Seminar

Structural Biology of Plant Salt Tolerance

Armando Albert, PhD

Due to their sessile nature, plants have to endure adverse environmental conditions. Among them, drought and salinity constrain agricultural productivity most dramatically. At molecular level, the abscisic acid (ABA) together with calcium regulates many of the stress adaptive plant processes. The plant PYR family of protein abscisic acid (ABA) receptors, their interacting protein phosphatase type 2C substrates (PP2C) and a group of protein kinases (SnRK2 and SnRK3) act together in decoding ABA and calcium signals elicited by different environmental stimuli. The pathway provides all the elements to regulate the cell response by the phosphorylation of various ion transporters and transcription factors. As a result, the balance between the negative PP2C or positive SnRK2/3 regulators fine tune the cell response in an ABA and/or calcium dependent manner. SnRK2 and SnRK3 have evolved to display discrete scaffold modules that organize these signaling proteins into supramolecular complexes. These arrangements are involved in the regulation of the activity of its components, increase the specificity of the signal and sometimes, ensure the co-localization of the substrates and the products in a particular cellular place. To understand these issues, it is necessary to describe the molecular architecture of the interaction among the members of the network and the substrates channels, and to characterize the effect of calcium and ABA on these interactions.