Barley resistance and susceptibility to fungal cell entry involve the interplay of ROP signaling with phosphatidylinositol‐monophosphates
SUMMARY Rho‐of‐plant small GTPases (ROPs) are regulators of plant polar growth and of plant–pathogen interactions. The barley ROP, RACB, is involved in susceptibility toward infection by the barley powdery mildew fungus Blumeria hordei (Bh) but little is known about the cellular pathways that connec...
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| Veröffentlicht in: | The Plant journal : for cell and molecular biology Jg. 123; H. 2; S. e70356 - n/a |
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| Hauptverfasser: | , , , , , , , , , , |
| Format: | Journal Article |
| Sprache: | Englisch |
| Veröffentlicht: |
England
John Wiley and Sons Inc
01.07.2025
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| Schlagworte: | |
| ISSN: | 0960-7412, 1365-313X, 1365-313X |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | SUMMARY
Rho‐of‐plant small GTPases (ROPs) are regulators of plant polar growth and of plant–pathogen interactions. The barley ROP, RACB, is involved in susceptibility toward infection by the barley powdery mildew fungus Blumeria hordei (Bh) but little is known about the cellular pathways that connect RACB signaling to disease susceptibility. Here we identify novel RACB interaction partners of plant or fungal origin by untargeted co‐immunoprecipitation of constitutively active (CA) RACB tagged by green fluorescent protein from Bh‐infected barley epidermal layers and subsequent analysis by liquid chromatography‐coupled mass spectrometry. Three of the immunoprecipitated proteins, a plant phosphoinositide phosphatase, a plant phosphoinositide phospholipase, and a putative Bh‐effector protein, are involved in the barley‐Bh‐pathosystem and support disease resistance or susceptibility, respectively. RACB and its plant interactors bind to overlapping anionic phospholipid species in vitro, and in the case of RACB, this lipid interaction is mediated by its carboxy‐terminal polybasic region (PBR). Fluorescent markers for anionic phospholipids show altered subcellular distribution in barley cells during Bh attack and under expression of a RACB‐binding fungal effector. Phosphatidylinositol 4‐phosphate, phosphatidylinositol 3,5‐bisphosphate, and phosphatidylserine show a distinct enrichment at the haustorial neck region, suggesting a connection to subcellular targeting of RACB at this site. The interplay of ROPs with anionic phospholipids and phospholipid‐metabolizing enzymes may thus enable the subcellular enrichment of components pivotal for success or failure of fungal penetration.
Significance Statement
The ROP GTPase RACB has been co‐immunoprecipitated with two host phospholipid‐metabolizing enzymes and one fungal effector that influences pathogen interaction. All three modeled protein complexes share an overlapping binding interface with RACB.
Rho‐of‐plant small GTPases (ROPs) are regulators of plant cell polarity, disease resistance, and susceptibility to fungal invasion of plant cells. In cell development, ROPs act in concert with phosphoinositides, but such a function was not established for ROP signaling in plant–microbe interactions. Here we show relevant phosphoinositide interaction of barley RACB, a ROP GTPase acting in susceptibility to invasion by Blumeria hordei, and new interaction partners of RACB that influence fungal invasion success and may act on plant phosphoinositide metabolism. |
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| Bibliographie: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
| ISSN: | 0960-7412 1365-313X 1365-313X |
| DOI: | 10.1111/tpj.70356 |