Protein-Protein Interactions Involved in Water Transport in Cotton Roots

Down-regulation of aquaporin genes in plant roots in response to water-deficit and salt stress has been reported in many systems including corn, rice, and cotton. Since aquaporins passively aid water movement, we speculate the down-regulation of aquaporin transcripts is a means to reduce the hydraulic conductivity of roots in situations when the osmotic gradient favors water efflux. However, post-translational modification including phosphorylation or removal of aquaporins from cell membranes may also be a component of the response. The objective of the study was to identify candidate proteins involved in post-translational modification of aquaporins by identifying proteins that physically interact with selected domains of aquaporin proteins.