Search

Oomycetes form a phylogenetically distinct group of eukaryotic microorganisms that include some of the most notorious pathogens of plants and animals. Through the deployment of a remarkably diverse array of effector proteins, oomycete pathogens succeed to overcome host defences and cause infection. Effectors can operate extracellularly or enter living cells where they target diverse subcellular compartments. Genome sequence information indicates that oomycetes express several hundred host-translocating effectors potentially targeting a myriad of host processes. To counteract, plants rely on a wide variety of extra- and intracellular immune receptors facilitating pattern-triggered and effector-triggered immunity, respectively. Similarly, effectors from animal pathogenic oomycetes also target host immune response pathways, which in turn causes the activation of the humoral and adaptive immune system. In this review, we compare plant and animal pathogenic oomycete effectors regarding their type, function, genetic diversity, as well as host responses.

Diseases caused by oomycete pathogens are a global threat to forestry, agriculture and aquaculture. Because of their complex life cycles, characterised by dormant resting structures that enable their survival for years under hostile environmental conditions, reducing the spread of oomycetes is a challenging task. In this review, we present an overview of this challenge, starting from the need to understand the natural and anthropogenic dispersal pathways of these pathogens. Focusing on the European Union, we explore current legislation that forms a backbone for biosecurity protocols against the spread of oomycetes through trade and transport. We discuss the options for prevention, containment and long-term management of oomycetes in different production settings, emphasising the importance of prevention as the most cost-efficient strategy to reduce the spread of these pathogens. Finally, we highlight some of the new and emerging technologies and strategies as potential tools in the integrated pest management of animal and plant diseases caused by oomycetes. We emphasise the urgency of actions to halt the global spread of these pathogens.