MoMtg1 Acts as a Novel Transcriptional Repressor of MoSwi6 During Appressorium-Mediated Penetration in the Rice Blast...

Area of Science:

• Plant Pathology
• Molecular Mycology
• Cell Biology

Background:

• Appressoria are crucial for plant pathogenic fungi like Magnaporthe oryzae to infect hosts.
• Cell cycle control is vital for appressorium function, but its regulatory mechanisms are not fully understood.

Purpose of the Study:

• To identify novel regulators of cell cycle control during appressorium development in M. oryzae.
• To elucidate the molecular mechanisms underlying MoMtg1's role in appressorium function and pathogenicity.
• To explore potential strategies for controlling rice blast disease.

Main Methods:

• Identification and characterization of the conserved protein MoMtg1.
• Analysis of gene deletion mutants (∆Momtg1, ∆Moswi6) and overexpression studies (MoCYC1).
• Investigation of appressorium development, melanization, turgor, ROS accumulation, and septin assembly.
• Host-induced gene silencing and small molecule inhibition assays.

Main Results:

• MoMtg1 acts as a transcriptional repressor, interacting with MoSwi6 to regulate cell cycle progression.
• Mutants lacking MoMtg1 or MoSwi6 exhibit defects in appressorium development, including impaired melanization, turgor, ROS, and septin assembly.
• MoMtg1 negatively regulates, while MoSwi6 positively regulates, the expression of the essential cyclin gene MoCYC1.
• Silencing MoMTG1 in plants conferred resistance to M. oryzae, and a MoMtg1-inhibitor reduced fungal infection.

Conclusions:

• MoMtg1 is a novel transcriptional repressor critical for cell cycle regulation during M. oryzae appressorium development.
• The MoMtg1-MoSwi6-MoCYC1 pathway is essential for appressorium function and pathogenicity.
• Targeting MoMtg1 presents a promising strategy for developing novel disease control measures against rice blast.