1. N - glycosylation shields Phytophthora sojae apoplastic effector PsXEG1 from a specific host aspartic protease.
- Author
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Xia Y, Ma Z, Qiu M, Guo B, Zhang Q, Jiang H, Zhang B, Lin Y, Xuan M, Sun L, Shu H, Xiao J, Ye W, Wang Y, Wang Y, Dong S, Tyler BM, and Wang Y
- Subjects
- Aspartic Acid Endopeptidases genetics, Cellulase genetics, Disease Resistance genetics, Gene Knockdown Techniques, Glycosylation, Host-Pathogen Interactions genetics, Phytophthora metabolism, Plant Proteins genetics, Plants, Genetically Modified, Protein Binding, Protein Processing, Post-Translational, Proteolysis, Glycine max enzymology, Glycine max genetics, Virulence, Aspartic Acid Endopeptidases metabolism, Cellulase metabolism, Phytophthora pathogenicity, Plant Diseases microbiology, Plant Proteins metabolism, Glycine max microbiology
- Abstract
Hosts and pathogens are engaged in a continuous evolutionary struggle for physiological dominance. A major site of this struggle is the apoplast. In Phytophthora sojae -soybean interactions, PsXEG1, a pathogen-secreted apoplastic endoglucanase, is a key focal point of this struggle, and the subject of two layers of host defense and pathogen counterdefense. Here, we show that N-glycosylation of PsXEG1 represents an additional layer of this coevolutionary struggle, protecting PsXEG1 against a host apoplastic aspartic protease, GmAP5, that specifically targets PsXEG1. This posttranslational modification also attenuated binding by the previously described host inhibitor, GmGIP1. N-glycosylation of PsXEG1 at N174 and N190 inhibited binding and degradation by GmAP5 and was essential for PsXEG1 's full virulence contribution, except in GmAP5-silenced soybeans. Silencing of GmAP5 reduced soybean resistance against WT P. sojae but not against PsXEG1 deletion strains of P. sojae. The crucial role of N-glycosylation within the three layers of defense and counterdefense centered on PsXEG1 highlight the critical importance of this conserved apoplastic effector and its posttranslational modification in Phytophthora -host coevolutionary conflict., Competing Interests: The authors declare no competing interest., (Copyright © 2020 the Author(s). Published by PNAS.)
- Published
- 2020
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