From lichens to crops: Pathogenic potential ofPseudomonas syringaefromPeltigeralichens is similar to world-wide epidemic strains

Abstract

AbstractThe presence of bacteria belonging to thePseudomonas syringaecomplex (P. syringae) in the natural vegetation of several Icelandic habitat types has been recently reported, raising questions about the risk to Icelandic crops, particularly given the expected increase in agricultural activity due to climate warming. This study takes advantage of Iceland’s unique characteristics and the discovery ofP. syringaeinPeltigeralichens to gain a better understanding of the potential risk posed by this newly discovered ecological niche. The main objective is to evaluate the pathogenic potential and fitness in crops ofP. syringaestrains isolated fromPeltigeralichen sampled in Iceland, focusing on strains that belong to phylogroups 1 and 2, which commonly contain epidemic strains. The results indicate thatP. syringaeisolated from IcelandicPeltigeralichen demonstrate comparable fitness to well-known epidemic strains in eight out of the ten plant species tested, and certain strains exhibit similar pathogenicity in the three plant species analyzed. These findings provide valuable insights into the potential risks posed byP. syringaefrom Icelandic natural habitats and illustrate how strains from these habitats have a wide pathogenic potential to crops without having encountered these crops in the last several thousand years of their presence in Iceland.