Cuticular wax biosynthesis

MOLECULAR BIOLOGY OF GENES INVOLVED IN CUTICULAR WAX BIOSYNTHESIS... 

Despite the sequence similarity between the CERl and GLl proteins, their biochemical function is unclear since mutations at each gene affect the respective cuticles differently. CERl has been predicted to code for an aldehyde decarbonylase (Aarts et al., 1995), an enzyme required for the production of the alkane fraction of the cuticular waxes of this species. Indeed, mutations at the CERl locus cause an enrichment of the aldehydes and a depletion of the alkanes and alkane-derived metabolites (ketones and secondary alcohols). In maize however, its unlikely that gll codes for an aldehyde decarbonylase. This conclusion is based upon the fact that alkanes account for a very small portion of the cuticular waxes of wild-type maize seedlings (about 1%), and because mutations at the gll locus qualitatively and/or quantitatively affect the accumulation of fatty aldehydes, alcohols, and the ester components of the maize cuticular waxes. Therefore, even though the GLl and CERl proteins share similar structures, they may in fact perform different functions in cuticular wax biosynthesis. Alternatively, both proteins may perform similar, but as yet unidentified, function(s). 

Molecular Biology of Genes Involved in Cuticular Wax Biosynthesis. 

There is evidence suggesting that many of the thiocarbamates reduce the production of cuticular wax and interference with lipid biosynthesis which probably represents the primary mode of action of these herbicides. 

Kunst, L., Samuels, A.L. 2003. Biosynthesis and secretion of plant cuticular wax. Prog. Lipid Res. 42 51-80. 

Szafranek, B.M. S3mak, E.E. Cuticular waxes from potato (Solanum tuberosum). Ph3ftochemistry 2006, 67, 80-90. Nes, W.D. Nichols, S. D. Phytosterol biosynthesis pathway in Mortierella alpina. Phytochemistry 2006, 67,... 

This group of herbicides has many diverse modes of action. Most of these herbicides are absorbed by the plant roots and are translated in the xylem. There is evidence suggesting that many of the thiocarbamates reduce the production of cuticular wax and interfere with lipid biosynthesis, which probably represents the primary mode of action of these herbicides. 

In plant tissues Cieo can undergo some other modifications (Figure 3), namely elongation, hydroxylation, oxidation, epoxydation, reduction, oxidative decarboxylation, etc. As a result of these modifications many different lipophilic substances are produced. Among these substanees very long-chain FAs (VLCFAs, C>2o), different unusual FAs (hydroxy-, epoxy-, acetylenic, dicarboxylic), fatty aldehydes and alcohols, hydrocarbons, oxilipins, etc. are formed. Some of them are present in plants in free form (are embedded in the complex cuticular lipid matrix or as a components of epicuticular waxes), the others are used as a substrates for more complex lipids and lipid polymers biosynthesis (see below). 

Holloway PJ. Structure and histochemistry of plant cuticular membranes an overview. In Cutler DF, Alvin KL, Price CE, editors. The Plant Cuticle. London Academic Press, 1982 139-165. Kolattukudy PE. Plant waxes. Lipids. 1970 5 (2) 259-275. Kolattukudy PE, Walton TJ. Structure and biosynthesis of the hydroxy fatty acids of cutin in Viciafaba leaves. Biochemistry 1972 11(10) 1897-1907. 

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