Initial host invasion of Colletotrichum gloeosporioides is dampened by 1-methylcyclopropene due to blocking ethylene sensitivity of the fungus

Abstract

Ethylene (ET) is not only a fruit ripening hormone, but also plays important roles in plant-pathogen interactions, as it is involved in both plant defense and fungal virulence. 1-methylcyclopropene (1-MCP) is a competitive inhibitor for ET being applied as a postharvest preservation agent to delay fruit ripening. Plant pathogenic fungi can also sense ET to promote fungal conidial germination, appressorium development, and pathogenicity. However, it is unclear whether 1-MCP could regulate postharvest disease development by interfering with the ET-sensing in pathogenic fungi. In this study, we identified the effects of ET and 1-MCP on the growth and development of Colletotrichum gloeosporioides, a fungal pathogen that causes anthracnose disease in various crops, and explored the regulatory effects of 1-MCP on the pathogenic fungus during its host invasions. The results showed that 1-MCP can inhibit the ET responses of C. gloeosporioides, including the ET-induced conidial germination, appressorium formation, and expression of the ethylene-responsive marker gene. Further analysis revealed that 1-MCP treatment dampened the host invasion of the fungus, and thus decreased disease severity on lime and strawberry fruit. Collectively, this study reveals the action mode of 1-MCP in inhibiting the fungal ET sensitivity and highlights the unexplored potential of using 1-MCP as a postharvest treatment to control postharvest diseases caused by fungal pathogens.