Production Profile and Comparison Analysis of Main Toxin Components of Fusarium Oxysporum F. Sp. Sesami Isolates with Different Pathogenicity Levels

Fusarium wilt is a common fungal disease in sesame caused by Fusarium oxysporum f.sp.sesami(FOS).To determine the toxin production profiles of the FOS isolates with different pathogenicity levels under various culture conditions,we assessed the content variation of fusaric acid(FA)and 9,10-dehydrofusaric acid(9,10-DFA)produced by the four representative FOS isolates.Results indicated that the concentration of FA reached to a maximum of 2848.66 μg/mL in Czapek medium,while 9,10-DFA was mainly produced in Richard and Low-carbon Richard medium.The concentration of 9,10-DFA on Richard culture medium varied from 0 μg/mL to 716.89 μg/mL.Of the five culture media used in this study,Czapek culture medium was the most conductive to produce FA.FA production was significantly affected by culture medium,culture time,and their interactions.Results suggest that there is no correlation between toxin production and pathogenicity level of FOS isolates.These findings provide key information for the mechanism analysis of FOS-sesame interaction and pathogen control.