Molecular Characterization and Expression of Four Aquaporin Genes in During Drought Stress and Recovery.

Aquaporins comprise a large group of transmembrane proteins responsible for water transport, which is crucial for plant survival under stress conditions. Despite the vital role of aquaporins, nothing is known about this protein family in a commercially important horticultural plant, which is sensitive to drought stress. In the present study, attention is given to the molecular characterization of aquaporins in and their expression during drought stress and recovery. We identified four aquaporins: IwPIP1;4, IwPIP2;2, IwPIP2;7 and IwTIP4;1. All of them had conserved NPA motifs (Asparagine-Proline-Alanine), transmembrane helices (TMh), pore characteristics, stereochemical properties and tetrameric structure of holoprotein. Drought stress and recovery treatment affected the aquaporins expression in leaves, which was up- or downregulated depending on stress intensity. Expression of was the most affected of all analyzed aquaporins. At 15% and 5% soil moisture and recovery from 15% and 5% soil moisture, expression significantly decreased and increased, respectively. Aquaporins and had lower expression in comparison to , with moderate expression changes in response to drought and recovery, while expression was of significance only in recovered plants. Insight into the molecular structure of aquaporins expanded knowledge about plant aquaporins, while its expression during drought and recovery contributed to drought tolerance mechanisms and re-acclimation.