Cristobal Uauy from Department of Crop Genetics, John Innes Centre.
“What domestication missed: exploiting wild emmer to improve wheat”
Department of Plant Sciences Large Lecture Theatre, University of Cambridge
Wild emmer wheat (Triticum turgidum ssp. dicoccoides; DIC) has long been recognized as a potential source of valuable alleles for a series of important agronomic traits in wheat. We have recently isolated two such genes from wild emmer through positional cloning. Gpc-B1 is a NAC transcription factor that improves the efficiency of mineral remobilization from senescing leaves to grains. The wild emmer allele accelerates senescence by 2-3 days and increases grain N, Zn and Fe concentration by 10-15%. Closely linked to Gpc-B1 (0.3 cM) we identified Yr36, a gene that confers non race-specific or partial resistance to Puccinia striiformis f. sp. tritici (PST), the yellow rust pathogen. This gene encodes a kinase-START domain protein, representing a novel gene architecture, and its resistance was shown to be temperature dependant. Both Gpc-B1 and Yr36 are either non-functional or deleted in all cultivated durum and bread wheat varieties. However, backcross introgressions of the DIC segment including Gpc-B1 and Yr36 confers consistent increases in grain protein and micronutrient concentration in tetraploid and hexaploid wheat varieties as well as improving resistance to PST in susceptible cultivars. This suggests that the Gpc-B1 and Yr36 wild emmer alleles have the potential to contribute to the improvement of wheat nutritional value and yellow rust resistance in a wide range of germplasm. During the seminar we will discuss strategies to reduce the threshold for gene cloning in polyploid wheat and the approaches and tools used for functional characterization of these genes. Overall, our work with emmer argues for the importance of using wild species to discover and recover valuable alleles for modern agriculture. This will become increasingly important as we face new challenges to secure a sustainable food supply in a changing environment.
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