UNIVERSITÄT ZU KÖLN

P04: The obligate biotrophic powdery mildew fungus - adaptation to the leaf epidermal cell niche by defending against other microbes.

The powdery mildew disease affects a wide range of plants. Mildew infections of cereals including barley and wheat as well as high-value fruit and vegetables such as tomato and grapes lead to significant yield losses. Previous and ongoing research on these fungi and their hosts aims to provide a thorough understanding of the molecular mechanisms underlying the disease and this will further contribute to employment of durable powdery mildew disease-resistance of host plants. It has recently become evident that inter-microbial interactions play an important role in shaping the pathogen resistance of a host plant. This also includes host mechanisms such as improved nutrient uptake, upregulation of the plant's immune system and the acquisition of systemic resistance. Adapted microbial phytopathogens must therefore not only have developed mechanisms to overcome the plant immune system, but also to disrupt the protective effect of the host microbiome and defend their host niche against other microbial inhabitants of the same host. The strict host specificity, the adaptation to proliferate on a highly specific host niche, the epidermal cell, and the obligate biotrophic lifestyle of the barley powdery mildew fungus Blumeria hordei (Bh) demonstrates that this ascomycete has successfully adapted to defend the epidermal cell layer and underlaying tissue against other microbes that may colonize the barley host. In this project, we will investigate the molecular strategies that the barley powdery mildew fungus Bh employs to cooperate and compete with other host-associated microbes to successfully colonize its host niche.

For more information visit Saur lab

Publications

Saur, I.M.L., Panstruga, R., and Schulze-Lefert, P. (2021). NOD-like receptor-mediated plant immunity: from structure to cell death. Nat Rev Immunol 21, 305–318. 10.1038/S41577-020-00473-Z.25. Märkle, H., Saur, I.M.L., and Stam, R. (2022). Evolution of resistance (R) gene specificity. EssaysBiochem 66, 551–560. 10.1042/EBC20210077.

Bauer, S., Yu, D., Lawson, A.W., Saur, I.M., Frantzeskakis, L., Kracher, B., Logemann, E., Chai, J., Maekawa, T., and Schulze-Lefert, P. (2021). The leucine-rich repeats in allelic barley MLA immune receptors define specificity towards sequence-unrelated powdery mildew avirulence effectors with a predicted common RNase-like fold. PLoS Pathog 17, e1009223. 10.1371/JOURNAL.PPAT.1009223

Saur, I.M.L., and Hückelhoven, R. (2021). Recognition and defence of plant-infecting fungal pathogens. J Plant Physiol 256, 153324. 10.1016/J.JPLPH.2020.153324

Saur, I.M.L., Bauer, S., Kracher, B., Lu, X., Franzeskakis, L., Muller, M.C., Sabelleck, B., Kummel, F., Panstruga, R., Maekawa, T., et al. (2019). Multiple pairs of allelic MLA immune receptor-powdery mildew AVRA effectors argue for a direct recognition mechanism. Elife 8, e44471. 10.7554/eLife.44471.

Lu, X.L., 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. Proceedings of the National Academy of Sciences USA 113, 6486–6495. 10.1073/pnas.1612947113.