Insights into C 4 metabolism from comparative deep sequencing

Abstract

C4 photosynthesis suppresses the oxygenation activity of Ribulose Bisphosphate Carboxylase Oxygenase and so limits photorespiration. Although highly complex, it is estimated to have evolved in 66 plant lineages, with the vast majority lacking sequenced genomes. Transcriptomics has recently initiated assessments of the degree to which transcript abundance differs between C3 and C4 leaves, identified novel components of C4 metabolism, and also led to mathematical models explaining the repeated evolution of this complex phenotype. Evidence is accumulating that this complex and convergent phenotype is partly underpinned by parallel evolution of structural genes, but also regulatory elements in both cis and trans. Furthermore, it appears that initial events associated with acquisition of C4 traits likely represent evolutionary exaptations related to non-photosynthetic processes.

Update: Improving the Efficiency of Photosynthetic Carbon Reactions

“…Efforts to engineer C 4 photosynthesis into C 3 plant species were hampered by an incomplete list of genes and gene functions required to support the trait. The prospects massively improved with the advent of nextgeneration sequencing technologies, which enabled the comparison of gene expression patterns between related C 3 , C 3 -C 4 intermediate, and C 4 species, thereby generating lists of candidate genes involved in setting up C 4 leaf anatomy and completing the inventory of genes encoding the metabolic enzymes and solute transporters required to run C 4 biochemistry (Wang et al, 2013(Wang et al, , 2016Fouracre et al, 2014;Burgess and Hibberd, 2015;Weber, 2015). Also, computational modeling of the evolutionary trajectory from C 3 to C 4 photosynthesis provided guidance for the implementation of the C 4 trait in C 3 backgrounds (Heckmann et al, 2013;Williams et al, 2013;Li et al, 2017).…”

Comparative cell-specific transcriptomics reveals differentiation of C4photosynthesis pathways in switchgrass and other C4lineages

“…C 4 photosynthesis is thought to have first arisen ~30 million years ago and is found in >66 independent lineages of monocotyledons and dicotyledons ( Aubry et al , 2014 ; Burgess and Hibberd, 2015 ) ( Fig. 1 ).…”

Exploring natural variation of photosynthesis in a site-specific manner: evolution, progress, and prospects

“…Also, new evidence for gene regulation of C 4 biochemistry was revealed by a systems biology approach utilizing transcriptomic data. These transcriptomic data also provided a platform for the computational modeling that facilitated the creation of a metabolic map of the C 4 pathway (Burgess and Hibberd 2015). The first molecular evidence of C 4 Kranz anatomy is one such finding that can be further developed for engineering the C 4 pathway into C 3 plants (John et al 2014;Li et al 2015).…”