Plant Growth Regulation
Outline of Research and Education
Plants continuously produce organs throughout their life. This feature renders them distinct from animals, in which organ formation ceases soon after embryogenesis. We aim to understand the mechanisms of DNA polyploidization, stress response and stem cell maintenance that support sustained plant growth under changing environments. Our study will contribute to the development of technologies to increase plant biomass and food production, and to protect global plant resources.
Major Research Topics
Mechanisms for induction of DNA polyploidization
In many plant species, cells start DNA polyploidization, called endoreplication, after the cessation of cell division. Endoreplication promotes enlargement of individual cells and organs; thus, it greatly contributes to plant biomass production. While previous studies demonstrated that inhibition of cell cycle progression induces the onset of endoreplication, we recently found that chromatin decondensation can be another cause that triggers endoreplication. We are focusing on a key epigenetic factor controlling endoreplication and investigating the involvement of chromatin dynamics in the transition from cell division to DNA polyploidization. We are also developing technologies to enhance DNA polyploidization in crops and woody plants, aiming to increase food and biomass production.
Plant growth regulation in response to abiotic stress
Plant growth is usually inhibited under stressful conditions because plants need to use energy for coping with stress, rather than for organ growth. We have recently identified the signaling cascade that triggers G2 cell cycle arrest in response to complex stress, thereby functioning as a module for stress-induced growth arrest. We are studying how this cascade orchestrates expression of G2/M-specific genes and whether it is conserved among plant species. We are also generating multiple stress-tolerant crops, which can grow under changing environments, by modifying the signaling components.
Maintenance of plant stem cells
Any plant has a long life span if the developmental program is optimized, and continues to grow throughout its life. This feature is derived from persistent proliferation of pluripotent stem cells scattered throughout the plant body. We are studying the molecular mechanisms of how stem cells are maintained and replenished under DNA stress. We recently found that plant hormones play a crucial role in stem cell death and regeneration; therefore, the focus is on how hormonal signalings are coordinated to preserve stem cells. Genome maintenance in stem cells is also essential for repetitive organ formation, thus we are investigating how hormones control chromatin structure and genome integrity. Our study will facilitate understanding of mechanisms underlying toti/pluripotency, thereby contributing to the development of technologies for modifying plant architecture and enhancing regeneration in tissue culture.
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