IBG-2 Seminar: Delphine Fleury (Adelaide)

Seminar IBG-2: Pflanzenwissenschaften

Combining -omics for positional cloning of QTL controlling drought tolerance in wheat

Dr. Delphine Fleury

Australian Center for Plant Functional Genomics ACPFG, Adelaide, Australia

Tolerance to drought is a quantitative trait, with a complex phenotype, often confounded by plant phenology. Breeding for drought tolerance is further complicated since several types of abiotic stress, such as high temperatures, high irradiance and nutrient toxicities or deficiencies can challenge crop plants simultaneously.

The genetic control of yield in difficult environments is generally expected to be of low heritability, polygenic and many of the key loci show epistatic rather than additive effects. In wheat and barley, genetic improvement is impaired by the size (respectively 16 Gb and 5 Gb) and the complexity of their genomes (80% high repetitive DNA content and allohexaploid nature of bread wheat).

A strategy combining forward genetics, physiology and omics and has been developed at the Australian Centre for Plant Functional Genomics to identify genes controlling tolerance to drought in wheat. We targeted a specific environment and selected appropriate germplasms adapted to it. Segregating populations were created and studied for QTL analysis and positional cloning. Phenotyping protocols have been developed to accurately measured drought tolerance and identify stable QTL. Genome-wide functional analyses such as microarrays revealed key cellular processes and regulatory networks that control plant growth under drought. Physical mapping and next-generation technologies are now being used to target specific regions for gene isolation.