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Retromer Regulates Macro- and Micro-Autophagy via Distinct Vacuolar Proteases in the Rice Blast Fungus

Summary

Rice blast disease causes significant crop damage worldwide. This research reveals how a cellular transport system called the retromer complex helps the fungus Magnaporthe oryzae develop and infect plants by delivering cleaning enzymes to the fungal cell’s digestive compartment. By understanding how these enzymes are transported and used, scientists have identified potential targets for developing better ways to control and prevent rice blast disease.

Background

The retromer complex sorts cargos from endosomes to prevent unnecessary vacuolar degradation, but its role in regulating vacuolar proteolytic systems during autophagy remains unclear. This study investigates how the retromer complex regulates both general and selective autophagy through delivery of vacuolar proteases in the rice blast fungus Magnaporthe oryzae.

Objective

To demonstrate that the retromer complex regulates macro- and micro-autophagy by ensuring delivery of vacuolar proteases MoPrb1 and MoPep4 into the vacuole lumen, and to elucidate the mechanisms of their transport and roles in fungal development and pathogenicity.

Results

MoVps35 transports the serine protease MoPrb1 from endosomes to the vacuole lumen, and deletion of retromer components prevents MoPrb1 transport. MoPrb1 is essential for autophagy-dependent conidiation and plant infection. MoVps35 indirectly interacts with aspartyl protease MoPep4 via MoPrb1, which is critical for pexophagy but dispensable for pathogenicity.

Conclusion

The retromer complex plays a crucial role in regulating both macro- and micro-autophagy through different vacuolar proteases in M. oryzae, with MoPrb1 essential for general autophagy and fungal pathogenicity, while MoPep4 is specifically required for selective autophagy of peroxisomes.
  • Published in:Advanced Science,
  • Study Type:Experimental Research,
  • Source: PMID: 40842061, DOI: 10.1002/advs.202510068
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