Abstract Detail

Ecological Section

Cao, Di [1], Stewart, Neal [2], Zheng, Min [3], Guan, Zhengjun [4], Wei, Wei [5], Tang, Zhixi [3], Ma, Keping [6].

Bacillus thuringiensis transgene introgression from Brassica napus to wild mustard B. juncea.

Introgression of transgenes from transgenic crops to weedy of wild relative species could influence the genetic background and ecological performance of the non-crop host. Wild Brassica juncea is a common weed in agricultural fields in China. Transgenic Brassica napus with an added insect resistance trait from a Bt Cry1Ac protein and a green fluorescent protein (GFP) marker gene was used in hybridization experiments with wild B. juncea. Hybrid F1 and successive five backcross generations were obtained using wild B. juncea as the maternal parent wherein transgenes were introgressed. The pod-set frequency on backcrossed B. juncea plants was over 66%, which suggested relatively high crossing compatibility ability between the hybrids and wild species. The seed number per pod and the pod-set rate in BC1 was the least of all generations tested, and then increased at the BC2 generation for which the thousand-seed weight was the highest of all generations. Seed size in backcrossed generations eventually approaches that of the wild parent. The plants in all backcrossed generations were consistent with the expected 1:1 segregation ratio of the transgenes. The Bt Cry1Ac protein concentrations in all genotypes at bolting and flowering stages was higher than those in the 4-5-leaf and pod-formation stages. Nonetheless, the Bt toxin in the fifth backcrossing generation (BC5) was of sufficient quantity to kill both polyphagous (Helicoverpa armigera) and oligophagous (Plutella xylostella) Lepidoptera. The non-transgenic plants of each generation did not control insects. As a consequence, the subsequent generations harboring the transgene from F1 to BC5 could have selection advantage against insect pests. It is suggested that transgene introgression could occur and result in selective advantages, which is useful in understanding gene flow from transgenic crops and the followed transgene introgression into wild.

1 - Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, , Beijing, China
2 - University of Tennessee, Department of Plant Sciences, Knoxville, USA
3 - Institute of Botany, Chinese Academy of Sciences
4 - Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan, Beijing, 100093, China
5 - 20 Nanxincun, Xiangshan, Beijing, N/A, 100093, China
6 - Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Xiangshan,

Keywords:
gene flow
insect bioassay
introgression
ecological consequence.

Presentation Type: Oral Paper:Papers for Sections
Session: 10
Location: Firs South/Boise Centre
Date: Monday, July 28th, 2014
Time: 3:00 PM
Number: 10007
Abstract ID:357
Candidate for Awards:None