. Microarray analyses carried outudseparately on peach (cv. ‘Fantasia’) and apricot fruit toudprofile transcriptome changes during fruit developmentudshowed that 70% of genes had the same expression patternudin both species. Such data indicate that the transcriptome isudquite similar in apricot and peach fruit and also highlightudthe presence of species-specific transcript changes. Inudapricot, 400 and 74 differentially expressed genes wereudfound during the transition from T1 to T2 and from T2 toudT3, respectively. Among these, a considerable number ofudgenes encoding IAA protein in action regulators (Aux/IAA)udand heat shock proteins (HSPs) were highly up-regulated atudearly and late ripening, respectively. Intriguingly, theudexpression profiles of all considered HSPs and some ofudIAA protein /IAA genes showed different patterns betweenudapricot and peach during the last stages of on-tree fruituddevelopment, suggesting the presence of diverse mechanismudregulating ripening in these two close phylogeneticallyudrelated species.