Plants have a variety of mechanisms they use to defend themselves against pathogens and pests. These defenses can sometimes be manipulated genetically to develop resistant crop varieties, an economical and environmentally friendly way to control disease. Pathogenic organisms are constantly evolving, however, and typically become virulent on these resistant varieties. An understanding of how resistance and virulence evolves in natural and managed populations helps us determine which types of resistances will remain effective for a useful period.
Bacteria and fungi secrete proteins to help them utilize their substrates and some plant pathogens secrete these directly into plant cells. The roles of most of these effector proteins are to overcome plant defenses. These are also detected by plant resistance gene products that have roles in pathogen recognition. One of our research programs is using a genomics approach to identify and characterize effector proteins from the stripe rust fungus, an important pathogen that affects wheat worldwide. Characterization of these effector proteins is a key to understanding the basic mechanisms of pathogenicity in these biotrophic fungi. We hope this will indicate why some cereals, like rice, are not attacked by rust fungi while most other cereals are. Ultimately, we would like to utilize the defense mechanisms of rice in cereals like wheat.
Some cultivated species (e.g. wheat) have little variation in their resistance to certain important pathogens, so sources of genetic resistance are not available. We therefore try to find resistance in related species and try to transfer this resistance to the cultivated types. Another approach we are trying, for soil borne pathogens, is to identify genotypes or cultural conditions that favor microbes that are able to suppress the pathogenic microbes. We are using high throughput DNA pyrosequencing approaches to characterize microbial populations in soil and to identify the microbes that are most important.
E. M. Babiker, S. H. Hulbert, Paulitz T. C. (2012) Hyaloperonospora camelinae on Camelina sativa in Washington State: Detection, Seed Transmission, and Chemical Control. Plant Dis. 96:1670-1674.
Kincaid, R.L., K.A. Johnson, J.J. Michal, A.C. Huisman, S.H. Hulbert, and W.L. Pan. 2012. Case Study: Production of silage containing biennial canola and peas for use as forage in a dairy rotation. The Professional Animal Scientist 28:120-124.
Walsh,D.T., Babiker,E.M., Burke,I.C., Hulbert SH. (2012) Camelina Mutants Resistant to Acetolactate Synthase Inhibitor Herbicides. Molecular Breeding Molecular Breeding: Volume 30:1053-1063
Babiker, E., Hulbert, S. Schroeder, K., Paulitz, T. (2011) Optimum Timing of Pre-Plant Applications of Glyphosate to Manage Rhizoctonia Root Rot in Barley. Plant Disease 95: 304-310.
Bansal, R, Hulbert, SH, Schemerhorn, B, Reese, JC, Whitworth, RJ, Stuart, JJ, Chen, M-S (2011) Hessian fly-Associated Bacteria: Transmission, Essentiality, and Composition. PLoS ONE doi:10.1371/journal.pone.0023170
Dong, Y.-L. Yin, C., Hulbert, S.H., Chen, X., Kang, Z. (2011) Cloning and expression analysis of three secreted protein genes from wheat stripe rust fungus Puccinia striiformis f. sp. tritici. World J Microbiol Biotechnol 27:1261–1265
Jayaveeramuthu Nirmalaa, Tom Dradera, Paulraj K. Lawrence, Chuntao Yin, Scot Hulbert, Camille M. Steber, Brian J. Steffenson, Les J. Szabo, Diter von Wettstein, and Andris Kleinhofs (2011) Concerted action of two avirulent spore effectors activates Reaction to Puccinia graminis (Rpg1)-mediated cereal stem rust resistance. Proc. Natl. Acad. Sci. USA 108: 14676-14681
Kincaid, R., K. Johnson, J. Michal,S. Hulbert, W. Pan, J. Barbano, and A. Huisman. 2011. Biennial canola for forage and ecosystem improvement in dryland cropping systems. 2011. Advances in Animal Biosciences 2(2):457.
Rouse NN, Saleh AA, Seck A., Keeler KH, Travers SE, Hulbert SH and KA Garrett (2011) Genomic and resistance gene homolog diversity of the dominant tallgrass prairie species across theCentral U.S. precipitation gradient. PLoS ONE 6(4): e17641. doi:10.1371/journal.pone.0017641
Yin, C., Hulbert, S. (2011) Prospects for functional analysis of effectors from cereal rust fungi. Euphytica 179:57–67
Yin, C., Jurgenson, J.E., Hulbert, S. (2011) Development of a Host-induced RNAi System in the Wheat Stripe Rust Fungus Puccinia striiformis f. sp. tritici. Mol. Plant-Microbe Interact. 24: 554–561
Travers, S. E., Tang, Z. Caragea, D., Garrett, K.A., Hulbert, S. H., Leach, J. E., Bai , J., Saleh, A., Knapp, A.K., Fay, P.A., Nippert, J., Schnable P.S. and M.D. Smith (2010) Spatial and temporal changes in Andropogon gerardii transcription profiles in association with climate change. Journal of Ecology 98:374-383
Chen, M-S. Liu, X., Yang, Z., Zhao, H., Shukle, R.H., Stuart, J.J. and S. H. Hulbert (2010) Unusual conservation among genes encoding small secreted salivary gland proteins from a gall midge. BMC Evolutionary Biology; 10:296
Smith, S.M., Steinau, M., Trick, H.N. and Hulbert, S.H. (2010) Recombinant Rp1 genes confer necrotic or nonspecific resistance phenotypes. Mol. Genet Genomics 283:591–602
Yin, C., Jones, K.L., Peterson, D.E., Garrett, K.A., Hulbert, S.H., Paulitz T. C. (2010) Members of soil bacterial communities sensitive to tillage and crop rotation. Soil Biology and Biochemistry 42:2111-2118.
Chintamanani, S, Hulbert, S.H., Johal G.S., Balint-Kurti, P.J. (2010) Identification of a Maize Locus that Modulates the Hypersensitive Defense Response, Using Mutant-Assisted Gene Identification and Characterization (MAGIC) Genetics, 184(3):813-825