Rohan Rattan Rose Hills
Temporal Dynamics of Cytokinin Signaling in Nicotiana Benthamiana
Plant development is regulated by hormones. A particularly important hormone controlling cell growth, division and differentiation in plants is cytokinin. Exposure to cytokinin is known to trigger the increase in the expression of hundreds of genes that reprogram the cell. However, these genes do not respond simultaneously. The cell carefully regulates the speed with which genes turn on after a stimulus. How do plants control the order and speed at which different cytokinin-responsive genes turn on in response to the hormone? To answer this, I plan to explore the temporal dynamics of cytokinin transcriptional response using transient expression of cytokinin-responsive reporter genes in the model species Nicotiana benthamiana. I will measure gene expression kinetics in response to a cytokinin stimulus using constructs that express fluorescent protein-based molecular timers. I hypothesize that the speed with which a given gene turns on after cytokinin exposure is cis-encoded at the level of its promoter sequence. Swapping promoter DNA regions between fast and slow responding genes will allow me to test this hypothesis. All in all, I hope to advance knowledge related to the mechanisms by which temporal dynamics are encoded by the cell and what their impact is on the cell’s response to cytokinin!