title: Identification and characterization of two plasma membrane aquaporins in durum wheat (Triticum turgidum L. subsp. durum) and their role in abiotic stress tolerance.
abstract: Plant plasma membrane intrinsic proteins (PIP) cluster in two phylogenetic groups, PIP1 and PIP2 that have different water channel activities when expressed in Xenopus oocytes. PIP2s induce a marked increase of the membrane osmotic water-permeability coefficient (P(f)), whereas PIP1s are generally inactive. Here we report the cloning of two durum wheat (Triticum turgidum L. subsp. durum) cDNAs encoding TdPIP1;1 and TdPIP2;1 belonging to the PIP1 and PIP2 subfamilies, respectively. Contrary to TdPIP1;1, expression of TdPIP2;1 in Xenopus oocytes resulted in an increase in P(f) compared to water-injected oocytes. Co-expression of the non-functional TdPIP1;1 and the functional TdPIP2;1 lead to a significant increase in P(f) compared with oocytes expressing TdPIP2;1 alone. A truncated form of TdPIP2;1, tdpip2;1, missing the first two transmembrane domains, had no water channel activity. Nonetheless, its co-expression with the functional TdPIP2;1 partially inhibits the P(f) and disrupt the activities of plant aquaporins. In contrast to the approach developed in Xenopus oocytes, phenotypic analyses of transgenic tobacco plants expressing TdPIP1;1 or TdPIP2;1 generated a tolerance phenotype towards osmotic and salinity stress. TdPIP1;1 and TdPIP2;1 are differentially regulated in roots and leaves in the salt-tolerant wheat variety when challenged with salt stress and abscisic acid. Confocal microscopy analysis of tobacco roots expressing TdPIP1;1 and TdPIP2;1 fused to the green fluorescent protein showed that the proteins were localized at the plasma membrane.
authors: Plant Protection and Improvement Laboratory, Centre of Biotechnology of Sfax, University of Sfax, Route Sidi Mansour Km 6, BP 1177, 3018 Sfax, Tunisia.
authors: Malika
authors: M
authors: Ayadi
authors: Damien
authors: D
authors: Cavez
authors: Nabil
authors: N
authors: Miled
authors: François
authors: F
authors: Chaumont
authors: Khaled
authors: K
authors: Masmoudi
mesh_terms: D000818:Animals; D020346:Aquaporins / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013312:Stress, Physiological / Q000502:physiology*; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000378:metabolism; D014981:Xenopus
chemical_list: D020346:Aquaporins; D010940:Plant Proteins; D011994:Recombinant Proteins; D014867:Water