Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis

Pseudomonas syringae pathovars expressing avrPto are avirulent on plants expressing the resistance gene Pto. Over 85 mutants of avrPto were generated with multiple strategies, and several assays were used to characterize AvrPto function. Only a core of 95 amino acids of the 164 residues was sufficie...

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Main Authors: Jeff H. Chang, Christian M. Tobias, Brian J. Staskawicz, Richard W. Michelmore
Format: Article
Language:English
Published: The American Phytopathological Society 2001-04-01
Series:Molecular Plant-Microbe Interactions
Online Access:https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.4.451
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author Jeff H. Chang
Christian M. Tobias
Brian J. Staskawicz
Richard W. Michelmore
author_facet Jeff H. Chang
Christian M. Tobias
Brian J. Staskawicz
Richard W. Michelmore
author_sort Jeff H. Chang
collection DOAJ
description Pseudomonas syringae pathovars expressing avrPto are avirulent on plants expressing the resistance gene Pto. Over 85 mutants of avrPto were generated with multiple strategies, and several assays were used to characterize AvrPto function. Only a core of 95 amino acids of the 164 residues was sufficient for binding Pto in the yeast two-hybrid system. Only nine of 65 mutant proteins of AvrPto with amino acid substitutions, created in planta and in vitro, did not interact with Pto in the Gal4 yeast two-hybrid system, suggesting that AvrPto can tolerate many nonconservative substitutions and still interact with Pto. These nine and 12 additional substitution mutants of AvrPto were characterized further. The ability to elicit a hypersensitive response and the effect on pathogenesis in planta for these 21 mutants of AvrPto were strongly correlated with recognition by Pto in the yeast two-hybrid system. Analyses of two proteins with substitutions H54P or D52G/L65P indicated that these residues may be required for delivery into the host cell and protein stability in the bacterial cytoplasm, respectively. The mutants that no longer interacted with Pto and had modified activities in planta were predicted to have changes in their secondary structure.
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spelling doaj.art-acc009202fe44b5f8dbea8744939529c2022-12-22T03:04:54ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062001-04-0114445145910.1094/MPMI.2001.14.4.451Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational AnalysisJeff H. ChangChristian M. TobiasBrian J. StaskawiczRichard W. MichelmorePseudomonas syringae pathovars expressing avrPto are avirulent on plants expressing the resistance gene Pto. Over 85 mutants of avrPto were generated with multiple strategies, and several assays were used to characterize AvrPto function. Only a core of 95 amino acids of the 164 residues was sufficient for binding Pto in the yeast two-hybrid system. Only nine of 65 mutant proteins of AvrPto with amino acid substitutions, created in planta and in vitro, did not interact with Pto in the Gal4 yeast two-hybrid system, suggesting that AvrPto can tolerate many nonconservative substitutions and still interact with Pto. These nine and 12 additional substitution mutants of AvrPto were characterized further. The ability to elicit a hypersensitive response and the effect on pathogenesis in planta for these 21 mutants of AvrPto were strongly correlated with recognition by Pto in the yeast two-hybrid system. Analyses of two proteins with substitutions H54P or D52G/L65P indicated that these residues may be required for delivery into the host cell and protein stability in the bacterial cytoplasm, respectively. The mutants that no longer interacted with Pto and had modified activities in planta were predicted to have changes in their secondary structure.https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.4.451
spellingShingle Jeff H. Chang
Christian M. Tobias
Brian J. Staskawicz
Richard W. Michelmore
Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
Molecular Plant-Microbe Interactions
title Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
title_full Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
title_fullStr Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
title_full_unstemmed Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
title_short Functional Studies of the Bacterial Avirulence Protein AvrPto by Mutational Analysis
title_sort functional studies of the bacterial avirulence protein avrpto by mutational analysis
url https://apsjournals.apsnet.org/doi/10.1094/MPMI.2001.14.4.451
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