Expression of a Cytochrome P450 Gene from Bermuda Grass <i>Cynodon dactylon</i> in Soybean Confers Tolerance to Multiple Herbicides

Bermuda grass (Cynodon dactylon) is notoriously difficult to control with some commonly used herbicides. We cloned a cytochrome P450 gene from Bermuda grass, named P450-N-Z1, which was found to confer tolerance to multiple herbicides in transgenic Arabidopsis. These herbicides include: (1) acetolactate synthase (ALS) inhibitor herbicides nicosulfuron and penoxsulam; (2) p-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibiting herbicide mesotrione; (3) synthetic auxin herbicide dicamba; (4) photosynthesis inhibitor bentazon. We further generated transgenic soybean plants expressing P450-N-Z1, and found that these transgenic soybean plants gained robust tolerance to nicosulfuron, flazasulfuron, and 2,4-dichlorophenoxyacetic acid (2,4-D) in greenhouse assays. A field trial demonstrated that transgenic soybean is tolerant to flazasulfuron and 2,4-D at 4-fold and 2-fold the recommended rates, respectively. Furthermore, we also demonstrated that flazasulfuron and dicamba are much more rapidly degraded in vivo in the transgenic soybean than in non-transgenic soybean. Therefore, P450-N-Z1 may be utilized for engineering transgenic crops for herbicide tolerance