SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein
The Mla (Mildew resistance locus a) of barley (Hordeum vulgare L.) is an effective model for cereal immunity against fungal pathogens. Like many resistance proteins, variants of the MLA coiled-coil nucleotide-binding leucine-rich repeat (CC-NLR) receptor often require the HRS complex (HSP90, RAR1, a...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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The American Phytopathological Society
2022-03-01
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| Series: | Molecular Plant-Microbe Interactions |
| Subjects: | |
| Online Access: | https://apsjournals.apsnet.org/doi/10.1094/MPMI-08-21-0217-R |
| _version_ | 1811261230546944000 |
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| author | Antony V. E. Chapman J. Mitch Elmore Maxwell McReynolds Justin W. Walley Roger P. Wise |
| author_facet | Antony V. E. Chapman J. Mitch Elmore Maxwell McReynolds Justin W. Walley Roger P. Wise |
| author_sort | Antony V. E. Chapman |
| collection | DOAJ |
| description | The Mla (Mildew resistance locus a) of barley (Hordeum vulgare L.) is an effective model for cereal immunity against fungal pathogens. Like many resistance proteins, variants of the MLA coiled-coil nucleotide-binding leucine-rich repeat (CC-NLR) receptor often require the HRS complex (HSP90, RAR1, and SGT1) to function. However, functional analysis of Sgt1 has been particularly difficult, as deletions are often lethal. Recently, we identified rar3 (required for Mla6 resistance 3), an in-frame Sgt1ΔKL308-309 mutation in the SGT1-specific domain, that alters resistance conferred by MLA but without lethality. Here, we use autoactive MLA6 and recombinant yeast-two-hybrid strains with stably integrated HvRar1 and HvHsp90 to determine that this mutation weakens but does not entirely disrupt the interaction between SGT1 and MLA. This causes a concomitant reduction in MLA6 protein accumulation below the apparent threshold required for effective resistance. The ΔKL308-309 deletion had a lesser effect on intramolecular interactions than alanine or arginine substitutions, and MLA variants that display diminished interactions with SGT1 appear to be disproportionately affected by the SGT1ΔKL308-309 mutation. We hypothesize that those dimeric plant CC-NLRs that appear unaffected by Sgt1 silencing are those with the strongest intermolecular interactions with it. Combining our data with recent work in CC-NLRs, we propose a cyclical model of the MLA-HRS resistosome interactions.[Graphic: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2022. |
| first_indexed | 2024-04-12T18:59:32Z |
| format | Article |
| id | doaj.art-3eeb1da94b8545048963a5f08ccf8fe7 |
| institution | Directory Open Access Journal |
| issn | 0894-0282 1943-7706 |
| language | English |
| last_indexed | 2024-04-12T18:59:32Z |
| publishDate | 2022-03-01 |
| publisher | The American Phytopathological Society |
| record_format | Article |
| series | Molecular Plant-Microbe Interactions |
| spelling | doaj.art-3eeb1da94b8545048963a5f08ccf8fe72022-12-22T03:20:12ZengThe American Phytopathological SocietyMolecular Plant-Microbe Interactions0894-02821943-77062022-03-0135327428910.1094/MPMI-08-21-0217-RSGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR ProteinAntony V. E. Chapman0J. Mitch Elmore1Maxwell McReynolds2Justin W. Walley3Roger P. Wise4Interdepartmental Genetics & Genomics, Iowa State University, Ames, IA 50011, U.S.A.Department of Plant Pathology & Microbiology, Iowa State University, Ames, IA 50011, U.S.A.Department of Plant Pathology & Microbiology, Iowa State University, Ames, IA 50011, U.S.A.Interdepartmental Genetics & Genomics, Iowa State University, Ames, IA 50011, U.S.A.Interdepartmental Genetics & Genomics, Iowa State University, Ames, IA 50011, U.S.A.The Mla (Mildew resistance locus a) of barley (Hordeum vulgare L.) is an effective model for cereal immunity against fungal pathogens. Like many resistance proteins, variants of the MLA coiled-coil nucleotide-binding leucine-rich repeat (CC-NLR) receptor often require the HRS complex (HSP90, RAR1, and SGT1) to function. However, functional analysis of Sgt1 has been particularly difficult, as deletions are often lethal. Recently, we identified rar3 (required for Mla6 resistance 3), an in-frame Sgt1ΔKL308-309 mutation in the SGT1-specific domain, that alters resistance conferred by MLA but without lethality. Here, we use autoactive MLA6 and recombinant yeast-two-hybrid strains with stably integrated HvRar1 and HvHsp90 to determine that this mutation weakens but does not entirely disrupt the interaction between SGT1 and MLA. This causes a concomitant reduction in MLA6 protein accumulation below the apparent threshold required for effective resistance. The ΔKL308-309 deletion had a lesser effect on intramolecular interactions than alanine or arginine substitutions, and MLA variants that display diminished interactions with SGT1 appear to be disproportionately affected by the SGT1ΔKL308-309 mutation. We hypothesize that those dimeric plant CC-NLRs that appear unaffected by Sgt1 silencing are those with the strongest intermolecular interactions with it. Combining our data with recent work in CC-NLRs, we propose a cyclical model of the MLA-HRS resistosome interactions.[Graphic: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2022.https://apsjournals.apsnet.org/doi/10.1094/MPMI-08-21-0217-RBlumeria graminis f. sp. hordeichaperonenucleotide-binding leucine-rich repeat (NLR) receptorpowdery mildew |
| spellingShingle | Antony V. E. Chapman J. Mitch Elmore Maxwell McReynolds Justin W. Walley Roger P. Wise SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein Molecular Plant-Microbe Interactions Blumeria graminis f. sp. hordei chaperone nucleotide-binding leucine-rich repeat (NLR) receptor powdery mildew |
| title | SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein |
| title_full | SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein |
| title_fullStr | SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein |
| title_full_unstemmed | SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein |
| title_short | SGT1-Specific Domain Mutations Impair Interactions with the Barley MLA6 Immune Receptor in Association with Loss of NLR Protein |
| title_sort | sgt1 specific domain mutations impair interactions with the barley mla6 immune receptor in association with loss of nlr protein |
| topic | Blumeria graminis f. sp. hordei chaperone nucleotide-binding leucine-rich repeat (NLR) receptor powdery mildew |
| url | https://apsjournals.apsnet.org/doi/10.1094/MPMI-08-21-0217-R |
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