Breaking dependence on melanisation imparts diversity to a dogmatic invasion strategy of phytopathogenic fungi.

Colletotrichum and Pyricularia are destructive fungal phytopathogens that typically invade plants by forming a heavily melanised, unicellular infection structure known as an appressorium, enabling melanised appressorium-mediated entry (MAE). Appressorial melanisation is essential for invasion by these phytopathogens. Here, we report Colletotrichum fungi that can invade plants via nonmelanised appressorium-mediated entry (NMAE). Multifaceted analyses revealed interspecific variation in the degree of melanisation dependence across appressorial functions. NMAE-type appressoria accomplished these functions regardless of melanisation, thus being capable of early invasion. Comprehensive screening identified a monophyletic NMAE-type Colletotrichum group with rapid expansion. Critically, we identified an eccentric NMAE-type strain with erratic appressorial melanisation. We also rediscovered appressorium-independent hyphal tip-based entry (HTE)-type strains. Collectively, these findings establish a key paradigm for the plant infection strategy of Colletotrichum fungi. In contrast to the widely accepted view based on the MAE of Colletotrichum, this study suggests that appressorial melanisation is not universally required, underscoring the need to consider the emergence of NMAE- and HTE-type pathogens.