Regulation by Gravity of Ferulate Formation in Cell Walls of Rice Seedlings (Ferulate) - 11.19.14

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Science Objectives for Everyone
Ferulate tests the hypothesis that microgravity modifies ferulic acid thereby decreasing the mechanical strength of cell walls.

Science Results for Everyone

Does microgravity weaken plant cell walls? The Ferulate experiment aims to answer this question by testing whether space reduces the levels of ferulic acid (a chemical related to vanillin, the flavorful ingredient of vanilla beans)  in cell walls and therefore decreases cell wall strength in rice and wheat plants.   Results suggest that stronger gravity increases the rigid network structures within wheat cell wall, contributing to more stable cell walls. Results also suggest that certain genes  and enzyme activities are involved in the formation of cell wall ferulate networks in rice.

The following content was provided by Kazuyuki Wakabayashi, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Japan Aerospace and Exploration Agency (JAXA).

Experiment Details


Principal Investigator(s)

  • Kazuyuki Wakabayashi, Ph.D., Osaka City University, Osaka, Japan

  • Co-Investigator(s)/Collaborator(s)
  • Takayuki Hoson, Ph.D., Osaka City University, Osaka, Japan
  • Koichi Soga, Ph.D., Osaka City University, Osaka, Japan
  • Hidekazu Tanimoto, Nagoya City University, Japan
  • Kiyohide Kojima, Niigata University, Japan
  • Genji Kamata, AES, Japan
  • Atsushi Higashibata, JAXA, Japan

  • Developer(s)
    Information Pending
    Sponsoring Space Agency
    Japan Aerospace Exploration Agency (JAXA)

    Sponsoring Organization
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    Research Benefits
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    ISS Expedition Duration
    March 2010 - September 2010

    Expeditions Assigned

    Previous ISS Missions
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    Experiment Description

    Research Overview

    • The Ferulate Experiment tests the hypothesis that microgravity decreases the mechanical strength of cell walls of rice plants by modifying the levels of abscisic acid.

    • The polysaccharide composition of the cell wall in gramineous plants, such as rice, maize, wheat, and barley, is distinguished from that in dicotyledons, such as Arabidopsis, pea, and mung bean, which have been used in many space experiments.

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    Space Applications
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    Earth Applications
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    Operational Requirements
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    Operational Protocols
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    Results/More Information

    The sterilized rice seeds were planted on an agar medium, placed in a black polycarbonate culture dish, and stored in a refrigerator to prevent germination before and during the flight until the start of growth experiment in the Kibo module of the International Space Station (ISS). In orbit, seeds were transferred to the Cell Biology Experiment Facility (CBEF) and allowed to germinate and grow under 1G and microgravity conditions in the dark. After incubation, seedlings were frozen and returned to Earth. The CBEF has 2 incubator compartments, a microgravity compartment and an artificial gravity compartment with a centrifuge. The facility allowed for plant samples to be grown under microgravity and artificial 1 G conditions simultaneously in orbit.      The germination rate was more than 90% in both in-orbit 1G and microgravity conditions. The length of 1G-grown rice shoots substantially increased from day 4 to day 5. Microgravity did not affect the shoot growth. Analysis of the mechanical properties in the cell walls showed that shoot cell walls obtained from seedlings grown under microgravity conditions for 5 days were loosened as compared with those under 1G conditions. On day 5, the levels of cell wall-bound mono-phenolic acids, such as ferulic acid (FA), in microgravity grown shoots were almost comparable to those in 1 G-grown shoots, while the levels of diferulic acid (DFA) were lower in microgravity grown shoots. Furthermore, cell wall peroxidases activity measurements showed that the activity obtained from micro G-grown shoots was lower than that from 1G-grown shoots. These results suggest that microgravity conditions reduce the activity of cell wall peroxidases in rice shoots, resulting in the suppression of DFA formation, which in turn, may cause the reduction of mechanical strength in shoot cell walls.

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    Results Publications

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    Ground Based Results Publications

      Wakabayashi K, Soga K, Hoson T.  Modification of cell wall architecture in gramineous plants under altered gravity condition. Biological Sciences in Space. 2009; 23(3): 137-142. DOI: 10.2187/bss.23.137.

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