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MoOrp-mediated PtdIns4P transportation is essential for autophagy and pathogenicity in Magnaporthe oryzae

Jian Wang1, Meng-Meng Chen2, Hai-Jiao Xu3

  • 1Department of Plant Pathology, MOA Key Lab of Pest Monitoring and Green Management, College of Plant Protection, China Agricultural University, Beijing, China.

Autophagy
|July 8, 2025
PubMed

Insights

Two oxysterol-binding protein-related proteins, MoOrp1 and MoOrp2, are crucial for Magnaporthe oryzae pathogenicity by transporting phosphatidylinositol-4-phosphate (PtdIns4P) to regulate autophagy, essential for fungal infection processes.

Area of Science:

  • Molecular Biology
  • Mycology
  • Cell Biology

Background:

  • Autophagy is critical for the pathogenicity of Magnaporthe oryzae.
  • Phosphatidylinositol-4-phosphate (PtdIns4P) is vital for autophagosome biogenesis and fusion.
  • The regulation of PtdIns4P on autophagic membranes remains unclear.

Purpose of the Study:

  • To investigate the role of oxysterol-binding protein-related proteins (MoOrp1 and MoOrp2) in M. oryzae autophagy and pathogenicity.
  • To elucidate the mechanism by which MoOrp1 and MoOrp2 regulate PtdIns4P levels on autophagic membranes.

Main Methods:

  • Gene knockout studies (simultaneous knockout of MoORP1 and MoORP2).
  • Autophagy flux assays.
  • Molecular analyses including PtdIns4P binding, MoAtg8 interaction, and bimolecular fluorescence complementation (BiFC).

Main Results:

  • Simultaneous deletion of MoORP1 and MoORP2 caused defects in autophagy-related infection processes, including lipid degradation, conidial autophagic cell death, appressorial turgor, and invasive hyphal growth.
  • The △Moorp1-2 strain showed impaired autophagosome formation and vacuolar fusion.
  • MoOrp1 and MoOrp2 bind PtdIns4P, are recruited to autophagosomes via MoAtg8 interaction, and their PtdIns4P-binding activity is essential for autophagy and pathogenicity.

Conclusions:

  • MoOrp1 and MoOrp2 function as PtdIns4P transporters, regulating autophagy in M. oryzae.
  • This study reveals novel roles for Atg8 protein and highlights the importance of MoOrp-mediated PtdIns4P translocation in fungal pathogenicity.
Keywords:
Atg8Magnaporthe oryzaeautophagyoxysterol-binding protein-related proteinpathogenicityphosphatidylinositol-4-phosphate

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