PostDoc Cold Spring Harbor Laboratory Cold SPring Harbor, New York
Body of Abstract: Nitrogen availability is vital for increase in crop production and overall plant development whereas excessive application of nitrogen can create nitrogen toxicity in plants and can lead to negative impacts on the environment. Nitrogen use efficiency is a complex trait, to study this we constructed a yeast one hybrid GRN for NUE in maize and used temporal expression patterns to profile the early response to nitrogen limitation and recovery in maize and sorghum. The Maize NUE GRN consists of 1625 protein DNA interactions (PDI); with 70 promoters and 301 transcriptional factors (TF). When comparing the Maize GRN to the previously reported Arabidopsis GRN; 35% of the PDIs were conserved among various nitrogen-related processes between both species, with three TF families display a high degree of connectivity in the GRN for ERF, bZIP, and MYB TF families. Additionally, the conservation is more in subnetworks associated with carbon metabolism and nitrate assimilation. The conservation observed between dicot and monocot, suggest the possibility of projection of these GRN to other species. Using the maize GRN, we were able to project a sorghum GRN, consisting of 1596 PDIs between 93 promoters and 226 TFs. To characterize subnetworks involved in response to nitrogen limitation and recovery, we were able to overlay time-series expression data from leaf and root samples grown hydroponically. Preliminary results indicated that the nitrogen-responsive genes in the two monocots display common PDI interactions but exhibit dissimilar patterns of temporal expression for conserved interactions in the nitrate assimilation subnetwork. Together, the conserved interaction highlights the response of nitrogen responsive genes to adapt to the availability of nitrogen while maintaining stability of the regulatory structure in crops. This GRN may provide critical insight into response to nitrogen regulation for agronomic and NUE improvements for major crop species.