@article{kloppe_whetten_kim_powell_lück_douchkov_whetten_hulse‐kemp_balint‐kurti_cowger_2023, title={Two pathogen loci determine <i>Blumeria graminis}, volume={238}, ISSN={0028-646X 1469-8137}, url={http://dx.doi.org/10.1111/nph.18809}, DOI={10.1111/nph.18809}, abstractNote={Summary


Blumeria graminis f. sp. tritici (Bgt) is a globally important fungal pathogen of wheat that can rapidly evolve to defeat wheat powdery mildew (Pm) resistance genes. Despite periodic regional deployment of the Pm1a resistance gene in US wheat production, Bgt strains that overcome Pm1a have been notably nonpersistent in the United States, while on other continents, they are more widely established.

A genome‐wide association study (GWAS) was conducted to map sequence variants associated with Pm1a virulence in 216 Bgt isolates from six countries, including the United States. A virulence variant apparently unique to Bgt isolates from the United States was detected in the previously mapped gene AvrPm1a (BgtE‐5612) on Bgt chromosome 6; an in vitro growth assay suggested no fitness reduction associated with this variant.

A gene on Bgt chromosome 8, Bgt‐51526, was shown to function as a second determinant of Pm1a virulence, and despite < 30% amino acid identity, BGT‐51526 and BGTE‐5612 were predicted to share > 85% of their secondary structure. A co‐expression study in Nicotiana benthamiana showed that BGTE‐5612 and BGT‐51526 each produce a PM1A‐dependent hypersensitive response.

More than one member of a B. graminis effector family can be recognized by a single wheat immune receptor, and a two‐gene model is necessary to explain virulence to Pm1a.

}, number={4}, journal={New Phytologist}, publisher={Wiley}, author={Kloppe, Tim and Whetten, Rebecca B. and Kim, Saet‐Byul and Powell, Oliver R. and Lück, Stefanie and Douchkov, Dimitar and Whetten, Ross W. and Hulse‐Kemp, Amanda M. and Balint‐Kurti, Peter and Cowger, Christina}, year={2023}, month={Mar}, pages={1546–1561} }
 @article{kloppe_boshoff_pretorius_lesch_akin_morgounov_shamanin_kuhnem_murphy_cowger_2022, title={Virulence of Blumeria graminis f. sp. tritici in Brazil, South Africa, Turkey, Russia, and Australia}, volume={13}, ISSN={["1664-462X"]}, DOI={10.3389/fpls.2022.954958}, abstractNote={The globally distributed causal agent of powdery mildew on wheat, Blumeria graminis f. sp. tritici (Bgt), is one of the most rapidly adapting plant pathogens and requires monitoring for shifts in virulence to wheat resistance (Pm) genes. Virulence frequencies were assessed in a total of 346 Bgt isolates from several countries that had either lately recorded increasing powdery mildew epidemics (Brazil, South Africa, and Australia) or not recently been surveyed (Turkey and Russia). The results were compared to previously published surveys of United States and Egyptian Bgt (390 isolates). Many of the Pm genes that have potentially been employed longer (Pm1a–Pm17) were shown to have lost effectiveness, and the complexity of virulence to those genes was higher among Brazilian isolates than those from any other country. Some cases of high virulence frequency could be linked to specific Pm gene deployments, such as the widespread planting of cultivar Wyalkatchem (Pm1a) in Australia. Virulence was also assessed to a set of Pm genes recently introgressed from diploid and tetraploid wheat relatives into a hexaploid winter wheat background and not yet commercially deployed. The isolate collections from Fertile Crescent countries (Egypt and Turkey) stood out for their generally moderate frequencies of virulence to both the older and newer Pm genes, consistent with that region’s status as the center of origin for both host and pathogen. It appeared that the recently introgressed Pm genes could be the useful sources of resistance in wheat breeding for other surveyed regions.}, journal={FRONTIERS IN PLANT SCIENCE}, author={Kloppe, Tim and Boshoff, Willem and Pretorius, Zacharias and Lesch, Driecus and Akin, Beyhan and Morgounov, Alexey and Shamanin, Vladimir and Kuhnem, Paulo and Murphy, Paul and Cowger, Christina}, year={2022}, month={Aug} }