Research Interests
I am interested in the fundamental question of how the coordination of cell proliferation, cell growth and cell differentiation results in the development of plant organs of specific size, shape and function. I am particularly interested in the gene regulatory networks that direct and coordinate these post-embryonic organogenesis processes and hence generate the enormous diversity we find among plant organs.
During my PhD in the group of Prof. Robert Sablowski at the John Innes Centre in Norwich UK , I explored how meristematic stem cells transition to organ primordium cells during floral organogenesis and how this process is regulated by the transcriptional regulator JAGGED in Arabidopsis. I showed that changes in the coordination between cell division and growth at the founder cell stage have profound effects on the size, shape and function of floral organs (Schiessl et al. 2012; Sauret-Güeto et al. 2013; Schiessl et al. 2014).
Recently, I have been more and more intrigued by the fact that plant colonisers such as bacteria, nematodes and insects can recruit these plant endogenous organogenesis pathways for their own benefit and induce and direct the development of costume-built organs that are commonly referred as plant galls.
A very specific case of coloniser-induced organs are symbiotic root nodules that develop on the roots of legumes in response to the infection by beneficial nitrogen-fixing rhizobial bacteria which provide the plant with ammonia in exchange for carbon. These symbiotic nodules are very distinct from lateral roots in morphology and function. In particular, nodules are comprised of cells that can accommodate nitrogen-fixing rhizobial bacteria intracellularly – endo-symbiotically and that provide favourable conditions for the biological nitrogen fixation process.
Symbiotic root nodule in the model legumes Medicago truncatula induced in response to successful recognition and infection with the beneficial nitrogen-fixing rhizobium bacteria Sinorhizobium meliloti (stained in blue).
The aim of my research in the group of Prof. Giles Oldroyd here at the SLCU is to discover and understand the regulatory pathways that are recruited to direct the growth and development of the symbiotic root nodule. We have recently discovered that the initiation of lateral roots and symbiotic nodules converges at a common developmental pathway (Schiessl et al. 2019). These findings put further emphasis on the hypothesis that additional nodule-specific regulators are required to determine nodule organ identity. For this reason, I am currently focussing my investigations on the regulatory pathways that promote nodule growth and the differentiation of the endosymbiotic host cells, a process that is tightly linked with the successful colonisation by the bacteria.
A substantial overlap exists in the developmental programmes plants use for lateral roots and nitrogen-fixing nodules: We found that plants that form nitrogen-fixing nodules have adopted the same programme used to grow lateral roots, which evolved many millions of years before nodulation evolved, instead of evolving a completely new programme. This is really exciting as it means that a substantial part of the machinery needed to form nodules is already present in non-nodulating plants.
Media Features
Growing excitement about self‑fertilising crops | The Times
Publications
Feng, J, Lee T, Schiessl K, and Oldroyd G E D: Processing of NODULE INCEPTION controls transition to nitrogen fixation in root nodules. Science 2021 (DOI: 10.1126/science.abg2804).
D'Ario M, Tavares R, Schiessl K, Desvoyes B, Gutierrez C., Howard M and Sablowski R. Cell size controlled in plants using DNA content as an internal scale. Science 2021 ( DOI: 10.1126/science.abb4348).
Yang W, Cortijo S, Korsbo N, Roszak P, Schiessl K, Gurzadyan A, Wightman R, Jönsson H, Meyerowitz E. Molecular mechanism of cytokinin-activated cell division in Arabidopsis. Science 2021 (DOI: 10.1126/science.abe2305).
Schiessl K, LilleyJ L S, LeeT, TamvakisI, KohlenW, BaileyP C, ThomasA, LuptakJ, RamakrishnanK, CarpenterM D, MysoreK S, WenJ, AhnertS, GrieneisenV A and Oldroyd G E D: NODULE INCEPTION recruits the lateral root developmental program for symbiotic nodule organogenesis in Medicago truncatula. Current Biology 2019 (DOI: 10.1016/j.cub.2019.09.005).
: MtNODULE ROOT1 and MtNODULE ROOT2 Are Essential for Indeterminate Nodule Identity. Plant Physiology 2018 (DOI: 10.1104/pp.18.00610).
Mislata A, Bencivenga S, Bush M, Schiessl K, Boden S and Sablowski R: DELLA genes restrict inflorescence meristem function independently of plant height. Nature Plants 2017 (DOI: 10.1038/s41477-017-0003-y).
Mislata A, Schiessl K, Sablowski R: Active control of cell size generates spatial detail during plant organogenesis. Current Biology 2015 (DOI:10.1016/j.cub.2015.10.008).
Schiessl K, Muino J M, Sablowski R: Arabidopsis JAGGED links floral organ patterning to tissue growth by repressing Kip-related cell cycle inhibitors. PNAS 2014 (DOI:10.1073/pnas.1320457111).
Sauret-Güeto S, Schiessl K, Bangham A, Sablowski R, Coen E: JAGGED Controls Arabidopsis Petal Growth and Shape by Interacting with a Divergent Polarity Field. PLOS Biology 2013 (DOI: 10.1371/journal.pbio.1001550).
Schiessl K, Kausika S, Southam P, Bush M, Sablowski R: JAGGED controls growth anisotropy and coordination between cell size and cell cycle during plant organogenesis. Current Biology 2012 (DOI: 10.1016/j.cub.2012.07.020).
