Mortimer Plant Cell Wall Biosynthesis and Function
Jenny started working on cell walls as a postdoc with Prof. Paul Dupree at the University of Cambridge, and it sparked a lifelong fascination with complex glycosylation. Our lab carries out polysaccharide structural analysis and quantification using an array of methods including PACE, HPAEC-PAD, mass spec, NMR (solid and solution state) and MST.
Our research has included the discovery of xylan glucuronosyl transferases (Mortimer et al. 2010, PNAS; Mortimer et al. 2015, Plant J), and with that the engineering of the first plants with unbranched xylan. We then applied multi-dimensional solid-state NMR to plant secondary cell walls, leading to the discovery that dicot xylan takes different forms in the cell wall, which in turn drives function (Simmons#, Mortimer# et al. 2016, Nat. Comms). Subsequently, we have shown that sorghum has different patterning, information critical to tailor biomass deconstruction (Gao et al. 2020, Nat Comms). Other highlights include characterising mannan, pectin and nucleotide sugar transporter genes (e.g. Mortimer et al. 2013, Plant J; Gao et al. 2023, Plant J; Sechet et al. 2018, Plant J). Most recently, we have developed a new method for studying lethal glycosyltransferases (GTs), and characterised the first eukaryotic CMP-Kdo transferase which functions in RG-II biosynthesis (Zhang et al. 2024, Plant Phys.). We are now using this tool to discover the function of additional uncharacterised GTs. We've also recently started exploring the role of metabolite glycosylation in wine smoke taint in collaboration with the Wilkinson group, and we are developing new lignin analytics using TDA-MS.
Sphingolipid Glycosylation and Function
Glycosyl Inositol Phospho Ceramides (GIPCs) are heavily glycosylated sphingolipids found primarily in the outer leaflet of the plant membrane. We discovered the first GIPC glycosylation gene (admittedly, Jenny spent a long time thinking it was involved in mannan biosynthesis; Mortimer et al. 2013, Plant Cell), and subsequently identified the majority of the glycosylation pathway in Arabidopsis and rice (Fang et al. 2016, Plant Cell; Ishikawa et al. 2018, Plant Physiology; Jing et al. 2021, Plant Direct). In collaboration, we also characterised some GIPC function (Lenarcic et al. 2017, Science; Yan et al. 2019, Nature Plants; Mortimer & Scheller, 2020, TiPS) as well as exploring the function of related lipids (e.g. Sha et al. 2023, Nature).
Interactions Between Plant Cell Walls and the Microbiome
The plant cell wall is the interface between the plant cell and the environment. As part of m-CAFEs, we use fabricated ecosystems and synthetic communities to explore these mechanisms (Priya et al. bioRxiv). We have shown these are reproducible systems for studying syncom–plant interactions (Lin et al. 2023, Phytobiomes) and that small molecule exudates are key drivers of these interactions (Hu et al. bioRxiv). We have also been involved in work showing that the synergistic nature of microbiomes is key to rapid cell wall deconstruction (e.g. Lankiewicz et al. 2023, Nature Micro; Tom et al. 2022, Microbiome; Rogowski et al. 2015, Nature Comms).
Technologies for Improving Plant Transformation and Synthetic Biology
Transformation is a huge bottleneck for the application of new technologies to plants, and our work has included testing the potential for nanotechnology in plant transformation (e.g. Demirer et al. 2021, Nature Nanotech; Vejlupkova et al. 2020, Nature Plants), and developing new tools for improving and implementing gene editing (e.g. Liang et al. 2019, Biotech Biofuels; Liang et al. 2017, ACS Synbio), including in major crops (e.g. herbicide tolerant wheat) and new (Space) crops (e.g. duckweed — see below). We're also very conscious of the ethics and regulatory issues surrounding these questions, and are fortunate to collaborate with legal and social science experts who are researching these issues.
Application of Plant Engineering to Biomanufacturing
As part of JBEI, our group has built on our fundamental cell wall discoveries to engineer biomass for improved performance (e.g. Li et al. 2018, BMC Biotech; Eudes et al. 2023, FiPS). We have also collaborated with civil and chemical engineers to apply life cycle assessment (LCA) and technoeconomic assessment (TEA) to in planta production (e.g. Baral et al. 2019, ACS Sus Chem Eng; Baral et al. 2020, ACS Sus Chem Eng; Yang et al. 2020, PNAS). As part of P4S, we are focused on the idea of using indoor agriculture to drive plant-based biomanufacturing.
Space Plants and Indoor Agriculture
More recently, we've been exploring how we can apply synthetic biology to redesign plants for enclosed environments here on Earth, but also to support long-term human habitation in Space (Mortimer & Gilliham 2022, and Morgan et al. 2024, Current Opin Biotech; Morgan et al. 2024). We were part of the team awarded the ARC CoE in Plants for Space (P4S), which launched (!) in 2024. We have some exciting projects in the lab collaborating with Space industry (e.g. Axiom, Space Lab Technology), government (e.g. NASA, ASA, UKSPA, DLR), and the vertical farming industry (e.g. Vertical Future). We've also developed the Australian Collection of Duckweed Clones. Lots to come here…
Developing Feedstocks for the Emerging Bioeconomy
Building on our fundamental work in understanding cell wall synthesis and structure, and engineering plants with cell walls optimised for deconstruction, we have worked to test them in the field and in deconstruction processes. We're also testing whether duckweed can be grown on anaerobic digestate as part of sustainable agriculture systems using dairy and swine waste.