High level resistance to Turnip mosaic virus in Chinese cabbage (Brassica campestris ssp pekinensis (Lour) Olsson) transformed with the antisense NIb gene using marker-free Agrobacterium tumefaciens infiltration

A TuMV-Nlb gene fragment was amplified from the total RNA of Chinese cabbage leaves infected with TuMV-C-4 by RT-PCR. This fragment was cloned into the marker-free plant binary vector pROK (a derivative of pROK2) in the antisense orientation and transformed into Chinese cabbage [Brassica canipestris ssp. pekinensis (Lour) Olsson] by the Agrobacterium tutnefaciens strain LBA4404 using infiltration genetransformation system. Forty-three transgenic T-0 plants were obtained. PCR, ELISA and Southern blot analysis showed that the TuMV-Nlb gene had integrated into the genome of Chinese cabbage and the heredity of this gene in some lines followed the 3:1 ratio. Both TO and T, transgenic plants showed high levels of resistance to TuMV when artificially inoculated with TuMV. RT-PCR analysis of To transgenic Chinese cabbage revealed the integrated TuMV-Nlb gene can be expressed normally. The infiltration gene-transformation system had proved effective in transformation of Chinese cabbage. (c) 2007 Elsevier Ireland Ltd. All rights reserved.