2007 Annual Report
Initiated in 2002 and renewed in 2005, the project was supported with the US-former Soviet Union Program. The purpose of the program was to convert research of scientists in the Former Soviet Union countries previously involved in warfare development to civil research. The goal of this project is to develop and apply advanced biotechnology and information technology in disease management of cereal crops in Russia. The objectives of the project were to study genetic diversity of fungal pathogens and plant resistance in cereal crops, investigate emergency and development conditions of disease outbreaks on cereal crops in various regions of Russia under modern cultivation technologies and simulate epidemics, and develop effective disease forecasting systems and cereal crop disease control based on up-to-date information technologies. Disease monitoring and analyses of disease samples and historical disease data were conducted in the All-Russian Research Institute of Phytopathology and other Russian institutes. Species structures of major fungal pathogens and their importance, virulence structures of rust pathogens, and resistances of Russian cultivars were determined. Models for disease development and damage estimation were developed for stripe rust, leaf rust, powdery mildew, Fusarium head blight, and Septoria leaf and glume blotches. The new phase of the project has expanded from the European part of Russia to cover the major areas of cereal crops in the Asian part of Russia. The research revealed critical factors for these diseases, which are useful in designing effective control programs. As an ARS collaborator, my responsibilities included providing expertise in the project planning, problem solving, and overseeing the project. In 2007, we exchanged wheat germplasm and evaluated wheat genotypes that were selected from tests conducted in Russia in our experimental fields in Washington for stripe rust resistance. Since the resistant genotypes likely have genes different from those we have used in the US, they can be used to diversify resistance genes used in the US breeding programs. I reviewed the quarterly and annual reports of the project and submitted the reports in a timely manner. The objectives of the project scheduled for 2007 have been successfully accomplished.
2). Evaluated wheat and barley germplasms and breeding lines for resistance to stripe rust. For control of the rust diseases, it is critical to identify more resistant germplasms and to select resistant breeding lines of wheat and barley for resistance. In 2007, ARS scientists in Pullman, WA evaluated more than 17,000 wheat and barley entries for stripe rust resistance. From the evaluation studies, new germplasm and advanced breeding lines with stripe rust resistance were identified and new core collections of wheat and barley germplasms with resistance to stripe rust were established. These core germplasm collections can be used for identifying new genes for resistance to stripe rust. The data and information of stripe rust evaluation were provided to breeding programs that would lead to eliminating potential susceptible cultivars, and developing new cultivars with adequate resistance. This research addresses NP303 (Plant Diseases) Component Component 3 (Plant Disease Resistance), Problem Statement 3B: Disease Resistance in New Germplasm and Varieties. 3). Determined molecular mechanisms for Yr5-mediated race-specific resistance and basal defense to the stripe rust pathogen. Understanding plant–pathogen interactions is essential for effectively use of genetic resistance to control diseases like stripe rust. Yr5 represents a single R gene that confers all-stage resistance to all identified North American races of the wheat stripe rust pathogen. In a microarray study, ARS scientists in Pullman, WA used the Wheat GeneChip® to profile the changes occurring in two wheat isogenic lines that differed for the presence of the Yr5 gene after inoculation with the stripe rust pathogen. Numerous defense-related expressed genes that were important for R-gene-mediated race-specific resistance as well as basal defense were identified. Our data supported a model that links the pathogen recognition to the expression of plant defense responses. The results provide novel insights into the cellular mechanisms of wheat defense to an economically important pathogen, and the findings will be useful for the development of durable resistant cultivars. This research addresses NP303 (Plant Diseases) Component 3 (Plant Disease Resistance), Problem Statement 3A: Mechanisms of Plant Disease Resistance.
Babcock, C., Chen, X., Crous, P.W., Dugan, F.M., Goates, B., Green, P.N. 2007. Plant germplasm centers and microbial culture collections: A users guide to key genetic resources for plant pathology. Plant Dis. 91:476-484.
Chen, X. 2007. Challenges and solutions for stripe rust control in the United States. Australian Journal of Agricultural Research 58:648-655.
Lin, F., Chen, X. 2007. Genetics and molecular mapping of genes for race-specific all-stage resistance and non-race specific high-temperature adult-plant resistance to stripe rust in spring wheat cultivar Alpowa. Theor. Appl. Genet. 114:1277-1287.
Ling, P., Meinan, W., Chen, X., Garland Campbell, K.A. 2007. Construction and characterization of a full-length cDNA library for the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici). BMC Genomics 8:145.
Nirmala, J., Dahl, S., Steffenson, B., Kannangara, C.G., Von Wettstein, D., Chen, X., Kleinhofs, A. 2007. Proteolysis of the barley receptor-like protein kinase Rpg1 by a proteasome pathway is required for Rpg1 mediated stem rust resistance. PNAS 104:10276-10281.
Wan, A.M., Chen, X., He, Z.H. 2007. Wheat stripe rust in China. Australian Journal of Agricultural Research 58:605-619.
Yan, G.P., Chen, X. 2007. Molecular Mapping of the rps1.a Recessive Gene for Resistance to Stripe Rust in BBA 2890 Barley. Phytopathology 97:668-673.
Chen, X., Wood, D.A. 2006. Reduction of stripe rust severities on spring wheat by seed treatment with fungicides, 2005. F&N Tests 61:ST010.
Chen, X., Wood, D.A. 2006. Control of stripe rust of winter wheat with foliar fungicides, 2005. F&N Tests 61:CF023.
Chen, X., Wood, D.A. 2006. Control of stripe rust of spring barley with foliar fungicides, 2005. F&N Tests 61:CF024.
Chen, X., Wood, D.A. 2007. Control of stripe rust of winter wheat with foliar fungicides, 2006. Plant Disease Management Reports. 1:FC108.
Chen, X., Wood, D.A. 2007. Control of stripe rust of spring wheat with foliar fungicides, 2006. Plant Disease Management Reports. 1:FC109.
Chen, X., Wood, D.A. 2007. Fungicide seed treatments for reducing yield losses caused by stripe rust on spring barley, 2006. Plant Disease Management Reports 1:ST005.
Chen, X., Wood, D.A. 2007. Fungicide seed treatments for reducing yield losses caused by stripe rust on spring wheat, 2006. Plant Disease Management Reports. 1:ST006.
Chen, X., Wood, D.A. 2007. Fungicide seed treatments for reducing yield losses caused by stripe rust on winter wheat, 2006. Plant Disease Management Reports. 1:ST007.
Rossi, C., Cuesta-Marcos, A., Vales, I., Gomez-Pando, L., Orjeda, G., Wise, R.P., Sato, K., Hori, K., Capettini, F., Vivar, H., Chen, X., Hayes, P. 2006. Mapping multiple disease resistance genes using a barley mapping population evaluated in Peru, Mexico, and the USA. Molecular Breeding 18:355-366.