Figure 2. N-terminal effector domains proposed to mediate host-cell entry.

Effectors from fungal (left) and oomycete (right) pathogens. Divergent oomycete and fungal effectors carry a general secretion signal peptide followed by non-conserved N-terminal regions called “uptake” or “targeting/translocation” domains that have been proposed to mediate host-cell entry. In oomycetes, small conserved amino acids motifs (e.g., RXLR, CHXC, or LFLAK) have been identified within these regions, which help to define effector families with many members.