Plant Effector-Triggered Immunity requires RNA Helicase PMH2-mediated Group II Intron Splicing in Mitochondria
Ying Yuan1,2,3, Xueya Li1,2,3, Siqi Tang1,2,3
1National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Plant Physiology
|June 9, 2026
Summary
PUTATIVE MITOCHONDRIAL RNA HELICASE 2 (PMH2) links RNA processing to plant immunity. PMH2 fine-tunes mitochondrial reactive oxygen species (ROS) bursts during effector-triggered immunity (ETI), enhancing plant defense against pathogens.
Area of Science:
- Plant Biology
- Molecular Plant Pathology
- Mitochondrial Genetics
Background:
- Reactive oxygen species (ROS) are critical signaling molecules in plant immunity against pathogens.
- Mitochondria are a primary source of ROS and are vital for plant defense.
- Efficient mitochondrial gene expression, dependent on RNA processing, is essential for plant immunity.
Purpose of the Study:
- To investigate the role of PUTATIVE MITOCHONDRIAL RNA HELICASE 2 (PMH2) in plant immunity.
- To elucidate the mechanism by which PMH2-mediated RNA splicing impacts mitochondrial function and plant defense.
- To understand the link between RNA helicases, mitochondrial ROS, and effector-triggered immunity (ETI).
Main Methods:
- Utilized Arabidopsis thaliana as a model organism.
- Investigated the effect of ETI activation on PMH2 function and cox2 splicing efficiency.
- Measured mitochondrial respiratory chain complex IV activity and mitochondrial ROS (mtROS) generation.
- Assessed the impact of mtROS on nuclear immune gene expression.
Main Results:
- ETI activation led to reduced splicing efficiency of the mitochondrial gene cox2, mediated by PMH2.
- This reduction in splicing decreased mitochondrial respiratory chain complex IV activity, promoting mtROS production.
- PMH2-mediated mtROS facilitated the expression of nuclear-encoded immune genes, bolstering plant defense.
- PMH2 was identified as a key regulator of mitochondrial RNA splicing impacting plant immunity.
Conclusions:
- PMH2 plays a significant role in effector-triggered immunity (ETI) by regulating mitochondrial RNA splicing.
- PMH2 fine-tunes mitochondrial ROS bursts through its control over cox2 splicing and complex IV activity.
- This mechanism highlights the crucial connection between RNA processing, mitochondrial dynamics, and robust plant immune responses.
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