Immobilized Subpopulations of Leaf Epidermal Mitochondria Mediate PENETRATION2-Dependent Pathogen Entry Control in
Rene Fuchs1, Michaela Kopischke1, Christine Klapprodt1
1Department of Plant Cell Biology, Albrecht-von-Haller-Institute, Georg-August-University Göttingen, 37077 Göttingen, Germany The Sainsbury Laboratory, Norwich NR4 7UH, United Kingdom.
Abstract:
The atypical myrosinase PENETRATION2 (PEN2) is required for broad-spectrum invasion resistance to filamentous plant pathogens. Previous localization studies suggested PEN2-GFP association with peroxisomes. Here, we show that PEN2 is a tail-anchored protein with dual-membrane targeting to peroxisomes and mitochondria and that PEN2 has the capacity to form homo-oligomer complexes. We demonstrate pathogen-induced recruitment and immobilization of mitochondrial subpopulations at sites of attempted fungal invasion and show that mitochondrial arrest is accompanied by peripheral accumulation of GFP-tagged PEN2. PEN2 substrate production by the cytochrome P450 monooxygenase CYP81F2 is localized to the surface of the endoplasmic reticulum, which focally reorganizes close to the immobilized mitochondria. Exclusive targeting of PEN2 to the outer membrane of mitochondria complements the pen2 mutant phenotype, corroborating the functional importance of the mitochondrial PEN2 protein subpool for controlled local production of PEN2 hydrolysis products at subcellular plant-microbe interaction domains. Moreover, live-cell imaging shows that mitochondria arrested at these domains exhibit a pathogen-induced redox imbalance, which may lead to the production of intracellular signals.
Insights
PENETRATION2 (PEN2) protein targets both peroxisomes and mitochondria, crucial for plant defense against fungal pathogens. Immobilized mitochondria at invasion sites accumulate PEN2, signaling pathogen attack.
Area of Science:
- Plant pathology
- Cell biology
- Biochemistry
Background:
- PENETRATION2 (PEN2) is an atypical myrosinase vital for plant immunity against filamentous pathogens.
- Previous studies indicated PEN2-GFP localizes to peroxisomes, but its full targeting and function remained unclear.
Purpose of the Study:
- To elucidate the precise subcellular localization and functional role of PEN2 in plant defense.
- To investigate PEN2's interaction with other cellular components during pathogen invasion.
Main Methods:
- Utilized GFP-tagged PEN2 to track its localization in plant cells using live-cell imaging.
- Investigated PEN2's membrane targeting properties and homo-oligomerization capacity.
- Analyzed mitochondrial dynamics and PEN2 accumulation at pathogen attack sites.
Main Results:
- Demonstrated PEN2 is a tail-anchored protein with dual targeting to peroxisomes and mitochondria.
- Showcased pathogen-induced recruitment and immobilization of mitochondria at fungal invasion sites, with PEN2 accumulation.
- Confirmed that PEN2 targeting to the outer mitochondrial membrane rescues the pen2 mutant phenotype.
Conclusions:
- PEN2's dual localization and mitochondrial targeting are critical for its function in plant defense.
- Mitochondrial PEN2 facilitates localized production of defense compounds at pathogen interaction sites.
- Pathogen-induced mitochondrial dysfunction and redox imbalance may generate crucial defense signals.
Related Concept Videos
02:26Defenses Against Pathogens and Herbivores
02:22Introduction to Plant Diversity