Rapid report Elevated CO 2 influences the expression of floral-initiation genes in Arabidopsis thaliana

Abstract

Summary • Atmospheric CO 2 concentration ([CO 2 ]) is rising on a global scale and is known to affect flowering time. Elevated [CO 2 ] 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 [CO 2 ]. • Using Arabidopsis thaliana, the expression patterns were compared of floralinitiation genes between a genotype that was selected for high fitness at elevated [CO 2 ] and a nonselected control genotype. The selected genotype exhibits pronounced delays in flowering time when grown at elevated [CO 2 ], whereas the control genotype is unaffected by elevated [CO 2 ]. Thus, this comparison provides an evolutionarily relevant system for gaining insight into the responses of plants to future increases in [CO 2 ]. • Evidence is provided that elevated [CO 2 ] influences the expression of floral-initiation genes. In addition, it is shown that delayed flowering at elevated [CO 2 ] is associated with sustained expression of the floral repressor gene, FLOWERING LOCUS C (FLC), in an elevated CO 2 -adapted genotype. • Understanding the mechanisms that account for changes in plant developmental timing at elevated [CO 2 ] is critical for predicting the responses of plants to a high-CO 2 world of the near future