Gene expression and metabolite profiling of Populus euphratica growing in the Negev desert.
BACKGROUND
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.


RESULTS
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.


CONCLUSIONS
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.
Brosché
Mikael
M
Plant Biology, Department of Biological and Environmental Sciences, University of Helsinki, P,O, Box 65, Viikinkaari 1, FIN-00014 Helsinki, Finland. Mikael.brosche@helsinki.fi
Vinocur
Basia
B
Alatalo
Edward R
ER
Lamminmäki
Airi
A
Teichmann
Thomas
T
Ottow
Eric A
EA
Djilianov
Dimitar
D
Afif
Dany
D
Bogeat-Triboulot
Marie-Béatrice
MB
Altman
Arie
A
Polle
Andrea
A
Dreyer
Erwin
E
Rudd
Stephen
S
Paulin
Lars
L
Auvinen
Petri
P
Kangasjärvi
Jaakko
J
D003889:Desert Climate; D004190:Disasters; D020224:Expressed Sequence Tags; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant / Q000235:genetics; D018745:Genome, Plant / Q000235:genetics; D007557:Israel; D020411:Oligonucleotide Array Sequence Analysis; D018515:Plant Leaves / Q000737:chemistry; D032107:Populus / Q000145:classification / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012965:Sodium Chloride; D014197:Trees / Q000254:growth & development / Q000378:metabolism
D012333:RNA, Messenger; D012965:Sodium Chloride