Abiotic Stress

Cotton Salt Stress Microarray Summary (Udall)

Detailed description and current work

Environmental abiotic stresses, such as high soil salinity, have adverse effects on plant growth and seed production. The underlying molecular genetics in cotton contributing to salt tolerance remains largely unknown. Cotton DNA microarrays simultaneously assay the expression levels of thousands of genes. When separately hybridized with RNA collected from salt-treated tissues and non-treated tissues, the transcription levels of some genes are up or down regulated as a response mechanism to this type of stress. In this project, we compared gene expression profiles of five evolutionary recent allopolyploid cottons (G. hirsutum, G. barbadense, G. tomentomsum, G. darwinii, and G. mustilinum). For each species, a direct comparison between salt treatment and control conditions were made using microarrays. This experiment will uncover cotton genes and pathways that are responsive to salt and it will provide a unique molecular perspective into the evolution of salt tolerance in Gossypium.  Initial results to data are summarized in this poster, a detailed description is found here and current progress can be seen on our lab wiki.

Quinoa Salt Stress Microarray Summary (Udall)

Detailed description and current work

Plants respond to abiotic stress through transcriptional gene regulation.  Large amounts of comparative transcriptional profiles have been generated for two model plants Arabidopsis thaliana and Thellugiella halophila in response to salt stress.  However, some plants may respond differently to abiotic stress than these two model species of the Brassicaceae family.  Indeed, salt tolerance may have independently evolved through multiple physiological avenues. Like T. halophila, Chenopodium quinoa (quinoa) also has extreme tolerances to salt concentrations and it is grown in the Andean Altiplano as a staple crop.  Quinoa, a member of the Chenopodiaceae family, may have distinct cellular mechanisms conferring its salt-tolerance when compared to A. thaliana or T. halophila.  Here, we propose to measure quinoa basic physiological responses to salt stress and directly compare those measurements to the responses of T. halophila.  We will also measure quinoa gene expression levels in response to salt treatment.  The combination of these two approaches will provide a foundation to understanding how diverse families of plants have evolved mechanisms to tolerant high saline growth conditions.

Quinoa Salt Tolerance (SOS1; Maughan)

Some varieties of quinoa are remarkably well adapted to adverse environmental conditions such as salinity, drought and cold. To further our understanding the genetic basis for this adaptation, two separate components for research are being pursued.  First, the sequence of candidate genes are being determined. the Salt Overly Sensitive 1 (SOS1) gene of A. thaliana has been shown to play a role in salt sensitivity for this model plant. Homologous quinoa genes are being identified based on their similarity to A. thaliana. Once the quinoa cDNA homolog was cloned it was hybridized to BAC libraries to identify the full-length gene sequence as well as its genomic sequence (introns and UTRs).  Currently research of this gene includes functional complementation of the C. quinoa homolog in an A. thaliana sos1 mutant and identification of allelic variants that may confer resistance in quinoa to high salt levels in the soil.