In molecular biology, elicitins are a family of small, highly conserved proteins secreted by phytopathogenic microorganisms belonging to the Phytophthora and Pythium species.

[1] They are toxic proteins responsible for inducing a necrotic and systemic hypersensitive response in plants from the Solanaceae and Cruciferae families.

Leaf necrosis provides immediate control of fungal invasion and induces systemic acquired resistance; both responses mediate basic protection against subsequent pathogen inoculation.

Members of this family share a high level of sequence similarity, but they differ in net charge, dividing them into two classes: alpha and beta.

[2] Phenotypically, the two classes can be distinguished by their necrotic properties: beta-elicitins are 100-fold more toxic and provide better subsequent protection.