Further Investigation on Ethylene Production in Sweet Potato Root Tissue Infected by Ceratocystis fimbriata

Abstract

Regarding vigorous production of ethylene in sweet potato root tissue when infected by black rot fungus, Ceratocystis fimbriata, the contribution of ethylene production by the fungus itself in diseased tissue was investigated, with four kinds of experiments. It is concluded that the ratio of the production by the fungus itself to the total production in diseased tissue was really small and the ethylene synthetic pathway of the fungus involved L-methionine (Met), but not 1-aminocyclopropane-1-carboxylic acid (ACC). One of the pathways of ethylene production induced in diseased tissue was the Met-ACC pathway, which was also found in pectinase-treated tissue. It seems likely, however, that in the boundary part between infected and non-infected parts, some other pathway was also induced in response to the fungal infection, and this assumption was also supported in the case of pectinase treatment. The above results may be useful to understand the mechanism on ethylene production in stored vegetables and fruits when infected by pathogens.