Cloning and Functional Analysis of <i>BcMYB101</i> Gene Involved in Leaf Development in Pak Choi (<i>Brassica rapa</i> ssp. <i>Chinensis</i>)

• Main Authors: Hualan Hou, Changwei Zhang, Xilin Hou
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: International Journal of Molecular Sciences
• Subjects: GAMYB; leaf development; pak-choi; <i>BcMYB101</i>; GA; trans-activation activity
• Online Access: https://www.mdpi.com/1422-0067/21/8/2750
• ISSN: 1661-6596; 1422-0067

As one of the largest transcription factor families, MYB transcription factors are widely present, and they are involved in a diverse range of physiological activities in plants, such as leaf development. GAMYB genes belong to the R2R3-MYB subfamily, which includes the <i>MYB33</i>/<i>65</i>/<i>101</i> gene, and these genes are studied well in seed germination and flowering, but their roles in leaf development are poorly understood. In the current study, we isolated a GAMYB transcription factor from pak choi, <i>BcMYB101</i>, and analyzed its characteristics and function. The sequence structure analysis indicated that <i>BcMYB101</i> has a highly conserved R2R3 DNA-binding domain in the N-terminal region and three GAMYB-specific motifs (Box1, Box2, and Box3). The expression pattern of diverse tissues revealed that <i>BcMYB101</i> has a higher transcript level in the petiole, leaf, root, and floral organs. Furthermore, the expression level was significantly elevated after GA (gibberellin) treatment, suggesting that the <i>BcMYB101</i> response was positively regulated by GA. Subcellular localization exhibited that <i>BcMYB101</i> was only present in the nuclear region, consistent with the characterization of the transcription factor. The overexpression of <i>BcMYB101</i> elucidated that <i>BcMYB101</i> increased leaf number and resulted in downward-curling cauline leaves. Moreover, the virus-induced <i>BcMYB101</i> silencing displayed that <i>BcMYB101</i> is involved in the regulation of curly leaves. Furthermore, we discovered that <i>BcMYB101</i> has two trans-activation activities and one interaction protein, <i>BcTCH4</i>, using a trans-activation activity assay and a yeast two-hybrid assay, respectively. In this study, we firstly isolated the <i>BcMYB101</i> gene and explored its function in leaf development, thereby providing a solid foundation for further research on the regulatory mechanism of leaf shape in <i>Brassica</i> or other species.