Trichomes are single-celled epidermal hairs that help protect plants against herbivores, transpirational water loss, and UV irradiation. In Arabidopsis, trichomes exist on most aerial plant parts, including rosette leaves, stems, cauline leaves, and sepals, but not on hypocotyls and cotyledons. Several MYB transcription factors have been determined to function in trichome development via incorporation into this complex.
Prof. YU Diqiu and his team of Xishuangbanna Tropical Botanical Garden (XTBG) conducted a study to examine the role of MYB82, an R2R3-MYB transcription factor, in Arabidopsis trichome development. Most R2R3-MYB proteins have been characterized using genetic approaches and have been found to be involved in the control of plant-specific processes such as primary and secondary metabolism, cell fate and identity, developmental processes, and responses to biotic and abiotic stresses
The study focused on the function of MYB82 in trichome development and demonstrated that MYB82 functioned in the plant cell nucleus as a positive regulator. Although MYB82 loss of function did not disrupt trichome development, MYB82 overexpression led to abnormal trichome development. On the other hand, overexpression of MYB82-SRDX (fused with a dominant repression domain) or an N-terminal R2R3-MYB domain caused glabrous leaves. MYB82 driven by the GL1 promoter was able to rescue the glabrous phenotypes of the gl1 mutant, suggesting that the MYB82 protein was functionally equivalent to the GL1 protein. The MYB82 gene contained two introns, at least one of which was found to be crucial for MYB82 regulation of trichome development. The third exon of MYB82 contained a perfect MYB-binding box that was demonstrated to be also necessary for MYB82 function. Similar to GL1, MYB82 was able to interact with GL3, suggesting that MYB82 was incorporated into the WD40–bHLH–MYB complex to participate in the regulation of trichome development. In addition, the study revealed that MYB82 proteins can form homodimers or heterodimers with GL1 proteins.
The study entitled “MYB82 functions in regulation of trichome development in Arabidopsis” has been published online in Journal of Experimental Botany.
