Molecular detection of Pyrenophora teres f. teres in barley: Optimizing RT-PCR for early infection monitoring

Barley net blotch disease caused by Pyrenophora teres f. teres causes significant yield losses in barley varieties in the world and in Türkiye. In this study, infected plant samples collected from various regions of Türkiye were characterized using morphological and molecular methods, and the most aggressive isolate was identified. Subsequently, 92 barley varieties cultivated in Türkiye were evaluated using this isolate, and their resistance levels were classified based on disease severity. A SYBR Green I-based RT-PCR method was optimized using the PttQ4-F/PttQ4-R primer pair specific to P. teres f. teres. This method enabled the quantitative monitoring of pathogen DNA in infected plant tissues and successfully detected pathogen DNA at concentrations as low as 0,001 ng. Analyses conducted on the 1st, 2nd, 3rd and 4th days post-infection revealed statistically significant differences between resistant and susceptible varieties. Findings from the study allowed the ranking of barley varieties based on their resistance levels, identifying Harman and Tokak 157/37 as resistant varieties and İnce 04 and Novasadski as susceptible varieties. In conclusion, the RT-PCR method was shown to be a powerful tool for the rapid and accurate early detection of the net blotch pathogen. The study contributed to the identification of resistant barley varieties and the development of effective disease management strategies, supporting sustainable barley production.