Functional Versatility of Multi-Protein Mediator Complex in Plant Growth and Development

The eukaryotic multi-subunit Mediator complex coordinates between transcription activators/repressors and general transcription machinery to direct a rigid transcriptional regulation. In plants, investigations on the Mediator complex have gained pace recently. Several reports from Arabidopsis and other plants provide details of the structure and function of the Mediator complex/subunits. Plant Mediator complex subunits are encoded by multiple paralogous genes and form a complex network regulating diverse aspects of plant growth and development. Different subunits of the Mediator complex are shown to have diverse roles in shaping overall plant architecture and involve multiple hormonal signals. The critical role of the Mediator complex subunits is evident in both the vegetative and reproductive phases of plants. It also mediates metabolite homeostasis and non-coding RNA production. While functional conservation has been attributed to several subunits of the Mediator complex, diverse mechanistic aspects are also emerging. The integration of new knowledge greatly improves our understanding of the complexity of transcriptional control of different traits in plants.