Genomic analysis of the polyamine-dependent response to abiotic stress.

The response of Arabidopsis plants with modifications in polyamine metabolism to different abiotic stress situations (salinity, drought, osmotic stress, or ozone) will be analyzed. The analysis will be carried out using transgenic plants overexpressing some of the genes in the biosynthetic pathway or mutants deficient in these genes. Global transcriptome changes will be determined by hybridization with DNA microarrays. A database will be created to correlate tolerance to stress, polyamine levels, the relationship between different polyamines, and transcripts whose expression significantly varies compared to wild-type plants subjected to the same conditions.

Analysis of genetic variability in the response to abiotic stress and polyamine metabolism in different Arabidopsis ecotypes.

Tolerance to the same types of abiotic stress will be analyzed in a set of approximately 100 different Arabidopsis varieties and ecotypes, and the physiological and molecular responses of the different varieties will be compared. To do this, LT50 (a stress tolerance parameter) and polyamine levels will be determined under both normal and stress conditions.

Genomic analysis of the abiotic stress response in Arabidopsis ecotypes selected for their differential stress characteristics.

Global transcriptome changes will be determined using DNA microarrays. A database will be created to correlate stress tolerance, polyamine levels, the relationship between the different polyamines, and transcripts whose expression significantly differs from the average level of the ecotypes analyzed. The database will include polyamine levels for each ecotype; stress tolerance markers will be selected from this and the database developed in the previous section. The expression levels of the genes selected as markers will be determined by qRT-PCR for all ecotypes.

Development of markers for agronomically important plants.

Data obtained from Arabidopsis will be used to develop markers in crops such as solanaceous species (tomato, potato) or cereals. Polyamine levels and “marker” transcripts of stress will be determined in different varieties to establish selection criteria for crops to be grown under unfavorable environmental conditions.