ABSTRACT
Aquaporin (AQP) discovery allowed the understanding of a new notion about the dynamics of rapid and controlled water transport across membranes at the rate exceeding that of water diffusion. The small basic intrinsic proteins define the fourth plant AQP subgroup that was first uncovered from genome sequence analysis. Plant AQPs expressions are often triggered or suppressed by the symbiotic association of micro-organisms. A powerful tool in elucidating the AQP function is given by reverse genetics that can also reveal unexpected functions of water channel proteins, which benefit our understanding of sequence–structure and structure–function relationships in plants. The AQP family is a set of genes whose functions are intuitively perceived as important; much isolated information has been accumulated, yet their function is far from being understood in living plants, and we still have a long way to go to fully understand the significance of these proteins.
