The Coordination and Jumps along C4Photosynthesis Evolution in the GenusFlaveria

Background C 4 photosynthesis is a remarkable complex trait, elucidations of the evolutionary trajectory of C 4 photosynthesis from its ancestral C 3 pathway can help us to better understand the generic principles of complex trait evolution and guide engineering of C 3 crops for higher yields. We used the genus Flaveria that contains C 3 , C 3 -C 4 , C 4 -like and C 4 species as a system to study the evolution of C 4 photosynthesis. Results We mapped transcript abundance, protein sequence, and morphological features to the phylogenetic tree of the genus Flaveria , and calculated the evolutionary correlation of different features. Besides, we predicted the relative changes of ancestral nodes of those features to illustrate the key stages during the evolution of C 4 photosynthesis. Gene expression and protein sequence showed consistent modification pattern along the phylogenetic tree. High correlation coefficients ranging from 0.46 to 0.9 among gene expression, protein sequence and morphology were observed, and the greatest modification of those different features consistently occurred at the transition between C 3 -C 4 species and C 4 -like species. Conclusions Our data shows highly coordinated changes in gene expression, protein sequence and morphological features. Besides, our results support an obviously evolutionary jump during the evolution of C 4 metabolism.