부산대학교 도서관

C4photosynthesis acts as a carbon concentrating mechanism that leads to large increases in photosynthetic efficiency. The C4pathway is found in more than 60 plant lineages1but the molecular enablers of this evolution are poorly understood. In particular, it is unclear how non-photosynthetic proteins in the ancestral C3system have repeatedly become strongly expressed and integrated into photosynthesis gene regulatory networks in C4leaves. Here, we provide clear evidence that in C3leaves, genes encoding key enzymes of the C4pathway are already co-regulated with photosynthesis genes and are controlled by both light and chloroplast-to-nucleus signalling. In C4leaves this regulation becomes increasingly dependent on the chloroplast. We propose that regulation of C4cycle genes by light and the chloroplast in the ancestral C3state has facilitated the repeated evolution of the complex and convergent C4trait.