Control of Lepidopteran insect pests in transgenic Chinese cabbage (Brassica rapa ssp pekinensis) transformed with a synthetic Bacillus thuringiensiscry1C gene

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