MoSDT1 triggers defense response through modulating phosphorylated proteins in rice

Area of Science:

• Plant Pathology
• Molecular Plant-Microbe Interactions
• Biochemistry

Background:

• Pathogen effector proteins can either infect hosts or trigger plant defense responses.
• The Magnaporthe oryzae effector MoSDT1 was previously found to activate rice defense when overexpressed.
• The precise mechanisms by which MoSDT1 influences rice resistance remain largely unknown.

Purpose of the Study:

• To elucidate the in vivo and in vitro mechanisms by which MoSDT1 influences rice resistance.
• To investigate the role of MoSDT1 in regulating plant defense pathways and protein phosphorylation.

Main Methods:

• Generation and analysis of MoSDT1-transgenic rice plants.
• In vitro studies using purified prokaryotic expression systems.
• Phosphoproteome analysis to identify modulated proteins.
• Analysis of defense-related gene expression, reactive oxygen species (ROS), and lignin content.

Main Results:

• MoSDT1 transgenic rice showed decreased ROS, increased lignin, and upregulated defense genes, including phenylalanine ammonia-lyase.
• In vitro, MoSDT1 induced ROS synthesis, callose deposition, PR gene expression, and SA/JA signaling.
• The zinc finger domain of MoSDT1 was identified as crucial for activating defense responses.
• Phosphoproteome analysis revealed MoSDT1 specifically upregulates phosphorylated proteins involved in stress response and growth.

Conclusions:

• MoSDT1 acts as a key inducer of rice defense responses, primarily by mediating changes in phosphorylated proteins.
• The effector enhances rice resistance through ROS synthesis, lignin accumulation, and modulation of defense-related genes and signaling pathways.
• MoSDT1's zinc finger domain is essential for its function in activating the plant's immune system.