The possible mechanisms of copper resistance in the pathogen Pseudomonas syringae pathovars in stone fruit trees

Husseini A., Akköprü A.

Phytoparasitica, vol.49, pp.684-698, 2020 (SCI-Expanded)

  • Publication Type: Article / Article
  • Volume: 49
  • Publication Date: 2020
  • Doi Number: 10.1007/s12600-020-00828-1
  • Journal Name: Phytoparasitica
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Agricultural & Environmental Science Database, BIOSIS, CAB Abstracts, Veterinary Science Database
  • Page Numbers: pp.684-698
  • Van Yüzüncü Yıl University Affiliated: Yes


One of the most common diseases affecting Stone-fruits is Bacterial Canker, caused by Pseudomonas syringae pv. syringae (Pss) and morsprunorum (Psm). In this study, Pss and Psm were isolated from stone-fruit trees from the Western Aegean region (WA) and Lake Van Basin (LVB) of Turkey, where pesticide usage is high and low, respectively. We aimed to determine copper resistance levels, the involved resistance mechanisms and the reactions to copper pesticides of these isolates. The minimum inhibitory concentration (MIC) and lethal dose 50 (LD50) of the isolates were detected using CuSO4 and other Cu-pesticides. To determine the mechanisms of copper resistance, the presence of copA and cusA genes was investigated. The modified Fe/Cu Blue-CAS Agar media were used to investigate the relationship between the isolates’ copper resistance and each isolate’s ability to produce siderophores. The highest MIC value was 2 mM in CuSO4. The tolerance levels of the isolates from the WA and LVB regions were 29% and 47% susceptible, 29% and 47% low resistance and 42% and 6% resistant, respectively. The most successful pesticide was (CuSO4 + Ca (OH)2) + mancozeb. While none of the isolates had the cusA gene, four isolates had the copAgene, which was proven to be plasmid-borne. Differences between copA gene sequences were detected and were determined to be not related to the pathovars. The amount of siderophore produced against copper in Ps pathovars affected seems to be related with the resistance level. Also, Ps pathovars were able to tolerate copper at doses as high as 1.1 mM by producing siderophores, and at doses of 1.7 mM and above through the copA gene.