Location: Genomics and Gene Discovery
2012 Annual Report
Mapping and map-based cloning of agriculturally and economically important traits for crop wheat improvement remain a great challenge due to its large and complex genome. For the same reason, complete sequencing of wheat genome still represents a daunting task. Generation of valuable genomics resources could greatly facilitate various aspects of wheat research. In collaborative efforts, various high resolution maps including genetic, physical, and radiation hybrid maps have been generated. These maps are widely accessible to the wheat research community. The development of bacterial artificial chromosome-based physical map for the wheat D genome provides a foundation for future sequencing of the entire wheat D genome.
The high molecular weight glutenin subunit (HMW-GS) proteins are major determinants of the quality of food products made from wheat flours, yet the mechanisms of how they influence dough processing properties are still poorly understood. Understanding the molecular bases of how these proteins unique to wheat function will provide new knowledge in wheat. To this end, scientists at WRRC screened wheat mutant lines that are deficient in genes encoding the HMW-GS to understand the changes of chemical and physical properties associated with the lack of expression of individual HMW-GS in mutant lines. This is the first time that the role of individual HMW-GS has been examined in vivo. In addition, the Unit published an extensive study of the roles of different regions of the HMW-GS play in dough quality and identified factors in dough characteristics.
The substantial increases of wheat yield were made possible by introducing dwarfing traits into modern wheat cultivars. Therefore, the dwarf trait in crops has contributed greatly to the sustainable food supply demanded by the increasing world population. A large genomic region spanning a severe dwarfing gene region has been sequenced. Comparative analysis with rice, Brachypodium, and sorghum indicated a high sequence conservation among grass species. New cis-regulatory elements that control/regulate the expression of the dwarfing gene were identified, facilitating future biotechnological application of these regulatory elements for crop improvement.
The on-going project to develop and utilize Brachypodium as a model system for Triticeae research for grain quality and other traits has progressed significantly. Over 10,000 T-DNA insertional mutant lines have been generated for functional genomics study in this model species. Brachypodium genes involved in lignin biosynthesis has been functionally characterized to understand the cell wall structure and function. In addition, a viral resistance gene has been identified and mapped in Brachypodium. This is the first demonstration that Brachypodium can be exploited for isolation of resistance genes for important crops.
Duan, J., Wu, J., Gu, Y.Q., Kong, X. 2012. New cis-regulatory elements in the Rht-D1b locus region of wheat. Functional and Integrative Genomics. Available at: http://rd.springer.com/article/10.2007/s10142-012-0283-2. DOI 10.1007/s10142-012-0283-2.
Chingcuanco, D.L. 2012. Isolation and characterization of EMS-induced Dy10 and Ax1 high molecular weight glutenin subunit deficient mutant lines of elite hexaploid wheat (Triticum aestivum L.) cv. Summit. Journal of Cereal Science. 56:296-299 doi: 10.1016/j.jcs.2012.06.009.
Kumar, A., Bassi, F.M., Gu, Y.Q., Dogramaci, M., Kianian, S. 2012. DNA repair and crossing over favor similar chromosome regions as discovered in radiation hybrid of Triticum. Biomed Central (BMC) Genomics. doi 10.1186/1471-2164-13-339.
Wu, J., Gu, Y.Q., Hu, Y., You, F.M., Dandekar, A.M., Leslie, C.A., Aradhya, M.K., Dvorak, J., Luo, M. 2011. Characterizing the walnut genome through analyses of BAC end sequences. Plant Molecular Biology. 78:95-107.
Chingcuanco, D.L., Fowler, B.D. 2012. Genotype dependent burst of transposable element expression in crowns of hexaploid wheat (Triticum aestivum L.) during cold acclimation. Comparative and Functional Genomics. Available at: http://www.hindawi.com/journals/cfg/2012/232530/. doi:10.1155/2012/232530..
Li, Y., Xioa, J., Wu, J., Gu, Y.Q., Kong, X. 2012. A tandem segmental duplication (TSD) in the green revolution gene Rht-D1b region underlies plant height variation. New Phytologist. doi: 10.1111/j.1469-8137.2012.04243.x.
Anderson, O.D., Bekes, F., D'Ovidio, R. 2011. Effects of specific domains of high-molecular-weight glutenin subunits’ on dough properties by an in vitro assay. Journal of Cereal Science. 54:280-287.
Anderson, O.D., Bekes, F. 2011. Incorporation of high-molecular-weight glutenin subunits into doughs using 2 gram mixograph and extensigraphs. Journal of Cereal Science. 54:288.