title: Stable Bacillus thuringiensis transgene introgression from Brassica napus to wild mustard B. juncea.
abstract: Transgenic canola (Brassica napus) with a Bacillus thuringiensis cry1Ac gene and a green fluorescent protein (GFP) marker gene was used in hybridization experiments with wild Brassica juncea. Hybrid F1 and successive five backcross generations were obtained. The pod-set frequency on backcrossed B. juncea plants was over 66%, which suggested relatively high crossing compatibility between the hybrids and wild species. The seed setting 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 approached 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 at bolting and flowering stages was higher compared to the 4-5-leaf and pod-formation stages. Nonetheless, the Bt toxin in the fifth backcrossing generation (BC5) was sufficient to kill both polyphagous (Helicoverpa armigera) and oligophagous (Plutella xylostella) Lepidoptera. As a consequence, the subsequent generations harboring the transgene from F1 to BC5 could have selection advantage against insect pests. The result is useful in understanding gene flow from transgenic crops and the followed transgene introgression into wild.
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Di
authors.initials: D
authors.lastname: Cao
authors.affiliation: Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA.
authors.forename: C Neal
authors.initials: CN
authors.lastname: Stewart
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Min
authors.initials: M
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Zhengjun
authors.initials: Z
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Zhi-Xi
authors.initials: ZX
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China. Electronic address: weiwei@ibcas.ac.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.affiliation: State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Beijing 100093, China.
authors.forename: Ke-Ping
authors.initials: KP
authors.lastname: Ma
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D029688:Brassica napus / Q000235:genetics*; D018556:Crops, Agricultural / Q000235:genetics; D003433:Crosses, Genetic; D004731:Endotoxins / Q000235:genetics*; D051456:Gene Flow; D005798:Genes, Bacterial; D049452:Green Fluorescent Proteins / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics*; D060434:Herbivory; D006824:Hybridization, Genetic; D009036:Moths; D009149:Mustard Plant / Q000235:genetics*; D063245:Plant Development; D018515:Plant Leaves; D030821:Plants, Genetically Modified / Q000235:genetics*; D012639:Seeds; D019076:Transgenes
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D049452:Green Fluorescent Proteins
keywords: Brassica napus; Bt Cry1Ac protein; Gene flow; Insect bioassay; Introgression; Segregation ratio