Characterization of the promoter and 5′-UTR intron of oleic acid desaturase (FAD2) gene in Brassica napus

In the present study, we characterized the transcriptional regulatory region (KF038144) controlling the expression of a constitutive FAD2 in Brassica napus. There are multiple FAD2 gene copies in B. napus genome. The FAD2 gene characterized and analyzed in the study is located on chromosome A5 and was designated as BnFAD2A5-1. BnFAD2A5-1 harbors an intron (1192bp) within its 5′-untranslated region (5′-UTR). This intron demonstrated promoter activity. Deletion analysis of the BnFAD2A5-1 promoter and intron through the β-glucuronidase (GUS) reporter system revealed that the −220 to −1bp is the minimum promoter region, while −220 to −110bp and +34 to +285bp are two important regions conferring high-levels of transcription. BnFAD2 transcripts were induced by light, low temperature, and abscisic acid (ABA). These observations demonstrated that not only the promoter but also the intron are involved in controlling the expression of the BnFAD2A5-1 gene. The intron-mediated regulation is an essential aspect of the gene expression regulation. •A transcriptional regulatory region controlling the expression of a FAD2 in Brassica napus was characterized.•BnFAD2A5-1 harbors an intron within its 5'-UTR. This intron demonstrated promoter activity.•Deletion analysis of the BnFAD2A5-1 promoter and intron revealed that the –220 to –1bp is the minimum promoter region, while –220 to –110bp and +34 to +285bp are two important regions conferring high-levels of transcription.•BnFAD2A5-1 transcripts can be induced by light, low temperature, and abscisic acid (ABA).