Natural variation reveals relationships between pre-stress carbohydrate nutritional status and subsequent responses to xenobiotic and oxidative stress in Arabidopsis thaliana.
BACKGROUND
Soluble sugars are involved in responses to stress, and act as signalling molecules that activate specific or hormone cross-talk transduction pathways. Thus, exogenous sucrose treatment efficiently induces tolerance to the herbicide atrazine in Arabidopsis thaliana plantlets, at least partially through large-scale modifications of expression of stress-related genes.


METHODS
Availability of sugars in planta for stress responses is likely to depend on complex dynamics of soluble sugar accumulation, sucrose-starch partition and organ allocation. The question of potential relationships between endogenous sugar levels and stress responses to atrazine treatment was investigated through analysis of natural genetic accessions of A. thaliana. Parallel quantitative and statistical analysis of biochemical parameters and of stress-sensitive physiological traits was carried out on a set of 11 accessions.


RESULTS
Important natural variation was found between accessions of A. thaliana in pre-stress shoot endogenous sugar levels and responses of plantlets to subsequent atrazine stress. Moreover, consistent trends and statistically significant correlations were detected between specific endogenous sugar parameters, such as the pre-stress end of day sucrose level in shoots, and physiological markers of atrazine tolerance.


CONCLUSIONS
These significant relationships between endogenous carbohydrate metabolism and stress response therefore point to an important integration of carbon nutritional status and induction of stress tolerance in plants. The specific correlation between pre-stress sucrose level and greater atrazine tolerance may reflect adaptive mechanisms that link sucrose accumulation, photosynthesis-related stress and sucrose induction of stress defences.
Ramel
Fanny
F
Université de Rennes 1, Centre National de la Recherche Scientifique, UMR 6553 ECOBIO, Campus de Beaulieu, bâtiment 14A, F-35042 Rennes Cedex, France.
Sulmon
Cécile
C
Gouesbet
Gwenola
G
Couée
Ivan
I
D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D001280:Atrazine / Q000494:pharmacology*; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D018525:Germination; D006540:Herbicides / Q000494:pharmacology*; D018384:Oxidative Stress; D010788:Photosynthesis; D025341:Principal Component Analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*
D006540:Herbicides; D017382:Reactive Oxygen Species; D013395:Sucrose; D001280:Atrazine