ESKIMO1 is a key gene involved in water economy as well as cold acclimation and salt tolerance
- Equal contributors
1 Cell Biology Laboratory, IJPB, INRA-CIRAD, UR0501, Route de St Cyr, F-78026 Versailles, France
2 Physiology and Biotechnologies Laboratory, Faculty of Sciences, University of Lomé BP 1515 Lomé, Togo
3 Danmarks Tekniske Universitet, Institut for Vand og Miljøteknologi, Bygningstorvet, B115, DK-2800 KGS. Lyngby, Danmark
4 URGV, Plant Genomics Research Unit, INRA/CNRS, UMR11, 2 rue Gaston Crémieux CP5708, F-91057 Evry, France
5 CIRAD, Pôle de Protection des Plantes, Ligne Paradis, F-97410 St Pierre, France
6 Variability and Abiotic Stress Tolerance, Genetics and Plant Breeding Laboratory, IJPB, INRA, UR0254, Route de St Cyr, F-78026 Versailles, France
BMC Plant Biology 2008, 8:125 doi:10.1186/1471-2229-8-125Published: 7 December 2008
Drought is a major social and economic problem resulting in huge yield reduction in the field. Today's challenge is to develop plants with reduced water requirements and stable yields in fluctuating environmental conditions. Arabidopsis thaliana is an excellent model for identifying potential targets for plant breeding. Drought tolerance in the field was successfully conferred to crops by transferring genes from this model species. While involved in a plant genomics programme, which aims to identify new genes responsible for plant response to abiotic stress, we identified ESKIMO1 as a key gene involved in plant water economy as well as cold acclimation and salt tolerance.
All esk1 mutants were more tolerant to freezing, after acclimation, than their wild type counterpart. esk1 mutants also showed increased tolerance to mild water deficit for all traits measured. The mutant's improved tolerance to reduced water supply may be explained by its lower transpiration rate and better water use efficiency (WUE), which was assessed by carbon isotope discrimination and gas exchange measurements. esk1 alleles were also shown to be more tolerant to salt stress.
Transcriptomic analysis of one mutant line and its wild-type background was carried out. Under control watering conditions a number of genes were differentially expressed between the mutant and the wild type whereas under mild drought stress this list of genes was reduced. Among the genes that were differentially expressed between the wild type and mutant, two functional categories related to the response to stress or biotic and abiotic stimulus were over-represented. Under salt stress conditions, all gene functional categories were represented equally in both the mutant and wild type. Based on this transcriptome analysis we hypothesise that in control conditions the esk1 mutant behaves as if it was exposed to drought stress.
Overall our findings suggest that the ESKIMO1 gene plays a major role in plant response to water shortage and in whole plant water economy. Further experiments are being undertaken to elucidate the function of the ESKIMO1 protein and the way it modulates plant water uptake.