Exploring the genetic diversity of Brazilian Cleomaceae species to understand the evolution of photosynthesis

Abstract:

The Cleomaceae family is closely related to the Brassicaceae and includes species with diverse carbon concentrating mechanisms (CCMs). As such, it offers a valuable resource for studying the evolution of CCMs. However, there is still limited genetic information available for Cleomaceae species, which limit their use in research applications. To address a portion of this issue, we examined 22 Cleomaceae accessions collected from different regions of Brazil and categorized them into separate groups based on not only molecular markers, but also other physiological characteristics. Although most of the species displayed the mai n characteristics of C3 photosynthesis, we observed variations in nuclear genome size, biochemical, physiological, and anatomical parameters both within and between species. In addition, the C3 like accessions displayed noteworthy anatomical adaptations, such as increase in venation density and bundle sheath cell size compared to their C4 accession. These adaptations may have provided a foundation for the evolution of C4 photosynthesis within these lineages. Recently, we were able to generate interspecific hybrids lines among C3 and C4 Cleomaceae species. Preliminary analyzes of these hybrids indicated the existence of segregation of parameters related to photosynthesis, such as the CO2 compensation point and anatomical traits. I will present our latest findings and demonstrate the potential of the Brazilian Cleomaceae species to provide novel insights into photosynthesis evolution.