Characterization of the Barley Net Blotch Pathosystem at the Center of Origin of Host and Pathogen
Department of vegetables and field crops, Institute of Plant Science, Agricultural Research Organization, The Volcani Center, Rishon LeZion 7505101, Israel
The Mina & Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
Institute for Cereal Crops Improvement, Tel Aviv University, Tel Aviv 6997801, Israel
Federal Research Institute for Cultivated Plants, Institute for Resistance Research and Stress Tolerance, Julius Kühn-Institut (JKI), Erwin-Baur-Str. 27, 06484 Quedlinburg, Germany
Authors to whom correspondence should be addressed.
Pathogens 2019, 8(4), 275; https://doi.org/10.3390/pathogens8040275
Received: 6 November 2019 / Revised: 23 November 2019 / Accepted: 27 November 2019 / Published: 29 November 2019
(This article belongs to the Special Issue Genomics, Molecular, Genetics, and Diversity of Plant Disease Resistance)
Net blotch (NB) is a major disease of barley caused by the fungus Pyrenophora teres f. teres (Ptt), and P. teres f. maculata (Ptm). Ptt and Ptm infect the cultivated crop (Hordeum vulgare) and its wild relatives (H. vulgare ssp. spontaneum and H. murinum ssp. glaucum). The main goal of this research was to study the NB-causing pathogen in the crop center of origin. To address this, we have constructed a Ptt (n = 15) and Ptm (n = 12) collection isolated from three barley species across Israel. Isolates were characterized genetically and phenotypically. Aggressiveness of the isolates was determined based on necrotrophic growth rate on detached leaves of barley. In addition, isolates were genetically characterized by the mating type, followed by phylogenetic analysis, clustering them into seven groups. The analysis showed no significant differentiation of isolates based on either geographic origin, host of origin or form (Ptt vs. Ptm). Nevertheless, there was a significant difference in aggressiveness among the isolates regardless of host species, geographic location or sampling site. Moreover, it was apparent that the isolates derived from wild hosts were more variable in their necrotrophic growth rate, compared to isolates sampled from cultivated hosts, thereby suggesting that NB plays a major role in epidemiology at the center of barley origin where most of the diversity lies. Ptm has significantly higher necrotrophic and saprotrophic growth rates than Ptt, and for both a significant negative correlation was found between light intensity exposure and growth rates.