Characterization of Arabidopsis MYB transcription factor gene AtMYB17 and its possible regulation by LEAFY and AGL15.

MYB transcription factors compose one of the largest transcription factor families in Arabidopsis, which play important roles in various developmental processes as well as defense responses against environmental stresses. In this study, we report the characterization of AtMYB17 gene, a putative R2R3 type MYB gene family member in Arabidopsis. AtMYB17 was found exclusively localized in nuclear, with an activation domain at its C-terminus. AtMYB17 was highly expressed in inflorescences and siliques, especially at early flower developmental stages. The level of AtMYB17 transcripts was also found to increase after imbibition during seed germination and gradually concentrate to the shoot apex. Bioinformatics analysis identified several binding sites of LEAFY (LFY) and AGL15 in the promoter region of AtMYB17. Promoter-GUS fusion analysis showed that the LFY binding sites were important in fine-tuning regulation of the spatio-temporal expression of AtMYB17 in transgenic plants. Moreover, AtMYB17 was up-regulated in 35S::AGL15 plants. Taken together, our data suggest that LFY may be involved in the regulation of AtMYB17, possibly together with AGL15, and thereafter in early inflorescence development and seed germination.