The phytotoxin coronatine is a multifunctional component of the virulence armament of Pseudomonas syringae.

Xueqing Geng,Mikiko Shimada,David Mackey,Lin Jin,Min Gab Kim

doi:10.1007/s00425-014-2151-x

Xueqing Geng, Mikiko Shimada + Show 3 more

Open Access

https://doi.org/10.1007/s00425-014-2151-x

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Abstract

Plant pathogens deploy an array of virulence factors to suppress host defense and promote pathogenicity. Numerous strains of Pseudomonas syringae produce the phytotoxin coronatine (COR). A major aspect of COR function is its ability to mimic a bioactive jasmonic acid (JA) conjugate and thus target the JA-receptor COR-insensitive 1 (COI1). Biological activities of COR include stimulation of JA-signaling and consequent suppression of SA-dependent defense through antagonistic crosstalk, antagonism of stomatal closure to allow bacterial entry into the interior of plant leaves, contribution to chlorotic symptoms in infected plants, and suppression of plant cell wall defense through perturbation of secondary metabolism. Here, we review the virulence function of COR, including updates on these established activities as well as more recent findings revealing COI1-independent activity of COR and shedding light on cooperative or redundant defense suppression between COR and type III effector proteins.

Highlights

Phytotoxins are microbe-produced secondary metabolites that interfere with and sometimes kill plant cells
The key roles of hormone signaling and secondary metabolic pathways in the ability of plants to deal with these stresses make targeting of them an effective strategy deployed by plant bacterial pathogens to suppress host defense
We speculated about targeting of ET-signaling by COR and considered how one, or perhaps both, of these activities contributes to the various virulence activities of COR

Summary

Introduction

Phytotoxins are microbe-produced secondary metabolites that interfere with and sometimes kill plant cells. Other effects of phytotoxins are quite diverse and include perturbation of metabolism of lipids, sugars, and cell walls, synthesis of proteins and nucleic acids, membrane integrity and mitosis (Duke and Dayan 2011; Ferguson and Johnston 1980; Goudet et al 1999; Pruess et al 1973; Hoffman 1995; King and Calhoun 2009; Strobel et al 1996; Thuleau et al 1988; Walton 2006; Daub et al 2005; Tanaka 1996).

References production

Conclusions and future questions