Control of Lepidopteran insect pests in transgenic Chinese cabbage (Brassica rapa ssp pekinensis) transformed with a synthetic Bacillus thuringiensis cry1C gene

A synthetic Bacillus thuringiensis cryl C gene was transferred to three Korean cultivars of Chinese cabbage via Agrobacterium tumefaciens-mediated transformation of hypocotyl explants. Hygromycin resistance served as an efficient selective marker. The transformation efficiency ranged from 5% to 9%. Transformation was confirmed by Southern blot analysis, PCR, Northern analysis, and progeny tests. Many transgenic plants of the closed-head types (lines Olympic and Samjin) flowered in vitro. Over 50 hygro-mycin-resistant plants were successfully transferred to soil. The transgenic plants and their progeny were resistant to diamondback moths (DBM. Plutella xylo-stella), the major insect pest of crucifers world-wide, as well as to cabbage loopers (Trichoplusia ni) and imported cabbage worms (Pieris rapae). Both susceptible Geneva DBM and a DBM population resistant to CrylA protein were controlled by the CrylC-trans-genic plants. The efficient and reproducible transformation system described may be useful for the transfer of other agriculturally important genes into Chinese cabbage.