Functional genomics and mapping of stress regulated genes in cereals

NSERC Genomics program.

Applicants: Fathey Sarhan (UQAM), Patrick Gulick (Concordia), Brian Fowler (University of Saskatchewan).

Genomic analysis will make a dramatic contribution to the analysis and genetic engineering of cold tolerance in wheat, one of Canada's and the world's most important crops. Conventional breeding to improve freezing tolerance (FT) in wheat has been slow and has reached a plateau that is short of the optimal hardiness for the Canadian climate. This is attributed to our lack of understanding of the genetic factors that compose and regulate this complex multigenic trait.

Using molecular approaches, several low temperature (LT) regulated cDNA clones were isolated from a "freezing-tolerant" wheat strain in our laboratory. The expression of some of these genes was shown to be closely correlated with the capacities of wheat genotypes and cereals to develop FT. Thus, these genes and their products may have an important function in conferring FT.

In addition, molecular studies have shown that a region on chromosome 5A of winter wheat regulates this differential expression, in part. Therefore, the basic goal of this research is to use current methods and technologies of functional genomics to scale up the identification of structural and regulatory genes that are involved during the cold acclimation (CA) process and to determine their function. This will permit us to evaluate their potential use as tools to manipulate and improve FT in cereals and other species. The short-term objectives of this proposal could be summarized as follows:

1. Build cDNA libraries containing a representative sampling of genes expressed during CA and select clones representing differentially expressed genes and low abundance transcripts.
2. Sequence these clones so as to generate expressed sequence tags (ESTs).
3. Use DNA microarrays on nylon membranes and glass to quantify gene expression in response to abiotic stresses and begin a more thorough analysis of gene expression patterns and function in different populations of wheat and other grasses.
4. Map key LT-regulated ESTs and produce unique wheat genetic material that will be used in the future for investigating the gentic cascades responsible for plant response to LT.
5. Evaluate the potential of selected regulators