Comparative transcriptomic analysis of flowering induction in pitaya induced by supplementary lighting

Background Pitayas are currently attracting considerable interest as a fruit with many health benefits. However, the lack of natural light after November in Hainan, China, severely restricts the production of pitaya in winter. To further explore the molecular mechanisms regulating flowering in pitaya, we used de novo RNA sequencing-based transcriptomic analysis for four stages of pitaya subjected to light induction. Results We assembled 68113 unigenes in total, comprising 29782 unigenes with functional annotations in the NR database, 20716 annotations in SwissProt, 18088 annotations in KOG, and 11059 annotations in KEGG. Comparison between different samples revealed different numbers of significantly differentially expressed genes (DEGs). A number of DEGs involved in energy metabolism-related processes and plant hormones were detected. Moreover, we discovered many CONSTANS-LIKE, FLOWERING LOCUS T and other DEGs involved in direct regulation of flowering, along with CDF and TCP, which function as typical transcription factor genes in the flowering process. At the transcriptomic level, we confirmed 13 DEGs with different functions in the time-course response to light-induced flowering by quantitative reverse-transcription PCR analysis. Conclusions These DEGs may include some key genes that control the floral-induction network, increasing our understanding of the molecular mechanism of floral regulation in pitaya. These findings will also aid the development of biotechnologies aimed at creating a variant of pitaya that is less sensitive to light conditions and blooms throughout the year.