Amino acid substitution in the coat protein of Melon necrotic spot virus causes loss of binding to the surface of Olpidium bornovanus zoospores

摘要

Melon necrotic spot virus (MNSV) is transmitted by the fungus Olpidium bornovanus. In this study, we used immunofluorescence microscopy to detect MNSV particles over the entire surface of the O. bornovanus zoospore; MNSV particles were not detected onthe related fungus O. virulentus, which cannot transmit MNSV. The amino acid substitution Ile-> Phe at position 300 in the MNSV coat protein resulted in loss of both specific binding and fungal transmission, while virion assembly and biological aspectswere unaffected. Taken together, these results suggest that the MNSV coat protein acts as a ligand to the O. bornovanus zoospore as part of a fungal-vector transmission system.