Mitochondrial and peroxisomal Lon proteases are functionally divergent in environmental adaptation and pathobiology of the entomopathogenic fungus Beauveria bassiana

Lon protease belongs to the AAA‑ATPase family and plays comprehensive physiological roles via maintaining cellular protein homeostasis. This study seeks to explore the functions of Lon protease in biocontrol potential of the filamentous entomopathogenic fungus Beauveria bassiana. B. bassiana contained mitochondrial and peroxisomal Lon proteases (BbLon1 and BbLon2) which were functionally analyzed via gene disruption and complementation. BbLon1 contributed to fungal tolerance to oxidative, thermal, hyperosmotic, and cell wall-perturbing stresses as well as iron deficiency. Both BbLon1 and BbLon2 co-functioned in conidiation, but BbLon2 had a significant role in the hydrophobicity of conidia and mycelia. BbLon1 played more important roles in pathobiology than BbLon2, including penetration through the cuticle, immune evasion, in vivo development, extracellular acidification and mycosis. Current findings indicate that mitochondrial Lon proteinase plays more predominant roles in lifecycle of B. bassiana than peroxisomal one. This study provides in-depth knowledge for organellar functionality essential for biocontrol efficacy of the entomopathogenic fungi.