Transcriptional dynamics and gene expression profiles along the foliar gradient in C3 and C4 grasses.

PROCHETTO S.; REINHEIMER R.

Congreso; RAFV Conference; 2021

C4 photosynthesis has allowed plants to adapt to high temperatures and solar radiation through better use of water and nitrogen. Despite the fact that only 3% of angiosperms use the C4 cycle, these species are among the most important crops on the planet (e.g. corn, sugar cane, sorghum) and cover about 25% of the Earth. In addition, species with C3-C4 intermediates photosynthesis are usually found near the C4 lineages. Indeed, current models indicate that the assembly of C4 photosynthesis was a gradual process that included the relocation of photorespiratory enzymes, and the establishment of intermediate photosynthesis subtypes. Interestingly, more than 1/3 of the C4 origins occurred within the grass family (Poaceae). In particular, the Otachyriinae subtribe (Paspaleae tribe) includes 35 American species from C3, C4 and intermediates taxa resulting in an interesting lineage to answer questions about the evolution and optimization of photosynthesis.To explore the molecular mechanisms responsible for the evolution of C4 photosynthesis, the transcriptional regulation of genes along leaf development was comparatively studied among Otachyriinae non-model species. For this, leaf transcriptomes were sequenced, de novo assembled and annotated. Then, transcriptional dynamics and gene expression along the foliar gradient were investigated. We found that genes associated with photorespiration and the C4 cycle are differentially expressed between C4 and C3 species, whereas their expression patterns are well preserved throughout leaf development.