第988回 生物科学セミナー

Auxin acts as a hierarchical self-organizing signal in plants

Dr. Zhenbiao Yang(Professor,University of California Riverside)

2014年05月02日(金)    15:00~   理学部2号館 講堂   

Auxin regulates plant growth and development at all developmental stages. The TIR1/AFB-based auxin signaling pathway that regulates auxin-induced gene expression has been well established, but this pathway does not account for the action of auxin that is independent of transcriptional regulation. The mechanisms underlying the non-transcriptional auxin responses are poorly characterized, and the relationship between the transcriptional and non-transcriptional auxin signaling pathways is unknown. We have been using Arabidopsis leaf pavement cells as a model system to investigate the mechanisms of auxin action. Pavement cells develop interdigitated lobes and indentation to form puzzle piece cell shape. Auxin is required and sufficient for the formation of the pavement cell interdigitation. We recently found that this process is regulated by the cytoplasmic auxin signaling pathways that require auxin binding protein 1 (ABP1) and ROP GTPases. These pathways interact with each other in a self-organizing manner to locally coordinate the formation of interdigitated lobes and indentations within and between pavement cells. In addition, the TIR1-based transcriptional auxin signaling pathway is required for the generation of a global auxin signal that coordinate pavement cell morphogenesis throughout the entire leaf epidermis. These findings support the notion that auxin acts as a self-organizing hierarchical signal to regulate the patterning of pavement cells.