A simplified method for screening ethylene-producing phytopathogenic fungi

Abstract

An easy and reliable method for measuring ethylene production is a prerequisite for research on fungal ethylene biosynthesis. In the present study, Botrytis cinerea was used as a model fungus to develop a method to detect in vitro production of ethylene. Spore suspensions were cultured in methionine-supplemented PDA. Small plates were excised from the medium and placed in a sealed ampoule bottle for the ethylene production assay. Gaseous samples were obtained from the sealed bottle for gas chromatography analysis. Using this method, eight species of phytopathogenic fungi (Alternaria alternate, Aspergillus niger, B. cinerea, Cladosporium sp., Fusarium oxysporum, Rhizopus stolonifer, Pestalotiopsis spp. and Penicillium spp.) were shown to produce significant levels of ethylene. Ethylene production by these fungi varied markedly during the seven day incubation period. In addition to the facilitation of fungal ethylene analyses, the present method allowed the observation of morphological characteristics of the test fungi during the assay. This spore-plate method is a simple, convenient, and broadly applicable method for assessing fungal ethylene production in vitro. This method may improve screening of fungi with high ethylene production rates, analysis of fungal growth and development, and be useful in crop protection.