Marine Biotechnology

, Volume 7, Issue 5, pp 407–415

Salt-Regulated Mannitol Metabolism in Algae


DOI: 10.1007/s10126-005-0029-4

Cite this article as:
Iwamoto, K. & Shiraiwa, Y. Mar Biotechnol (2005) 7: 407. doi:10.1007/s10126-005-0029-4


Mannitol, one of the most widely occurring sugar alcohol compounds, is found in bacteria, fungi, algae, and plants. In these organisms the compound acts as a compatible solute and has multiple functions, including osmoregulation, storage, and regeneration of reducing power, and scavenging of active oxygen species. Because of the diverse functions of mannitol, introducing the ability to accumulate it has been a hallmark of attempts to generate highly salt-tolerant transgenic plants. However, transgenic plants have not yet improved significantly in their salt tolerance. Recently, we purified and characterized 2 enzymes that biosynthesize mannitol, mannitol-1-phosphate dehydrogenase (M1PDH) and mannitol-1-phosphate-specific phosphatase, from the marine red alga Caloglossa continua, which grows in estuarine areas where tide levels fluctuate frequently. The activation of Caloglossa M1PDH is unique in that it is regulated by salt concentration at enzyme level. In this review we focus on the metabolism of mannitol, mainly in marine photosynthetic organisms, and suggest how this might be applied to producing salt-tolerant transgenic plants.

Key word

algae halotolerant mannitol metabolism mannitol dehydrogenase mannitol-1-phosphatase salt-regulation 

Copyright information

© Springer Science+Business Media, Inc. 2005

Authors and Affiliations

  1. 1.Functional BiosciencesGraduate School of Life and Environmental Sciences, University of TsukubaTsukubaJapan

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