Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress

Authors: Upchurch, Robert

Submitted to: Biotechnology Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/30/2007
Publication Date: 6/15/2008
Citation: Upchurch, R.G. 2008. Fatty acid unsaturation, mobilization, and regulation in the response of plants to stress. Biotechnol. Lett. 30:967-977.

Interpretive Summary: Plants commonly encounter environmental stresses such as low or elevated temperature, exposure to salt, drought, and (less commonly) heavy metals, as well as pathogen and insect attack, sometimes simultaneously. Since plants lack mobility they cannot avoid exposure to stresses in their environment, but must adapt to them in other ways. Fatty acids are crucial components of cellular membranes, suberin, and cutin which provide structural barriers to the environment. Fatty acids contribute to inducible stress resistance through the remodeling of membrane fluidity and the release through lipase activity of a-linolenic acid. Linolenic acid is itself a signaling molecule and the precursor for phyto-oxylipin biosynthesis. The ability to adjust membrane lipid fluidity by changing unsaturate levels is a feature of stress acclimating plants provided mainly by the regulated activity of fatty acid desaturases. Adjustment of membrane fluidity maintains an environment suitable for the function of critical integral proteins, such as the photosynthetic machinery, during stresses. Fatty acids play a central role in the interaction of fungi with oilseeds. Evidence suggests that plant fatty acid (and oxylipin) species signal and regulate fungal development, pathogen colonization of oilseeds, and mycotoxin production.

Technical Abstract: Stress acclimating plants respond to abiotic and biotic stress by remodeling membrane fluidity and the release of a-linolenic from membrane lipid. The adjustment of membrane lipid fluidity occurs through changes in unsaturated fatty acid levels, a function provided by the regulated activity of fatty acid desaturases. Adjustment of membrane fluidity maintains an environment suitable for the function of critical integral proteins during stress. Linolenic acid, released from membrane lipid by regulated lipase activity, is itself a stress signaling molecule and the precursor for phyto-oxylipin biosynthesis. Fatty acids regulate, at least in part, fungal pathogen development, pathogen colonization of oilseeds, and mycotoxin production.