Comparative transcriptome analysis between interspecific hybridization (Huaren apricot ♀ × almond ♂) and intraspecific hybridization (Huaren apricot) during young fruit developmental stage

Huaren apricot and almond are two tree species with nuts as the main economically important products. Crossbreeding these two species might be a good approach for combining the traits of large seed kernel of almond with the wide adaptability of Huaren apricot. However, the molecular mechanism of hybridization incompatibility between Huaren apricot and almond has remained unclear until date. In the present study the transcriptomes of developing fruits after interspecific hybridization between Huaren apricot and almond and after intraspecific hybridization of Huaren apricot were compared to elucidate the possible molecular mechanisms of fruit development at the gene expression level. Approximately 562,535,240 clean reads were assembled, and 25,692 unigenes were identified. Totally, 270 differentially expressed genes (DEGs) were identified, of which 221 were up-regulated and 49 were down-regulated in almond as compared with Huaren apricot. Functional annotation analysis indicated that the expression of cinnamyl alcohol dehydrogenase and EREBP were significantly up-regulated, whereas GA2ox and MADS were down-regulated in the intraspecific hybridization (PN) as compared with the interspecific hybridization (MN). Moreover, these genes might play an important role in fruit development. This study provides novel insights into the molecular mechanisms of fruit development in interspecific and intraspecific hybrids.