Abstract
The responses of Populus euphratica Oliv. plants to soil water deficit were assessed by analyzing gene expression, protein profiles, and several plant performance criteria to understand the acclimation of plants to soil water deficit. Young, vegetatively propagated plants originating from an arid, saline field site were submitted to a gradually increasing water deficit for 4 weeks in a greenhouse and were allowed to recover for 10 d after full reirrigation. Time-dependent changes and intensity of the perturbations induced in shoot and root growth, xylem anatomy, gas exchange, and water status were recorded. The expression profiles of approximately 6,340 genes and of proteins and metabolites (pigments, soluble carbohydrates, and oxidative compounds) were also recorded in mature leaves and in roots (gene expression only) at four stress levels and after recovery. Drought successively induced shoot growth cessation, stomatal closure, moderate increases in oxidative stress-related compounds, loss of CO2 assimilation, and root growth reduction. These effects were almost fully reversible, indicating that acclimation was dominant over injury. The physiological responses were paralleled by fully reversible transcriptional changes, including only 1.5% of the genes on the array. Protein profiles displayed greater changes than transcript levels. Among the identified proteins for which expressed sequence tags were present on the array, no correlation was found between transcript and protein abundance. Acclimation to water deficit involves the regulation of different networks of genes in roots and shoots. Such diverse requirements for protecting and maintaining the function of different plant organs may render plant engineering or breeding toward improved drought tolerance more complex than previously anticipated.
Highlights
The responses of Populus euphratica Oliv. plants to soil water deficit were assessed by analyzing gene expression, protein profiles, and several plant performance criteria to understand the acclimation of plants to soil water deficit
Water Stress in Poplar: Gene Expression and Ecophysiology reduction of cell expansion (Boyer et al, 1985; Cosgrove, 1987) and, at the molecular scale, identification of key genes involved in drought-induced cell wall stiffening (Cosgrove, 2000; Sharp et al, 2004), will contribute to the understanding of the loss of productivity recorded at the organism and ecosystem scales
Decline of stem diameter increment was the first detected effect of soil water depletion (Fig. 1A). It started as soon as soil-REW dropped below 60%, while stem elongation declined at later stages (Fig. 2A; Supplemental Fig. S2)
Summary
The responses of Populus euphratica Oliv. plants to soil water deficit were assessed by analyzing gene expression, protein profiles, and several plant performance criteria to understand the acclimation of plants to soil water deficit. Water Stress in Poplar: Gene Expression and Ecophysiology reduction of cell expansion (Boyer et al, 1985; Cosgrove, 1987) and, at the molecular scale, identification of key genes involved in drought-induced cell wall stiffening (Cosgrove, 2000; Sharp et al, 2004), will contribute to the understanding of the loss of productivity recorded at the organism and ecosystem scales. They may help to select genotypes with an improved ability to cope with drought in the future (Vinocur and Altman, 2005; Polle et al, 2006). The changes in transcript and protein profiles underlying the gradual steps of such acclimation processes have received little attention to date
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
