Evolution of the C4 Photosynthetic Pathway
My research interests include the cell and molecular biology, molecular genetics and evolution of photosynthetic pathways. Plants require sunlight, water and atmospheric CO2 to carry out photosynthesis, one of the most fundamental processes on earth. Depending on its biochemistry, a plant is described as a C3, a C4 or a Crassulacean Acid Metabolism (CAM) plant. C4 and CAM species have evolved from C3 plants and this process has occurred multiple times in different families of plants. However, the molecular events underlying the evolution of C4 and CAM plants from their C3 ancestors have not been elucidated. We use species from the genus Flaveria that demonstrate C3, C4 or C3-C4 intermediate-type photosynthesis to examine the anatomical and molecular changes that have occurred during the evolution of C4 plants. We have focused our work on the enzyme carbonic anhydrase, which although involved in both the C3 and C4 photosynthetic pathways, shows differences in intracellular location and patterns of expression in C3 and C4 plants. We have identified gene sequences that appear responsible for these differences and we are currently examining their functional significance as well as the cellular expression patterns of the enzymes in C3 and C4 Flaveria species.
More recently, we have begun to examine the molecular evolution of the C4 pathway in the Australian native grass subtribe, the Neurachninae. This group is the only known grass lineage with distinct, closely related C3, C3-C4 and C4 species, and these species are found only in Australia.
My research group uses a combination of cell and molecular biology and genetics techniques to investigate the above research areas. We look at the products of gene expression using in situ localisation methods that involve microscopy with antibodies and nucleic acid probes. We investigate the genes and the sequences controlling when, where and how they are active using recombinant DNA technology; real-time PCR; RNA-Seq; and immunoblotting techniques. We use transgenic technologies to examine the functions of gene products and to investigate the effects on plant productivity when a plant makes more or less of a given protein than wild type plants.
My group has strong, productive collaborations with other UWA research groups and international researchers in North America and Germany.
Students interested in the above research areas are encouraged to approach Dr Ludwig about potential Honours, Master and PhD projects.
Prof Peter Westhoff, Heinrich-Heine University, Germany
Prof Andreas Weber, Heinrich-Heine University, Germany
Dr John Lunn, Max Planck Institute for Plant Molecular Physiology, Germany
Prof Mark Stitt, Max Planck Institute for Plant Molecular Physiology, Germany
Prof Rowan Sage, University of Toronto, Canada
Assoc/Prof Tammy Sage, University of Toronto, Canada
Dr Terry Macfarlane, Western Australian Herbarium, Department of Biodiversity, Conservation and Attractions
Dr Martha Ludwig completed a Bachelor of Arts, majoring in Biological Sciences, at Smith College in Northampton, Massachusetts. She moved to McGill University in Montreal to do post-graduate work that examined how chloroplasts evolved from eukaryotic symbionts in Chlorarachnion and the cryptomonad algae. In her first post-doctoral position, she looked at cell surface antigens in various groups of algae at The University of Melbourne. Dr Ludwig then undertook post-doctoral research studying CO2 concentrating mechanisms, including the evolution of the C4 photosynthetic pathway as an ARC Post-doctoral Research Fellow at The Queensland University of Technology and subsequently added cyanobacterial CO2 concentrating mechanisms at the Research School of Biological Sciences at The Australian National University. She was a lecturer at The Australian National University and Macquarie University, before moving to The University of Western Australia in 2003. Her research focuses on the molecular evolution, biochemistry and genetics of C4 photosynthesis in mono- and dicotyledonous plants.
Australian Research Post-doctoral Fellow, School of Life Science, Queensland University of Technology
Post-doctoral Fellow, Research School of Biological Sciences, Australian National University
Lecturer, Division of Biochemistry and Molecular Biology, Australian National University
Lecturer, Department of Biological Sciences, Macquarie University
Currently: Molecular Biology (BIOC3001), Cellular Biochemistry (BIOC3005), Evolution and Development (GENE3350), Genomics (GENE3370)
Previously: Molecular Biology of the Cell (SCIE1106), Biochemistry and Molecular Biology of the Cell (BIOC2001), Biochemical Regulation of Cell Function (BIOC2002), Molecular Biology (BIOC3001), Cellular Biochemistry (BIOC3005), Principles of Inhertitance (GENE2250), Evolution and Development (GENE3350), Genomics (GENE3370)
Roles and responsibilities
Head of School, Molecular Sciences (continuing)
Associate Dean, International, Faculty of Science (2018-2019)
Associate Head of School of Chemistry and Biochemistry/Molecular Sciences, Education (2017-2019)
Master of Biotechnology specialisation coordinator for Biochemistry and Molecular Biology, Genetics and Genomics (2014-2019)
Master of Biomedical Science specialisation coordinator for Biochemistry and Molecular Biology (2014-2019)
The molecular evolution of C4 photosynthesis.
Molecular Biology and Genetics
Isolation of DNA and RNA; RNA-Seq; construction and screening of cDNA libraries; PCR; RT-qPCR; automated DNA sequencing; RNA-Seq, expression of plant genes in heterologous expression systems; transgenics
Recombinant protein expression and purification; SDS-PAGE; immunoblotting
Light, fluorescence and confocal microscopy; transmission electron microscopy; in situ localisation of macromolecules
Research expertise keywords
- Carbon concentrating mechanisms
- Plant cell and molecular biology
- Molecular evolution of C4 and CAM photosynthetic pathways