title: An expression analysis of a gene family encoding plasma membrane aquaporins in response to abiotic stresses in Arabidopsis thaliana.
abstract: Aquaporin belongs to a highly conserved group of membrane proteins called major intrinsic proteins that facilitate water transport across biological membranes. The genome of Arabidopsis encodes 35 aquaporin genes with 13 homologs in the plasma membrane intrinsic protein (PIP) subgroup. However, the function of each individual aquaporin isoform and the integrated function of plant aquaporins under various physiological conditions remain unclear. As a step toward understanding the aquaporin function in plants under various environmental stimuli, the expressions of a gene family encoding 13 PIPs in Arabidopsis thaliana under various abiotic stress conditions including drought, cold, and high salinity, or abscisic acid (ABA) treatment were investigated by a quantitative real-time reverse transcription-PCR analysis. Several PIP genes were predominantly expressed either in the roots or in the flowers. The expressions of both the highly expressed aquaporins including PIP1;1, PIP1;2, and PIP2;7 and the weakly expressed aquaporins such as PIP1;4, PIP2;1, PIP2;4, and PIP2;5 were modulated by external stimuli. The analyses of our data revealed that only the PIP2;5 was up-regulated by cold treatment, and most of the PIP genes were down-regulated by cold stress. Marked up- or down-regulation in PIP expression was observed by drought stress, whereas PIP genes were less-severely modulated by high salinity. The responsiveness of each aquaporin to ABA were different, implying that the regulation of aquaporin expression involves both ABA-dependent and ABA-independent signaling pathways. Together, our comprehensive expression profile of the 13 members of the PIP gene family provides novel basis to allocate the stress-related biological function to each PIP gene.
authors.affiliation: Division of Applied Plant Science and Agricultural Plant Stress Research Center, College of Agriculture and Life Sciences, Chonnam National University, 300 Yongbong-dong, Buk-gu, Gwangju 500-757, Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Dong Gu
authors.initials: DG
authors.lastname: Kim
authors.forename: Yeon Ok
authors.initials: YO
authors.lastname: Kim
authors.forename: Jin Sun
authors.initials: JS
authors.lastname: Kim
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D020346:Aquaporins / Q000235:genetics*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics; D003080:Cold Temperature; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008353:Mannitol / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics; D005810:Multigene Family / Q000235:genetics*; D010802:Phylogeny; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride / Q000494:pharmacology
chemical_list: D020346:Aquaporins; D029681:Arabidopsis Proteins; D008565:Membrane Proteins; D018749:RNA, Plant; D008353:Mannitol; D012965:Sodium Chloride; D000040:Abscisic Acid