Gene expression and metabolite profiling of Populus euphratica growing in the Negev desert
1 Plant Biology, Department of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, Viikinkaari 1, FIN-00014 Helsinki, Finland
2 The Robert H Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agricultural, Food and Environmental Quality Sciences, The Hebrew University of Jerusalem, Herzl Street, Rehovot 76100, Israel
3 Institute of Biotechnology, University of Helsinki, P.O. Box 56, Viikinkaari 4, FIN-00014 Helsinki, Finland
4 Institut für Forstbotanik, Georg-August-Universität Göttingen, Büsgenweg 2, 37077 Göttingen, Germany
5 AgroBioInstitute, 8 Dragan Tzankov Boulevard, 1164 Sofia, Bulgaria
6 UMR INRA-UHP Ecologie et Ecophysiologie Forestières, Faculté des Sciences, F-54506 Vandoeuvre, France
7 UMR INRA-UHP Ecologie et Ecophysiologie Forestières, IFR 110 Génomique, Ecophysiologie et Ecologie Fonctionnelle, INRA Nancy, Route d'Amance, F-54280 Champenoux, France
8 Turku Centre for Biotechnology, BioCity, Tykistökatu 6, FIN-20521 Turku, Finland
Genome Biology 2005, 6:R101 doi:10.1186/gb-2005-6-12-r101Published: 2 December 2005
Plants growing in their natural habitat represent a valuable resource for elucidating mechanisms of acclimation to environmental constraints. Populus euphratica is a salt-tolerant tree species growing in saline semi-arid areas. To identify genes involved in abiotic stress responses under natural conditions we constructed several normalized and subtracted cDNA libraries from control, stress-exposed and desert-grown P. euphratica trees. In addition, we identified several metabolites in desert-grown P. euphratica trees.
About 14,000 expressed sequence tag (EST) sequences were obtained with a good representation of genes putatively involved in resistance and tolerance to salt and other abiotic stresses. A P. euphratica DNA microarray with a uni-gene set of ESTs representing approximately 6,340 different genes was constructed. The microarray was used to study gene expression in adult P. euphratica trees growing in the desert canyon of Ein Avdat in Israel. In parallel, 22 selected metabolites were profiled in the same trees.
Of the obtained ESTs, 98% were found in the sequenced P. trichocarpa genome and 74% in other Populus EST collections. This implies that the P. euphratica genome does not contain different genes per se, but that regulation of gene expression might be different and that P. euphratica expresses a different set of genes that contribute to adaptation to saline growth conditions. Also, all of the five measured amino acids show increased levels in trees growing in the more saline soil.