Abstract:

The pathogen causing sesame charcoal rot were collected, isolated, purified and identified (including phenotype analysis, molecular characterization and pathogenicity identification in the sprouting stage), and the Macrophomina phaseolina with strong pathogenicity was obtained in this study. Then the M. phaseolina pathogencity was evaluated in the inoculated tissues of mature plants with infecting toothpick pieces. In sesame stems, M. phaseolina caused brown-black necrotic streaks along vascular tissues, and then the streaks began to shrink radioactively and undergo local necrosis. Finally, M. phaseolina caused extensive necrosis. Sclerotium can also be found in the stems inoculated with pathogenic bacteria. All isolates of M. phaseolina were isolated from the inoculated stems and grown in pure culture again. These results fulfilled Koch’s postulates for M. phaseolina as a pathogen of mature sesame in China. These findings lay an important foundation for sesame resistance research.