© 2004 Heron Publishing—Victoria, Canada
Transcript identification and profiling during salt stress and recovery of Populus euphratica
Ruisheng Gu (1, 2), Sandra Fonseca (1), László G. Puskás (3), László Hackler, Jr. (3), Ágnes Zvara (3), Dénes Dudits (4) and Maria S. Pais (1)
1. Laboratory of Plant Biotechnology, ICAT, Campo Grande, 1749-016, Lisbon, Portugal / 2. Corresponding author (rsgu@icat.fc.ul.pt or rsgu@hotvoice.com) / 3. DNA-Chip Laboratory, Biological Research Center, Hungarian Academy of Sciences, Szeged, P.O. Box 521, H-6701, Hungary / 4. Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, Szeged, P.O. Box 521, H-6701, Hungary / Received February 20, 2003; accepted July 26, 2003; published online January 2, 2004
Summary
Populus euphratica Oli. is a salt-tolerant species that can cope with up to 450 mM NaCl under hydroponic conditions and can tolerate high accumulations
of Na+ and Cl– in roots and leaves when grown in 300 mM NaCl. Transcript responses to salt stress and recovery were monitored by microarray
hybridization of 315 cDNAs preselected by suppression subtractive hybridization. Transcripts of a heat-shock protein and a
hydroxyproline-rich glycoprotein accumulated 1.5 and 3 h, respectively, after adding 300 mM NaCl to the culture medium. Transcripts
significantly up-regulated by salt stress included ionic and osmotic homeostasis elements such as magnesium transporter-like
protein, syntaxin-like protein, seed imbibition protein and plasma membrane intrinsic protein; metabolism regulators like
cytochrome P450, zinc finger protein, cleavage factor and aminotransferase; and the photosynthesis-activating enzyme Rubisco
activase and photorespiration-related glycolate oxidase. Several photosynthesis-related transcripts were down-regulated in
response to 72 h of salt stress but were up-regulated after long-term recovery (48 h). Sucrose synthase, ABC transporter,
calmodulin, Pop3 peptide and aquaporin appeared to be actively involved in the process of plant recovery from salt stress.
Several transcripts encoding proteins of unknown function were regulated by salt stress. Selected transcripts exhibiting altered
transcript profiles in response to salt stress were also analyzed by real-time quantitative PCR. Transcript analysis during
salt stress and recovery of this woody species revealed several genes and corresponding proteins deserving special attention
in future studies of salt tolerance in woody species.
Keywords:
ionic intensity, ionic mapping, microarray, real-time PCR, suppression subtractive hybridization, transcript regulation.
