title: Whole gene family expression and drought stress regulation of aquaporins.
abstract: Since many aquaporins (AQPs) act as water channels, they are thought to play an important role in plant water relations. It is therefore of interest to study the expression patterns of AQP isoforms in order to further elucidate their involvement in plant water transport. We have monitored the expression patterns of all 35 Arabidopsis AQPs in leaves, roots and flowers by cDNA microarrays, specially designed for AQPs, and by quantitative real-time reverse transcriptase PCR (Q-RT-PCR). This showed that many AQPs are pre-dominantly expressed in either root or flower organs, whereas no AQP isoform seem to be leaf specific. Looking at the AQP subfamilies, most plasma membrane intrinsic proteins (PIPs) and some tonoplast intrinsic proteins (TIPs) have a high level of expression, while NOD26-like proteins (NIPs) are present at a much lower level. In addition, we show that PIP transcripts are generally down-regulated upon gradual drought stress in leaves, with the exception of AtPIP1;4 and AtPIP2;5, which are up-regulated. AtPIP2;6 and AtSIP1;1 are constitutively expressed and not significantly affected by the drought stress. The transcriptional down-regulation of PIP genes upon drought stress could also be observed on the protein level.
authors.affiliation: Department of Plant Biochemistry, Lund University, PO Box 124, SE-22100, Lund, Sweden. erik.alexandersson@plantbio.lu.se
authors.forename: Erik
authors.initials: E
authors.lastname: Alexandersson
authors.forename: Laure
authors.initials: L
authors.lastname: Fraysse
authors.forename: Sara
authors.initials: S
authors.lastname: Sjövall-Larsen
authors.forename: Sofia
authors.initials: S
authors.lastname: Gustavsson
authors.forename: Maria
authors.initials: M
authors.lastname: Fellert
authors.forename: Maria
authors.initials: M
authors.lastname: Karlsson
authors.forename: Urban
authors.initials: U
authors.lastname: Johanson
authors.forename: Per
authors.initials: P
authors.lastname: Kjellbom
mesh_terms: D020346:Aquaporins / Q000235:genetics* / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics*; D015153:Blotting, Western; D016000:Cluster Analysis; D004190:Disasters; D015536:Down-Regulation / Q000187:drug effects; D035264:Flowers / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D018515:Plant Leaves / Q000235:genetics; D018517:Plant Roots / Q000235:genetics; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D014867:Water / Q000494:pharmacology
chemical_list: D020346:Aquaporins; D020033:Protein Isoforms; D012333:RNA, Messenger; D014867:Water