Buckwheat R2R3 MYB transcription factor FeMYBF1 regulates flavonol biosynthesis

Efficient transient gene expression system using buckwheat hypocotyl protoplasts for large-scale experiments

“…FeMYBF1 activated reporter gene expression driven by the FeCHS, FeFLS, FeFLS1, FeFLS2, and FeANS promoters to varying extents (Fig. 5), which is similar to the result obtained in a previous study (Matsui et al 2018a). Interestingly, while FeDFR1a promoter activity in buckwheat protoplasts was induced only 1.58-fold and less than FeFLSs promoters by FeMYBF1, that in Arabidopsis mesophyll protoplasts was induced more than 10-fold and higher than the activation of FeFLSs reporter activity by FeMYBF1 (Matsui et al 2018a).…”

“…5), which is similar to the result obtained in a previous study (Matsui et al 2018a). Interestingly, while FeDFR1a promoter activity in buckwheat protoplasts was induced only 1.58-fold and less than FeFLSs promoters by FeMYBF1, that in Arabidopsis mesophyll protoplasts was induced more than 10-fold and higher than the activation of FeFLSs reporter activity by FeMYBF1 (Matsui et al 2018a). Agius et al (2005) reported that a heterologous promoter does not necessarily function in different plants due to differences in the regulatory mechanism.…”

“…This study presents an efficient transient gene expression system using buckwheat protoplasts, which is applicable to a large-scale experiment. Although most functional analyses of buckwheat transcrip- tion factors have been carried out to prepare transgenic Arabidopsis (Matsui et al 2018a, Yao et al 2017, at least two months are required to perform the analysis. Furthermore, heterologous expression between Arabidopsis and buckwheat may cause difficulties.…”

“…4). In addition, Gal4DB-FeMYBF1, which is a R2R3 MYB family transcription factor suggested to be a possible transcriptional activator for flavonol biosynthesis in buckwheat (Matsui et al 2018a), also significantly activated the same reporter activity (n = 4). The relative SD calculated by SD/mean in each experiment was 0.20 (control), 0.11 (Gal4DB-VP16), 0.37 (Gal4DB-SRDX), and 0.22 (Gal4DB-FeMYBF1), which is acceptable for a transient effector-reporter experiment.…”

“…Recent advances in sequencing technology have stimulated buckwheat genomic research. Yasui et al (2016) constructed the Buckwheat Genome Data Base (http://buckwheat.kazusa.or.jp/), which has been used to detect genes controlling important agronomical traits (Katsu et al 2017, 2018a, 2018b, Takeshima et al 2019. However, molecular Communicated by Ryo Ohsawa Received May 27, 2019.…”