A fungal effector targets a heat shock-dynamin protein complex to modulate mitochondrial dynamics and reduce plant...

Area of Science:

• Plant pathology
• Mitochondrial biology
• Molecular plant-microbe interactions

Background:

• Mitochondria play a crucial role in plant immunity.
• Fungal pathogens employ effectors to suppress host defenses.
• Mitochondrial dynamics, including fission and fusion, are critical for cellular functions.

Purpose of the Study:

• To investigate the mechanism by which the fungal effector MoCDIP4 from Magnaporthe oryzae suppresses rice immunity.
• To elucidate the role of the mitochondria-associated protein complex OsDjA9-OsDRP1E in rice immunity.
• To understand how pathogen effectors manipulate host mitochondrial dynamics.

Main Methods:

• Yeast two-hybrid assays to identify protein interactions.
• Biochemical assays to study protein degradation.
• Genetic manipulation of rice (knockout and overexpression) to assess immune responses.
• Microscopy to observe mitochondrial morphology.

Main Results:

• The fungal effector MoCDIP4 targets the OsDjA9-OsDRP1E complex in rice.
• OsDjA9 interacts with OsDRP1E and promotes its degradation, regulating mitochondrial fission.
• MoCDIP4 binding to OsDjA9 prevents OsDRP1E degradation, leading to OsDRP1E accumulation, shortened mitochondria, and increased susceptibility to M. oryzae.
• Conversely, manipulating OsDjA9 and OsDRP1E levels affects mitochondrial length and rice resistance.

Conclusions:

• Magnaporthe oryzae utilizes the effector MoCDIP4 to disrupt rice immunity by targeting the HSP40-DRP complex (OsDjA9-OsDRP1E).
• This targeting perturbs mitochondrial dynamics, specifically inhibiting mitochondria-mediated plant immunity.
• The study reveals a novel pathogen strategy involving effector-mediated manipulation of host mitochondrial fission for immune suppression.