Kikukatsu Ito - Molecular Biology, Biochemistry - kikuito@ Professor United Graduate School of Agricultural Sciences Cryobiosystem Research Center, Faculty of Agriculture Group Leader Thermoregulation in plant system - Analysis of plant thermogenesis mechanism -

I. Research achievements
Since the spring of 1998, my colleagues and I have been studying the temperature sensing and control mechanisms of skunk cabbage, Symplocarpus foetidus, a unique plant species native to the cold districts in Japan. This "homeothermic plant" is able to maintain its body temperature, specifically the temperature of its spadix, in order to avoid the adverse effects of the harsh environments where the temperature can reach below freezing point. We have been carrying out research experiments to reveal the regulatory mechanisms of this unique plant that regulates its own temperature.

Our research thus far has shown that the thermal sensor of skunk cabbage, which secures its homeothermic property, is equipped in the spadix, which is also known as the organ responsible for thermogenesis. We have also found that the plant is able to respond to a temperature change of as small as ±0.9°C in order to maintain its body temperature.

What kind of mechanisms then does the skunk cabbage plant use when it transmits the information of temperature change from the spadix to the regulatory system? What molecules does the thermoregulatory components consist of? To answer these questions, we have employed molecular and biochemical analyses, as well as in silico experiments. We have begun to understand the algorithm of the temperature control system. Specifically, we have come to learn that the temperature control system of the skunk cabbage plant operates in a unique way, which can be shown by a nonlinear transfer function. We refer to this control system as the "Skunk-Cabbage-type Temperature Control System."

II. Goals in the COE Program
Skunk cabbage plants are equipped with an accurate and well-organized thermoregulatory system which allows them to control the level of thermogenesis to maintain their body temperature in response to the constantly changing surrounding temperatures. In the COE Program, we plan to carry out further analysis of the functions of biological factors associated with the thermoregulation in skunk cabbage, as well as a detailed analysis of the Skunk-Cabbage-type Temperature Control System with nonlinear properties. In addition, our intention is to explore the thermoregulatory mechanisms of other thermogenic plant species aiming to understand the universality of the system.

III. Related website
http://news7a1.atm.iwate-u.ac.jp/%7Eicg-1/Staff/Ito/ito.html

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