How filamentous plant pathogen effectors are translocated to host cells

The interaction of microbes with “signature” plants is largely governed by secreted effector proteins, which serve to dampen plant defense responses and modulate host cell processes. Secreted effectors can function either in the apoplast or within plant cell compartments. How oomycetes and fungi translocate their effectors to plant cells is still poorly understood and controversial. While most oomycete effectors share a common ‘signature’ that was proposed to mediate their uptake via endocytosis, fungal effectors display no conserved motifs at the primary amino acid sequence level. Here we summarize current knowledge in the field of oomycete and fungal effector uptake and highlight emerging themes that may unite rather than set apart these unrelated filamentous pathogens.