Characterization of Trichoderma polysporum from Spitsbergen, Svalbard archipelago, Norway, with species identity, pathogenicity to moss, and polygalacturonase activity

Six isolates of Trichoderma polysporum-like species isolated from a moss (Sanionia uncinata) in high arctic wetlands at Spitsbergen Island, Svalbard, Norway, were examined for species identification, effects of temperature on growth, pathogenicity to the moss, and polygalacturonase (PGase) activity. All isolates from Spitsbergen were identified as T. polysporum based on morphology, sequences of the rDNA-ITS regions, and growth response to temperature. In addition, two isolates of T. polysporum from Germany and Japan were used. All isolates from Spitsbergen, Germany and Japan infected epidermal tissues of the moss, but did not cause any symptoms in in vitro inoculation tests at 0 °C. One of the isolates from Spitsbergen and the German isolate showed high activity of PGase, an enzyme produced by many saprotrophic and pathogenic fungi, in a pectin liquid medium. The enzyme activity was evident for both isolates even at 0 °C. The present results document the presence of T. polysporum in the high arctic wetlands. The epidermal infection to the moss and PGase production at 0 °C of the T. polysporum isolates suggest that the species likely inhabits a niche as a saprotroph or an endophyte in the arctic environments.