The selection of a sugar for transport and storage of carbon in plants

Maheshwari, Ramesh and Veluthambi, Karuppanan (2011) The selection of a sugar for transport and storage of carbon in plants. In: Current Science (Bangalore), 101 (2). pp. 189-193.

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Abstract

Sugars perform two vital functions in plants: as compatible solutes protecting the cell against osmotic stress and as mobile source of immediate and long-term energy requirement for growth and development. The two sugars that occur commonly in nature are sucrose and trehalose. Sucrose comprises one glucose and one fructose molecule; trehalose comprises two glucose molecules. Trehalose occurs in significant amounts in insects and fungi which greatly outnumber the plants. Surprisingly, in plants trehalose has been found in barely detectable amounts, if at all, raising the question `why did nature select sucrose instead of trehalose as the mobile energy source and as storage sugar for the plants'? Modelling revealed that when attached to the ribbon-shaped beta-1,4 glucan a trehalose molecule is shaped like a hook. This suggests that the beta-1,4 glucan chains with attached trehalose will fail to align to form inter-chain hydrogen bonds and coalesce into a cellulose microfibril, as a result of which in trehalose-accumulating plant cells, the cell wall will tend to become leaky. Thus in plants an evolutionary selection was made in favour of sucrose as the mobile energy source. Genetic engineering of plant cells for combating abiotic stresses through microbial trehalose-producing genes is fraught with risk of damage to plant cell walls.

Item Type:	Journal Article
Publication:	Current Science (Bangalore)
Publisher:	Indian Academy of Sciences
Additional Information:	Copyright of this article belongs to Indian Academy of Sciences.
Keywords:	Abiotic stress;cell wall;cellulose;Cuscuta;genetic engineering;trehalose
Department/Centre:	Division of Biological Sciences > Biochemistry
Date Deposited:	30 Sep 2011 06:12
Last Modified:	30 Sep 2011 06:12
URI:	http://eprints.iisc.ac.in/id/eprint/40787

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