coronatine

Coronatine is a phytotoxin produced by certain strains of *Pseudomonas syringae*, a bacterium commonly found in plants. It belongs to the family of coronafacients, which are compounds that induce abnormal growth patterns in host plants. The name "coronatine" derives from the crown gall-like symptoms it causes on infected plants, particularly in the leaves and stems.

This phytotoxin is structurally similar to jasmonic acid, a plant hormone involved in stress responses, wound healing, and defense mechanisms. Coronatine mimics jasmonic acid, leading to the activation of jasmonate signaling pathways in plants. This interference disrupts normal physiological processes, often resulting in stunted growth, chlorosis (yellowing of leaves), and abnormal tissue development. The toxin also suppresses salicylic acid-mediated defense responses, making plants more susceptible to further infection.

*Pseudomonas syringae* strains producing coronatine are often associated with diseases such as bacterial leaf blight in cereals, particularly wheat and barley. The toxin’s role in pathogenesis has been extensively studied, as it contributes to the bacterium’s ability to colonize and spread within host plants. Research has also explored coronatine’s potential as a model compound for understanding plant hormone signaling and its manipulation by pathogens.

Beyond its role in plant pathology, coronatine has been used as a research tool in plant biology to study jasmonate-dependent signaling. Its structural and functional similarities to natural plant hormones make it valuable for investigating how plants regulate growth and defense in response to biotic and abiotic stresses. Synthetic analogs of coronatine have also been developed for agricultural applications, though their use remains limited due to regulatory and environmental concerns.