Osmotic stress signaling in Arabidopsis
We are interested in abiotic stress signaling pathways in plants. An understanding of the plant signaling pathways responding to osmotic stress is important for both basic science and agriculture, because drought, cold and soil salinity are important problems. The pathways are also connected to sugar/energy sensing pathways. We use genetics and biochemical approaches to clarify the pathways with model plants Arabidopsis.
Plants must adjust to environmental perturbation. Drought, cold and soil salinity induce osmotic stress. One important response to osmotic stress is the accumulation of the phytohormone abscisic acid (ABA). ABA activates the SNF1-related protein kinase (SnRK)2s, which are members of SnRK superfamily. SnRK2s are also activated ABA-independently. Regulatory mechanisms of SnRKs in the pathway remain obscure. The downstream of SnRK signaling is also an important question. Especially, functions of many stress-induced genes remain unknown. The SnRK family also play important roles in sensing of photosynthesis products. Elucidating their function is a key to understand mechanisms of stress tolerance and of balancing growth with stress responses.
We are investigating the regulatory mechanisms of SnRKs. A putative regulatory protein KING1 has a potential to affect the SnRK2 activities. We are investigating in vivo function of KING1. We are also analysing a chemical affecting SnRK2.6 activity. Another member of SnRK, SnRK3 is also in our interest, especially in terms of relationship to the sugar sensing mechanism. In addition, we are interested in an abiotic stress-induced gene, which encodes a protein binding to lipid. Currently, its functions in regulation of membrane compositions and features during plant stress responses and development are investigated. We are using Arabidopsis mutant plants as well as modified plants produced with the CRISPR/Cas9 technology. Protein functions are analysed with recombinant proteins.
The United Nations reported that the current world population (7.3 billion) is expected to reach 9.7 billion by 2050 (World Population Prospects-2015 Revision). Thus, improvements in food production are urgently needed. Furthermore, climate change is predicted to affect the natural water balance in several ways, such as via salinization. Osmotic stress is also induced by freezing condition, which is another severe environment especially in Finland. Recent progresses in molecular biology make it possible to understand the molecular bases of responses and the knowledge obtained through the projects will represent an important advancement in fundamental biology. We would like to reveal molecular mechanisms of plant stress responses, which will provide clues to improve the crop productivity in the future.