Abstract

C4 photosynthesis has evolved independently over 60 times. In most cases it is established in a 2-celled system with bundle sheath cells and mesophyll cells in concentric circles around the veins. The genetic regulation of the typical C4 anatomy is not yet well understood. I am investigating the leaf development of four closely related C3 and C4 plants to analyse the differences in leaf development associated with C4 photosynthesis. Following a very detailed morphological study of developing leaves I show that young leaves of plants from both photosynthesis types contain gradients in leaf development from tip to base, with the tip possessing the same anatomy as mature leaves and the tissue at the base being undifferentiated. To understand the genetic regulation underlying the differences in C3 and C4 leaf anatomy, I have conducted an extensive RNA sequencing experiment that allows me to analyse which genes are expressed in which part of the developing leaf. The results of this are expected back within the next month. Mapping the results of this data back to my anatomical study will allow me to identify genes that are differentially expressed in the different parts of the leaf. This will help identify genes that are essential in regulating the establishment of the anatomical features that are specific for C4 species.