I did my Bachelor of Biotechnology at the University of Newcastle with honours under the guidance of Professor Chris Grof. Following this, I moved to Canberra to do my PhD with Professor Bob Furbank at The Australian National University which I finished in 2020 working on SWEETs in S. viridis. As a PhD student I was a part of the ARC Centre of Excellence for Translational Photosynthesis which enabled me to learn a variety of molecular biology skills. After the completion of my PhD I moved to Western Sydney University to take up a Postdoctoral position with Professor Oula Ghannoum working sugar sensing in C4 grasses under a ARC Discovery Project in collaboration with Bob Furbank and Dr Matthew Paul at Rothamsted Research.
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The SWEET path and sugar sensing of C4 photosynthetic grasses
L. CHEN1,2, U. BENNING, R. T. FURBANK<sup>2</sup>, O. GHANNOUM<sup>1</sup>
1Hawkesbury Institute for the Environment, Western Sydney University, Hawkesbury Campus, New South Wales 2753, Australia
2ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
Despite a large proportion of the world’s crops being C4 grasses such as maize and millets such as Setaria, it is unclear how sugars are partitioned and sensed in the leaf. C3 species perform photosynthesis and carbohydrate synthesis in one cell (mesophyll) whereas in C4 species these reactions occur in a two-cell system (mesophyll and bundle sheath). Here Sugars Will Eventually be Exported Transporters (SWEET) were found on the bundle sheath and the phloem cells of the C4 grass Setaria viridis using immunolocalisation. Using Xenopus laevis oocytes as a heterologous system demonstrated they function as high-capacity transporters of both glucose and sucrose, the dominant sugars in most C4 grasses. This has established a role for these transporters within this C4 model grass. Subsequent work has now expanded into how these sugars are sensed in the C4 photosynthetic cells of C4 grasses. RNAseq data from the mesophyll and bundle cells of C4 grasses examined the expression profiles of sugar sensor genes. SnRK1β1 and TPS1 were preferentially expressed in the mesophyll and bundle sheath cells, respectively, with more changes observed within each species. Collectively, these studies expand our knowledge of the sugar transport and sensing pathways of C4 grasses.