Research・Cold Adaptation Biology Laboratory

【Research Background】

Plants are exposed to various stresses in their natural environment. They range from temperature and humidity to light, soil composition, and moisture conditions, and plants are affected by these stresses. Although these stresses constantly threaten the survival of plants, plants also sense and transmit these stresses and have acquired mechanisms to respond and adapt to these stresses over their long history. Among these stresses, our research field deals with low temperatures in particular. In Morioka City, Iwate Prefecture, the average temperature is well below freezing in winter, which has a significant impact on the wild plants that live in this area. Even today, with the development and advancement of various agricultural technologies, our agriculture is greatly affected by low temperatures. Even here in the Tohoku region, the frequent occurrence of cold weather has serious adverse effects each time, and it remains one of the major problems that have yet to be solved in order to maintain stable agriculture. In order to solve these problems, and eventually to increase food production and cope with population growth, it is important to understand the existing mechanisms of plants to acquire tolerance to low temperature (freezing) and to apply these mechanisms. The premise for this is the need to understand the complex and complicated mechanisms that include the recognition of low temperatures, signal transduction to appropriate locations and regions, various physiological and morphological changes in response to these signals, the subsequent expression of stress response mechanisms, and finally the acquisition of low-temperature tolerance (or freezing tolerance).

【Research Activities】

A major theme of our research field is the elucidation of the cold acclimation mechanisms in plants. The cold acclimation mechanism is one of the key mechanisms by which plants sense environmental changes and increase their cold tolerance (freezing tolerance). We are studying this cold acclimation mechanism by focusing on genetic changes mediated by transcription factors, changes in intracellular osmotic concentration and protective activity of intracellular structures by compatible solutes, changes in the composition of lipids and proteins in the cell membrane that affect cell membrane fluidity, and calcium-dependent cell membrane repair mechanisms against freezing injury. We are also interested in what happens to plants under actual low temperature and freezing conditions? We are also studying what happens to plants under actual low-temperature and freezing conditions from the viewpoint of injury or tolerance mechanisms, and from the three levels of cell, tissue, and plant body. In particular, we have recently been focusing on mechanical freezing stress. Freezing stress imposes two qualitatively different physical stresses on cells, namely mechanical stress and dehydration stress, but research to date has focused primarily on dehydration stress, with little research on mechanical stress. To date, we have successfully obtained novel insights into the effects of freezing mechanical stress and its tolerance mechanisms. On the other hand, the improvement of techniques for cell observation under freezing using optical microscopy was essential for this novel finding. High-resolution microscopic observation under freezing is extremely difficult because the refractive index of ice crystals differs from that of water. Even now, although we have made some improvements over the past, we are still unable to achieve high-resolution observation. We will continue to improve our microscopic observation techniques to obtain detailed information on cell physiology under freezing conditions.

【Research topics】

・Universality of calcium-dependent freezing tolerance in plants.
・Analysis of plasma membrane microdomains in barley and triticale during cold acclimation.
・Elucidation of desiccation tolerance mechanisms in CRES-T homolines.
・Correlation between dynamin-related proteins and phyllotaxis during cold acclimation in Arabidopsis thaliana.
・Plant cell dynamics during cold acclimation and deacclimation.
・Endoplasmic reticulum dynamics during freezing and thawing of plant cells
・Freezing tolerance test and plasma membrane proteome analysis of novel rice model plants
・Proteome analysis of Arabidopsis thaliana during cold acclimation and deacclimation
・Reception of cold stimuli and intracellular calcium ion dynamics in plant cells
・Light condition and temperature range dependent cold acclimation process
・Physiological conditions and molecular mechanisms of new acclimation with freezing (Second-phase freezing accliamtion)

Faculty of Agriculture, 3-chome-18-8 Ueda, Morioka, Iwate(google map)