Project Number: 1907-21000-034-23
Project Type: Reimbursable

Start Date: Mar 01, 2011
End Date: Feb 28, 2013

Objective:
Available nutrient levels within many soils impose limits on overall plant productivity and yield. For food security, future agricultural practices will need to incorporate important traits for nutrient use efficiency to generate elite high-yielding crops. Although it has long been known that nutrient acquisition by the roots is controlled by root-to-shoot and shoot-to-root signaling systems, currently little is known regarding the molecular components that function in these pathways. Recently, analysis of phloem sap collected from plants subjected to nutrient deprivation, identified a number of small RNA species that may mediate in the epigenetic regulation of ion acquisition by the roots.

Approach:
To further explore this possibility, we plan to utilize the cucumber genome, in combination with our ability to collect analytical quantities of phloem sap from this species, to identify and characterize potential siRNA, miRNA and mRNA molecules involved in regulating nutrient acquisition by the root system. Next, we will identify the phloem proteins that deliver such candidate RNA species to the root, as well as the cells targeted for regulation. Finally, we plan to explore the gene regulatory network(s) that operates within these target tissues to allow plants to adapt to the ever changing nutrient availability within the soil. These studies will provide insights into the mechanisms that evolved to allow plants to coordinate nutrient acquisition by the root with developmental and physiological processes occurring within the above-ground regions of the plant. As an important outcome, this knowledge would contribute towards the engineering of crops having enhanced nutrient use efficiency.