Pathogen manipulation of chloroplast function triggers a light-dependent immune recognition.
Chuyun Gao1, Huawei Xu1, Jie Huang1
1College of Plant Protection, Nanjing Agricultural University, 210095 Nanjing, China.
Summary
Plant immune sensors (NLRs) require light to detect pathogens. Light controls the production of a chloroplast protein (GLYK) essential for NLR activation by pathogen effectors.
Area of Science:
- Plant immunity
- Molecular plant-pathogen interactions
- Chloroplast biology
Background:
- Nucleotide-binding leucine-rich repeat (NLR) proteins act as intracellular immune sensors in plants and animals.
- Environmental factors, including light, are known to modulate NLR-mediated immunity, but the specific mechanisms are unclear.
- The Irish potato famine pathogen *Phytophthora infestans* utilizes effector proteins to suppress plant defenses.
Purpose of the Study:
- To investigate the role of light in NLR-mediated disease resistance.
- To elucidate the mechanism by which the NLR Rpi-vnt1.1 recognizes the *Phytophthora infestans* effector AVRvnt1.
- To understand how environmental factors influence plant immune responses.
Main Methods:
- Investigated the light-dependent activation of the NLR Rpi-vnt1.1 in *Arabidopsis thaliana*.
- Identified glycerate 3-kinase (GLYK) as a crucial co-factor for Rpi-vnt1.1 function.
- Analyzed the interaction between the effector AVRvnt1 and GLYK isoforms using biochemical and genetic approaches.
- Studied the regulation of GLYK gene expression by light-dependent alternative promoter selection.
Main Results:
- The NLR Rpi-vnt1.1 requires light to confer resistance against *Phytophthora infestans* strains expressing AVRvnt1.
- Activation of Rpi-vnt1.1 depends on the chloroplast protein GLYK, which is targeted by the pathogen effector AVRvnt1.
- Light regulates the production of full-length GLYK, essential for AVRvnt1 binding and Rpi-vnt1.1 activation; in darkness, a shorter GLYK isoform is produced, evading recognition.
- Pathogen effectors can manipulate chloroplast functions, leading to light-dependent plant immune responses.
Conclusions:
- Plant immune responses mediated by NLRs can be intricately regulated by light.
- Pathogen effectors target host chloroplast proteins to modulate plant immunity.
- Understanding light-dependent immune signaling is crucial for developing disease-resistant crops.
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