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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Cereal Crops Improvement Research » Research » Publications at this Location » Publication #422036
Research Project: Host-Pathogen Interactions Affecting Wheat and Barley

Location: Cereal Crops Improvement Research

Title: Pyrenophora teres f. maculata, causal agent of spot form net blotch of barley, is an emerging pathogen of durum wheat

Author
item Wyatt, Nathan
item Skiba, Ryan
item Peters Haugrud, Amanda
item ZHANG, QIJUN - North Dakota State University
item SZABO-HEVER, AGNES - North Dakota State University
item Xu, Steven
item Faris, Justin
item Friesen, Timothy

Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/15/2025
Publication Date: 4/15/2025
Citation: Wyatt, N.A., Skiba, R.M., Peters Haugrud, A.R., Zhang, Q., Szabo-Hever, A., Xu, S.S., Faris, J.D., Friesen, T.L. 2025. Pyrenophora teres f. maculata, causal agent of spot form net blotch of barley, is an emerging pathogen of durum wheat. Phytopathology. https://doi.org/10.1094/PHYTO-01-25-0002-R.
DOI: https://doi.org/10.1094/PHYTO-01-25-0002-R

Interpretive Summary: Spot Form Net Blotch (SFNB), a destructive fungal foliar disease caused by Pyrenophora teres f. maculata, has long plagued barley crops worldwide. While this pathogen has not historically affected durum wheat in the United States, our recent research reveals a concerning development, showing that P. teres f. maculata can infect the most popular durum wheat cultivars in North Dakota, the number one durum producer in the US. To better understand this emerging threat, we employed genetic mapping and genome-wide association studies to show that a single major genetic locus on wheat chromosome 2A is responsible for susceptibility to this pathogen. This discovery underscores the need for US durum wheat breeders and growers to proactively address this new challenge. By understanding the genetic basis of susceptibility, we can develop more resistant cultivars and effective management strategies to safeguard future durum wheat production.

Technical Abstract: Emergent plant pathogens are a threat to global food security, as they evolve to infect new hosts and spread to new geographic regions. Pyrenophora teres f. maculata is a foliar pathogen of barley that is present worldwide and can cause significant yield losses. Recent reports indicated that P. teres f. maculata has made a host jump to wheat, a staple food crop that is responsible for a significant portion of global caloric intake. In this study, a tetraploid wheat panel comprised of local and global Triticum turgidum subspecies was screened with six P. teres f. maculata isolates and a range of resistant to moderately susceptible reaction types were observed. A recombinant inbred population, developed from a cross between the moderately susceptible durum cultivar Divide and the resistant cultivated emmer accession PI 272527, was inoculated with P. teres f. maculata isolates from the United States, Denmark, New Zealand, and Australia, and subsequent quantitative trait loci analysis was used to identify loci segregating for resistance and susceptibility. To identify associations with resistance and susceptibility in the broader durum wheat population, the P. teres f. maculata isolate FGOB10Ptm-1 was used to inoculate a representative subset of the Global Durum Panel, and a genome-wide association study was performed. Results of both host mapping studies indicated a major association with resistance or susceptibility to P. teres f. maculata on the short arm of durum wheat chromosome 2A with additional minor loci also being identified.