Publication

Journal	Plant Physiology
Volume (Issue)	161(3)
Page(s)	1066
Title of proceedings	Plant Physiology

URL	http://www.plantphysiol.org/cgi/pmidlookup?view=long&pmid=23355633
Type of Open Access	Publisher (Gold Open Access)

Cytokinins are classic plant hormones that orchestrate plant growth, development, and physiology. They affect gene expression in target cells by activating a multistep phosphorelay network. Type-B response regulators, acting as transcriptional activators, mediate the final step in the signaling cascade. Previously, we have introduced a synthetic reporter, TCS (Two Component signaling Sensor)::GFP, which reflects the transcriptional activity of type-B response regulators. TCS::GFP was instrumental in uncovering novel roles of cytokinin, and deepening our undestanding of existing functions. However, TCS-mediated expression of reporters is weak in some developmental contexts, where cytokinin signaling has a documented role, such as in the shoot apical meristem, or in the vasculature of Arabidopsis thaliana. In addition, we observed that GFP expression becomes rapidly silenced in TCS::GFP transgenic plants. Here, we present an improved version of the reporter, TCS new (TCSn), which, compared to TCS, is more sensitive to phosphorelay signaling in Arabidopsis and maize cellular assays, while retaining its specificity. Transgenic Arabidopsis TCSn::GFP plants exhibit strong and dynamic GFP expression patterns consistent with known cytokinin functions. In addition, GFP expression has been stable over generations, allowing crosses with different genetic backgrounds. Thus, TCSn represents a significant improvement to report the transcriptional output profile of phosphorelay signaling networks in Arabidopsis, maize, and likely other plants that display common response regulator DNA-binding specificities.