Abstract: Atrazine (2-chloro-4-ethylamino-6-isopropylamno-1,3,5-triazine) is a wildly used herbicide in the world for controlling broad-leaf weeds in corn and sugarcane. However, atrazine is degraded slowly in the environment with an average half-life ranging from 4 to 57 weeks, and has been detected in soil as well as in ground and surface water in several countries. Atrazine chlorohydrolase (AtzA) catalyses the hydrolytic dechlorination and detoxification of atrazine to hydroxyatrazine, a non-herbicidal and non-toxic substance and is more strongly sorbed to soil than atrazine. In the present paper, atzAs were amplified from pMD4 plasmid (containing atzA-ADP) and pET21b-atzA-NK plasmid (containing atzA-NK), and inserted into plant expression plasmid pBin438. The recombinant plasmid was successfully introduced into tobacco leaf disks by Agrobacterium-mediated transformation and 136 plantlets were regenerated from selected medium contained 20 mg L^-1 kanamycin and 150 μg mL^-1 atrazine, and then were subjected to analyses of PCR and RT-PCR. The PCR using primers atzA-7/atzA-2, atzA-5/atzA-8, and atzA-7/atzA-8, which are specific for atzA, revealed that 42 of 72 (58.3%) pBin438-atzA-ADP and 38 of 64 (59.4%) of pBin438-atzA-NK regenerated plants were transgenic, respectively. Further RT-PCR indicated that 38.1% (16 of 42) of atzA-ADP and 28.9% (11 of 38) of atzA-NK, expressed AtzA in transgenic tobacco plants, respectively. After 50 days’ growth on 1/2MS medium contained 150 mg L^-1 atrazine, the transgenic plants degraded a large amount of atrazine presented in the medium with degrading as high as 79.26% in line 401, whereas 0.47% in the wild type. These results indicated that the transgenic tobacco plants can catalyze atrazine effi-ciently.

Key words: Atrazine chlorohydrolase (AtzA), Transgenic, Agrobacterium-mediate transformation, Tobacco, Phytoremediation capability of atrazine