Schmid, Markus - Regulation of Plant Growth & Development by the Environment

Research

Markus Schmid sitting at his desk in his officePhoto: Fredrik Larsson

A fundamental difference between the development of plants and most animals is that the former maintains the potential to form new organs throughout their life. This capacity not only endows plants with the ability for continued growth, but also provides them with the means to rapidly and flexibly adjust to changes in their environment, resulting in a high degree of phenotypic plasticity. The aim of our research is to understand the molecular mechanisms that controls plant development, in particular the transition from vegetative to reproductive growth, in response to both endogenous and environmental stimuli.

Ambient temperature & alternative pre-mRNA splicing

An environmental signal that can have pronounced effects on plant growth and development is ambient temperature. We have recently identified a mutant in the plant model Arabidopsis thaliana that displays strong pleiotropic developmental defects in the shoot meristem and lateral organs specifically at low ambient temperature. The mutated gene, PORCUPINE, encodes a putative splice factor, suggesting that alternative splicing of pre-mRNA might be involved in modulating growth and development in response to changes in ambient temperature and might contribute to establish phenotypic plasticity in plants.

Illustration of the research done in Markus Schmid's groupAlternative splicing in the porcupine mutant

We are currently performing a number of experiments to:

  • identify the molecular mechanisms underlying the temperature-specific phenotype of the porcupine mutant
  • study the general effect of temperature on (alternative) pre-mRNA splicing and its consequences for plant growth and development
  • isolate and characterize new temperature-specific alleles affecting plant development

Regulation of flowering time & flower development

A trait that is in part controlled by ambient temperature is the induction of flowering. The transition from vegetative growth to flowering is a central event in the life cycle of plants, which requires correct timing to ensure reproductive success. In most plants flowering time is not fully deterministic but allows for some degree of phenotypic plasticity. Given that the decision to initiate flowering is made in a small number of cells in the leaf vasculature and the shoot meristem, any results obtained from complex tissues can be misleading as they likely mask tissue-specific regulatory processes. To overcome these limitations, we have adopted technologies such as INTACT and FACS to isolate nuclei from specific tissues for subsequent (epi-)genome and transcriptome analyses.

Regulation of flowering in ArabidopsisGenomics in the flower primordia

In collaboration with our colleagues at UPSC, Karin Ljung, Johannes Hanson and Ove Nilsson, we are:

  • investigating the dynamic changes of the epigenome, transcriptome, translatome, and metabolome during the switch to flowering in A. thaliana and hybrid aspen
  • isolating and characterizing novel flowering time regulators in A. thaliana
  • establishing methods for tissue- and cell-type specific “-omics” approaches in hybrid aspen

One of the first steps once plants are committed to flowering is the induction of the plant-specific transcription factor LEAFY in the incipient flower primordia. In collaboration with our colleagues Ove Nilsson (UPSC) and François Parcy (Grenoble) we are investigating how the LEAFY protein contributes to specifying the four different floral organs.

Trehalose 6 phosphate & SnRK1 signaling

The transition to flowering and subsequent seed filling are highly energy demanding processes. Thus, it is not surprising that the time of flowering is influenced by carbohydrate availability. Of particular importance in this regard is the phospho-disaccharide trehalose 6-phosphate (T6P), which plays a crucial role in carbohydrate signaling. T6P signals at least in part through the evolutionary conserved heterotrimeric kinase complex SUCROSE NON-FERMENTING1 RELATED KINASE 1 (SnRK1). We are studying how the T6P pathway and SnRK1 complex are integrated into the canonical network that regulates flowering.

Key publications:

  • Capovilla, G, Delhomme, N, Collani, S, Shutava, I, Bezrukov, I, Symeonidi, E, de Francisco Amorim, M, Laubinger, S, Schmid, M (2018) PORCUPINE regulates development in response to temperature through alternative splicing. Nature Plants 4: 534-539. doi: 10.1038/s41477-018-0176-z
  • You, Y, Sawikowska, A, Neumann, M, Posé, D, Capovilla, G, Langenecker, T, Neher, RA, Krajewski, P, Schmid, M (2017) Temporal dynamics of gene expression and histone marks at the Arabidopsis shoot meristem during flowering. Nature Communications 8: 15120, doi: 10.1038/ncomms15120
  • Posé D, Verhage L, Ott F, Yant L, Mathieu J, Angenent GC, Immink RGH and Schmid M (2013). Temperature-dependent regulation of flowering by antagonistic FLM variants. Nature 503: 414-417.
  • Wahl V, Ponnu P, Schlereth A, Arrivault S, Langenecker T, Franke A, Feil R, Lunn JE, Stitt M and Schmid M (2013). Regulation of flowering by trehalose-6-phosphate signaling in Arabidopsis thaliana. Science 339: 704-707.
  • Mathieu J, Warthmann N, Küttner F and Schmid M (2007). Export of FT protein from phloem companion cells is sufficient for floral induction in Arabidopsis. Current Biology 17: 1055-1060.