Periodic Report Summary - C4TRAN (C4 photosynthesis transcriptomics)
The objectives were to sample leaves of C3 and C4 congeneric pairs for gene expression and to identify patterns of gene expression associated with mesophyll and bundle sheath cells in C4 plants. This was done after developing a bioinformatic pipeline to allow this to be done after ribonucleic acid sequencing (RNAseq), but without genome sequence. We also implemented a new pipeline to allow unambiguous identification of homologous transcripts in different species. This has allowed to map alterations in gene expression as C4 is induced. We have defined genes that were previously not known to be associated with C4 photosynthesis, and also identified transcription factors that underlie these behaviours in gene expression. These transfactors are expressed in either mesophyll of bundle sheath cells. Furthermore, we find that the transcription factor homologues have been recruited in separate lineages of C4 plant indicating that parallel evolution of transfactors has generated this complex trait.