| Position: Assistant Professor Education: Ph.D., 1992, Huazhong Agricultural University, P.R. China Voice: (240) 314-6480 Email: xiao@umbi.umd.edu Home page: http://shadygrove.umbi.umd.edu/xiaogroup/ Mailing info CBR Faculty Directory | Research OverviewDisease Resistance in Plants Disease resistance in plants in part depends on the ability of the plant cells to recognize the invading pathogens. Since such recognition involves recognition of specific molecules, it is often under genetic control. Leucine-Rich Repeats One major class of disease resistance genes, or R genes, includes members of the leucine-rich repeats (LRR) gene family, including ancient families thought to be present in all species of plants. Transgenic Plants Transgenic plants are genetically-modified organisms whose genetic material has been altered by recombinant DNA technology, either for research purposes or for agricultural or other human purposes. Arabidopsis Arabidopsis is a model organism that is often subject to laboratory experimentation. | Research DescriptionResearch Areas: Pathobiology, Genome Sciences Research Specialties: Molecular mechanisms of plant programmed cell death and disease resistance Plant disease resistance genes (R) recognize the invading pathogens and subsequently trigger defense responses. In most cases, plant resistance conferred by R genes is associated with hypersensitive response (HR), which is thought to be a form of programmed cell death (PCD) similar to apoptosis of animal cells. Most characterized R genes encode proteins containing a nucleotide-binding domain and leucine-rich-repeats (NB-LRR) and are believed to be of ancient origin and present in all plant species. We isolated a novel type of R gene RPW8 from Arabidopsis thaliana that confers broad-spectrum resistance in Arabidopsis to powdery mildew (Erysiphe), a very important biotrophic fungal pathogen capable of infecting more than 9000 plant species. Interestingly, although RPW8 differs from other classes of R genes in protein structure and disease spectrum, the defense responses mediated by RPW8 are similar to those mediated by other R genes, and several conserved signaling components such as EDS1, PAD4, EDS5, SGT1 and NPR1, known to be recruited by NBS-LRR genes, are also required for RPW8 function. RPW8 also functions in tobacco as a transgene to confer resistance to powdery mildew, indicating that the RPW8-signaling pathway is highly conserved. To understand how RPW8 originated, we have recently conducted an evolutionary analysis and found that the Arabidopsis RPW8... Complete Information... | Representative PublicationsXiao,S. (2006) Current perspectives on molecular mechanisms of plant disease resistance. In:Teixeira da Silva (ed.), "Floriculture, Ornamental and Plant Biotechnology: Advances and Topical Issues"(1st ed.) Global Science Books, UK. pp 317-333. Xiao, S., Calis O, Elaine Patrick, E., Zhang, Z., Charoenwattana, P., Muskett, P., Parker, J., Turner, J.G. (2005). The atypical Resistance gene, RPW8, recruits components of basal defence for powdery mildew resistance in Arabidopsis. Plant J 42, 95-110. Xiao, S., Emerson, B., Ratanasut, K., Patrick, E., O'Neill, C., Bancroft, I., and Turner, J. G. (2004). Origin and maintenance of a broad-spectrum disease resistance locus in Arabidopsis. Mol Biol Evol 21, 1661-1672 Complete Listing... |
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