Transcriptomics-based identification and characterization of glucosyltransferases involved in betalain biosynthesis in Hylocereus megalanthus

• Published in: Plant physiology and biochemistry Vol. 152; pp. 112 - 124
• Main Authors: Xie, Fangfang, Hua, Qingzhu, Chen, Canbin, Zhang, Lulu, Zhang, Zhike, Chen, Jianye, Zhang, Rong, Zhao, Junsheng, Hu, Guibing, Zhao, Jietang, Qin, Yonghua
• Format: Journal Article
• Language: English
• Published: France Elsevier Masson SAS 01.07.2020
• Subjects: Pitaya transcriptome analysis betalain biosynthesis glucosyltransferases; Pitaya transcriptome analysis betalain biosynthesis glucosyltransferases
• ISSN: 0981-9428; 1873-2690
• DOI: 10.1016/j.plaphy.2020.04.023

Pitaya (Hylocereus spp.) is the only commercial cultivation of fruit containing abundant betalains for consumer. Betalains are water-soluble nitrogen-containing pigments with high nutritional value and bioactivities. In this study, contents of betaxanthins and betacyanins were compared between ‘Guanhuabai’ (H. undatus) and ‘Huanglong’ (H. megalanthus) pitayas and key genes involved in betalain biosynthesis were screened from ‘Huanglong’ pitaya by RNA-Seq technology. Twenty-nine candidate genes related to betalain biosynthesis were obtained from the transcriptome data. Based on expression characteristics and sequence analyses, HmB5GT1 and HmHCGT2 were further analyzed. HmB5GT1 and HmHCGT2 were both conserved in ‘PSPG-box’ and localized in nucleus. Silencing of HmB5GT1 and HmHCGT2 resulted in a significant reduction in betacyanin and betaxanthin contents. Those results suggested that HmB5GT1 and HmHCGT2 are possibly involved in betalain biosynthesis in H. megalanthus. The present work provides new information on betalain biosynthesis in Hylocereus at the transcriptional level. •Twenty-nine candidate genes involved in betalain biosynthesis were obtained from transcriptome data of H. megalanthus.•HmB5GT1 and HmHCGT2 were conserved in ‘PSPG-box’ and localized in nucleus.•Silencing of HmB5GT1 and HmHCGT2 resulted in a significant reduction in betalain contents.•HmB5GT1 and HmHCGT2 play key roles in the betalain biosynthesis in pitaya.