title: A Bacterial Effector Co-opts Calmodulin to Target the Plant Microtubule Network.
abstract: The bacterial pathogen Pseudomonas syringae depends on effector proteins secreted by its type III secretion system for the pathogenesis of plants. The majority of these effector proteins are known suppressors of immunity, but their plant targets remain elusive. Using Arabidopsis thaliana as a model host, we report that the HopE1 effector uses the host calcium sensor, calmodulin (CaM), as a co-factor to target the microtubule-associated protein 65 (MAP65), an important component of the microtubule network. HopE1 interacted with MAP65 in a CaM-dependent manner, resulting in MAP65-GFP dissociation from microtubules. Transgenic Arabidopsis expressing HopE1 had reduced secretion of the immunity protein PR-1 compared to wild-type plants. Additionally, Arabidopsis map65-1 mutants were immune deficient and were more susceptible to P. syringae. Our results suggest a virulence strategy in which a pathogen effector is activated by host calmodulin to target MAP65 and the microtubule network, thereby inhibiting cell wall-based extracellular immunity.
authors.affiliation: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA; Department of Plant Pathology, University of Nebraska, Lincoln, NE 68588-0722, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Guo
authors.affiliation: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA; School of Biological Sciences, University of Nebraska, Lincoln, NE 68588-0118, USA.
authors.forename: Panya
authors.initials: P
authors.lastname: Kim
authors.affiliation: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA; Department of Plant Pathology, University of Nebraska, Lincoln, NE 68588-0722, USA.
authors.forename: Guangyong
authors.initials: G
authors.lastname: Li
authors.affiliation: Center for Biotechnology, University of Nebraska, Lincoln, NE 68588-0665, USA.
authors.forename: Christian G
authors.initials: CG
authors.lastname: Elowsky
authors.affiliation: Center for Plant Science Innovation, University of Nebraska, Lincoln, NE 68588-0660, USA; Department of Plant Pathology, University of Nebraska, Lincoln, NE 68588-0722, USA. Electronic address: jalfano2@unl.edu.
authors.forename: James R
authors.initials: JR
authors.lastname: Alfano
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D010935:Plant Diseases / Q000382:microbiology*; D044224:Pseudomonas syringae / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D001426:Bacterial Proteins; D002147:Calmodulin; D008869:Microtubule-Associated Proteins