Transcriptome analysis of peach [Prunus persica (L.) Batsch] stigma in response to low-temperature stress with digital gene expression profiling

The peach [Prunus persica (L.) Batsch] is an important fruit crop that is prone to injury during spring frost, yet little is known about the molecular mechanism of the low temperature (LT) stress response in the peach. In this study, we employed next generation sequencing-technology to characterize the transcriptome of the peach stigma and identify differentially expressed genes (DEGs) of peaches treated at LT (−2 °C) for 4 and 26 h. We obtained a total of 31,273,923 (CK), 37,477,875 (S1), and 36,009,843 (S2) perfect reads from controls, 4 h LT treatment, and 26 h LT treatment, respectively. 96.4–96.8 % of the reads mapped to the peach genome. Gene ontology and pathway enrichment analysis revealed that the upregulated DEGs were predominately involved in response to temperature stimulus, carbohydrate metabolism, biological processes, cytoskeletal, hydrolase activity and primary metabolic pathways. Many of the genes coded for proteins involved in response to LT-associated mechanisms, including the U-box domain-containing protein, CBL-interacting protein kinase, NAC domain-containing protein, and dehydration-responsive element-binding protein. More genes were differentially expressed in S2 (966) compared to S1 (276), and of these, the U-box domain-containing protein 34 had the highest expression in S2. Furthermore, we confirmed differential expression of 20 selected genes via qPCR and found highly similar expression differences to the Illumina analysis. Overall, we identified candidate genes for LT stress in the peach and provide new insights for investigating the molecular mechanisms of LT stress.