Elevated CO2 influences the expression of floral-initiation genes in Arabidopsis thaliana

Atmospheric CO2 concentration ([CO2]) is rising on a global scale and is known to affect flowering time. Elevated [CO2] may be as influential as temperature in determining future changes in plant developmental timing, but little is known about the molecular mechanisms that control altered flowering times at elevated [CO2]. Using Arabidopsis thaliana, the expression patterns were compared of floral-initiation genes between a genotype that was selected for high fitness at elevated [CO2] and a nonselected control genotype. The selected genotype exhibits pronounced delays in flowering time when grown at elevated [CO2], whereas the control genotype is unaffected by elevated [CO2]. Thus, this comparison provides an evolutionarily relevant system for gaining insight into the responses of plants to future increases in [CO2]. Evidence is provided that elevated [CO2] influences the expression of floral-initiation genes. In addition, it is shown that delayed flowering at elevated [CO2] is associated with sustained expression of the floral repressor gene, FLOWERING LOCUS C (FLC), in an elevated CO2-adapted genotype. Understanding the mechanisms that account for changes in plant developmental timing at elevated [CO2] is critical for predicting the responses of plants to a high-CO2 world of the near future. (c) The Authors (2008). Journal compilation (c) New Phytologist (2008).