Variation of a transgenic strain of Beauveria bassiana during subculturing
一株球孢白僵菌转基因工程菌在继代培养中的变异

Genetic engineering is an effective approach for solving the problems of slow speed of killing insect by entomopathogenic fungi. However, it remains problematic whether the inserted gene can be lost and whether variation and degeneration can occur in the transgenic strains during subculturing as those happen frequently to the wild-type strains. In the present paper, the variation of Bb13T-10-3, a AaIT-transgenic strain of Beauveria bassiana during subculturing was studied. The results revealed that sectorization of Bb13T-10-3 could occur, suggesting that it varied like its mother strain Bb13, but the inserted gene was not lost. As compared to the sectorization rate of Bb13 and one of its single spore isolate Bb13-S, that of Bb13T-10-3 remained high, while sporulation and virulence obviously declined on the pine caterpillar, Dendrolimus punctatus. However, Bb13T-10-3-S, one of the single spore isolates from Bb13T-10-3 was relatively stable, with sporulation and virulence against pine caterpillars being much higher than those of Bb13 and Bb13-S.