ARS | Publication request: Arabidopsis Transcript and Metabolite Profiles: Ecotype-specific Acclimation to Open-air Elevated [CO2]

Submitted to: Plant Cell and Environment
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 4, 2008
Publication Date: N/A

Interpretive Summary: Carbon dioxide in the world¿s atmosphere is on the rise. In the last century it has risen 20% and this geologically unprecedented pace will continue resulting in an atmosphere in 2050 containing 50% more CO2 than it did in 1900. While this enrichment of the atmosphere CO2 portends certain hazards of which global warming is the most publicized, it also offers the potential to increase crop yield and water use efficiency. However, the genomic basis underlying the response of plants to global change is almost completely unexplored. This study takes advantage of the advance genomic tools that exist for Arabidopsis. The outcomes from this work identify suites of genes that are strong candidates in controlling and explaining important aspects of the response of plants to elements of global change.

Technical Abstract: A FACE (Free-Air CO2 Enrichment) experiment compared physiological parameters, and transcript and metabolite profiles of Arabidopsis thaliana ecotypes Col-0 and Cvi-0 at ambient (~375ppm) and elevated (~550ppm) CO2 concentration ([CO2]). Photosynthesis and photoassimilate pool sizes were enhanced in high [CO2] in an ecotype-specific manner. Short-term, growth at elevated [CO2] stimulated carbon gain irrespective of substantial down-regulation of plastid functions, and significantly altered expression of genes involved in nitrogen metabolism consistent with patterns observed under N-deficiency. The study confirmed well-known characteristics but the use of a time course, ecotypic genetic differences, metabolite analysis, and the focus on clusters of functional categories provided new aspects about plant acclimation to elevated [CO2]. Longer-term, Cvi-0 responded to elevated [CO2] by down-regulating functions favoring carbon accumulation and both ecotypes showed altered expression of genes for defense, redox control, transport, signaling and transcription, including chromatin-remodeling. Overall, carbon fixation with a smaller commitment of resources in elevated [CO2] appeared beneficial, while extra C was only partially utilized due to a disturbance of the C:N ratio. To different degrees, both ecotypes perceived elevated [CO2] as a metabolic perturbation that necessitated an increase in metabolic functions consuming or storing photoassimilate, with Cvi-0 emerging as more capable of acclimating. Elevated [CO2] in Arabidopsis favored adjustments in ROS homeostasis and signaling that appeared to define genotypic markers that determine the capacity to acclimate.