Celluiar and subcellular membranes are one of the primary sites of injury in pIants exposed to environmentai stress. Besides genes for enzymes of osmoIyte biosynthesis or other rnolecules involved in protecting membranes, such as dehydrins or lea proteins, the maintenance of proper membrane functions under stress it has been associated to genes involved in changes in lipid composition. We have demonstrated that changes in growth temperatures regulate the level of expression of two desaturase genes, encoding for a delta-9 and a delta-12 desaturase, isolated from a potato cDNA library. Increase in temperature caused down-regulation of des 9, while des 12 was actively expressed by decreasing the temperature. Low temperature induced active transcription of des 12 in cold-accIimated plants of a cold tolerant potato species. Down-regulation of both genes was associated to a decrease in membrane unsaturated fatty acid in potato cells subjected to water deficit. Taken together our data demonstrate that this cIass of genes is regulated by external factors and that the manipulation of the their expression could improve tolerance to environmental stress, through changes in membrane lipid composition. The effects of over- or under-expression of such genes in transgenic potato plants will be presented and discussed.
Regulation of Acyl-desaturase genes by enviromantal stresses
Costa A;
1997
Abstract
Celluiar and subcellular membranes are one of the primary sites of injury in pIants exposed to environmentai stress. Besides genes for enzymes of osmoIyte biosynthesis or other rnolecules involved in protecting membranes, such as dehydrins or lea proteins, the maintenance of proper membrane functions under stress it has been associated to genes involved in changes in lipid composition. We have demonstrated that changes in growth temperatures regulate the level of expression of two desaturase genes, encoding for a delta-9 and a delta-12 desaturase, isolated from a potato cDNA library. Increase in temperature caused down-regulation of des 9, while des 12 was actively expressed by decreasing the temperature. Low temperature induced active transcription of des 12 in cold-accIimated plants of a cold tolerant potato species. Down-regulation of both genes was associated to a decrease in membrane unsaturated fatty acid in potato cells subjected to water deficit. Taken together our data demonstrate that this cIass of genes is regulated by external factors and that the manipulation of the their expression could improve tolerance to environmental stress, through changes in membrane lipid composition. The effects of over- or under-expression of such genes in transgenic potato plants will be presented and discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
