Image Credit: Greg Fuerst, USDA-ARS, Corn Insects and Crop Genetics Research Unit, Ames, IA
Obligate fungal pathogens (e.g., mildews and rusts) are a major threat to cereal grain production worldwide (Savary et al. 2012). Because they are unable to survive autonomously, obligate parasites are ideal tools to explore interdependent signaling between disease agents and their hosts. The powdery mildew fungus, Blumeria graminis, is an obligate biotrophic pathogen of cereals and has significant impact on food security (Dean et al. 2012). B. graminis f. sp. hordei (Bgh) is the causal agent of powdery mildew on barley (Hordeum vulgare L.).
Bgh isolate 5874 was obtained from Dr. J. Helms Jørgensen at the Risø National Laboratory, Roskilde, Denmark. It is avirulent on barley plants that encode the MLA1, MLA3, MLA6, or MLA12 nucleotide-binding leucine-rich repeat receptors (NLRs; Moscou et al. 2011). The reference genome for Bgh isolate 5874 will contribute to ongoing studies into how pathogen effectors (Lu et al. 2016, Ridout et al. 2006, Saur et al. 2019) influence plant immunity (Meng et al. 2009, Meng and Wise 2012, Moscou et al. 2011, Surana et al. 2017, Xu et al. 2015, Xu et al. 2014) and advance the application of that knowledge to benefit sustainable agriculture.
References:
- Dean, R., van Kan, J.A.L., Pretorius, Z.A., Hammond-Kosack, K.E., Di Pietro, A., Spanu, P.D., Rudd, J.J., Dickman, M., Kahmann, R., Ellis, J. and Foster, G.D. (2012) The top 10 fungal pathogens in molecular plant pathology. Molecular Plant Pathology, 13.
- Lu, X., Kracher, B., Saur, I.M.L., Bauer, S., Ellwood, S.R., Wise, R., Yaeno, T., Maekawa, T. and Schulze-Lefert, P. (2016) Allelic barley MLA immune receptors recognize sequence-unrelated avirulence effectors of the powdery mildew pathogen. Proc Natl Acad Sci USA, 113, E6486–E6495.
- Meng, Y., Moscou, M.J. and Wise, R.P. (2009) Blufensin1 negatively impacts basal defense in response to barley powdery mildew. Plant Physiol, 149, 271-285.
- Meng, Y. and Wise, R.P. (2012) HvWRKY10, HvWRKY19, and HvWRKY28 regulate Mla-triggered immunity and basal defense to barley powdery mildew. Mol Plant-Microbe Interact, 25, 1492-1505.
- Moscou, M.J., Lauter, N., Caldo, R.A., Nettleton, D. and Wise, R.P. (2011) Quantitative and temporal definition of the Mla transcriptional regulon during barley-powdery mildew interactions. Mol Plant-Microbe Interact, 24, 694-705.
- Ridout, C.J., Skamnioti, P., Porritt, O., Sacristan, S., Jones, J.D.G. and Brown, J.K.M. (2006) Multiple avirulence paralogues in cereal powdery mildew fungi may contribute to parasite fitness and defeat of plant resistance. The Plant Cell, 18, 2402-2414.
- Saur, I.M.L., Bauer, S., Kracher, B., Lu, X., Franzeskakis, L., Müller, M.C., Sabelleck, B., Kümmel, F., Panstruga, R., Maekawa, T. and Schulze-Lefert, P. (2019) Multiple pairs of allelic MLA immune receptor-powdery mildew AVRA effectors argue for a direct recognition mechanism. Elife, 8, e44471.
- Savary, S., Ficke, A., Aubertot, J.-N. and Hollier, C. (2012) Crop losses due to diseases and their implications for global food production losses and food security. Food Security, 4, 519-537.
- Surana, P., Xu, R., Fuerst, G., Chapman, A.V.E., Nettleton, D. and Wise, R.P. (2017) Interchromosomal transfer of immune regulation during infection of barley with the powdery mildew pathogen. G3: Genes|Genomes|Genetics, 7, 3317-3329.
- Xu, W., Meng, Y., Surana, P., Fuerst, G., Nettleton, D. and Wise, R.P. (2015) The knottin-like Blufensin family regulates genes involved in nuclear import and the secretory pathway in barley-powdery mildew interactions. Frontiers in Plant Science, 6, 409.
- Xu, W., Meng, Y. and Wise, R.P. (2014) Mla- and Rom1-mediated control of microRNA398 and chloroplast copper/zinc superoxide dismutase regulates cell death in response to the barley powdery mildew fungus. New Phytologist, 201, 1396-1412.
