Abstract: OBJECTIVE： To study the genotoxicity of Agrobacterium pusense in order to provide scientific basis and data support for further toxicological research and application in the field of food industry. METHODS： The bacterial reversion mutation test (Ames test) was conducted using TA97a，TA98，TA100，TA102 and TA1535 strains，with five dose groups of 0.008，0.04，0.2，1 and 5 μL/plate，solvent control group (distilled water)，untreated control group，dimethyl sulfoxide control group (DMSO) and positive control group were also set up. The standard plate incorporation method was used in the study in the presence or absence of S₉ metabolic activation system with 3 parallel plates in each group and repeated once. In mammalian erythrocyte micronucleus test，KM mice were randomly divided into 5 groups according to male and female，with 5 animals per sex in each group. Three dose groups were set up as 2 500，5 000 and 10 000 mg/kg，and negative control group and positive control group (CP，40 mL/kg) were also set up. Chinese hamster lung cells (CHL) were used in chromosome aberration test in vitro，and the chromosome aberration test was performed in 1.25，2.50 and 5.00 μg/mL dose groups，respectively，as well as in negative control group (distilled water) and positive control group (+S₉，15 μg/mL CP；-S₉，0.20 μg/mL MMC). The test was conducted in the presence or absence of S₉ metabolic activation system. RESULTS： In the Ames test，the test article was not toxic. In the presence or absence of S₉，the average number of recurrent colonies in each dose group was less than 2 times that of the negative control group，indicating that the tested article did not induce the increase of reverted colony number，and the average number of recurrent colonies in the positive control group was 2 times higher than that in negative control group. In the micronucleus test of mammalian erythrocytes，the average rates of micronucleated cells in female KM mice in the 3 dose groups were 2.0‰，2.1‰ and 2.4‰，respectively，which had no statistical significance compared with the negative control group (1.8‰) (P>0.05). The average rates of micronucleus containing cells in male KM mice in the 3 dose groups were 2.0‰，2.3‰ and 2.5‰，respectively，which had no statistical significance compared with the negative control group (1.9‰) (P>0.05). While the positive control group cyclophosphamide significantly increased (P<0.01)；In vitro chromosome aberration test of mammalian cells，the total chromosome aberration rates of the 3 dose groups were 2%，3% and 6% with S₉，respectively，which was no significantly different compared with the negative control group (2%) (P>0.05). The total chromosome aberration rates of the 3 dose groups were 2%，3% and 5% without S₉，respectively. Compared with negative control group (2%)，there was no statistical significance (P>0.05)，while the positive control group was significantly increased (P<0.01). CONCLUSION： In the conditions of this study，Agrobacterium pusense was not genotoxic.

Key words: Agrobacterium pusense, Ames test, micronuclear test, chromosomal aberration test, genotoxicity