This article is part of the supplement: The PAMGO Consortium: Unifying Themes In Microbe–Host Associations Identified Through The Gene Ontology

Open Access Highly Accessed Open Badges Review

Common and contrasting themes in host cell-targeted effectors from bacterial, fungal, oomycete and nematode plant symbionts described using the Gene Ontology

Trudy Torto-Alalibo1, Candace W Collmer23, Magdalen Lindeberg3, David Bird4, Alan Collmer3 and Brett M Tyler1*

Author Affiliations

1 Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA

2 Department of Biological and Chemical Sciences, Wells College, Aurora, NY 13026, USA

3 Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, USA

4 Center for the Biology of Nematode Parasitism, North Carolina State University, Raleigh, NC 27695, USA

For all author emails, please log on.

BMC Microbiology 2009, 9(Suppl 1):S3  doi:10.1186/1471-2180-9-S1-S3

Published: 19 February 2009


A wide diversity of plant-associated symbionts, including microbes, produce proteins that can enter host cells, or are injected into host cells in order to modify the physiology of the host to promote colonization. These molecules, termed effectors, commonly target the host defense signaling pathways in order to suppress the defense response. Others target the gene expression machinery or trigger specific modifications to host morphology or physiology that promote the nutrition and proliferation of the symbiont. When recognized by the host's surveillance machinery, which includes cognate resistance (R) gene products, defense responses are engaged to restrict pathogen proliferation. Effectors from diverse symbionts may be delivered into plant cells via varied mechanisms, including whole organism cellular entry (viruses, some bacteria and fungi), type III and IV secretion (in bacteria), physical injection (nematodes and insects) and protein translocation signal sequences (oomycetes and fungi). This mini-review will summarize both similarities and differences in effectors and effector delivery systems found in diverse plant-associated symbionts as well as how these are described with Plant-Associated Microbe Gene Ontology (PAMGO) terms.