Correlated Expression of gfp and Bt cry1Ac Gene Facilitates Quantification of Transgenic Hybridization between Brassicas

Abstract

Gene flow from transgenic oilseed rape (BRASSICA NAPUS) might not be avoidable, thus, it is important to detect and quantify hybridization events with its relatives in real time. Data are presented showing the correlation between genetically linked green fluorescent protein (GFP) with BACILLUS THURINGIENSIS (Bt) CRY1AC gene expression in hybrids formed between transgenic B. NAPUS "Westar" and a wild Chinese accession of wild mustard (B. JUNCEA) and hybridization between transgenic B. NAPUS and a conspecific Chinese landrace oilseed rape. Hybrids were obtained either by spontaneous hybridization in the field or by hand-crossing in a greenhouse. In all cases, transgenic hybrids were selected by GFP fluorescence among seedlings originating from seeds harvested from B. JUNCEA and the Chinese oilseed rape plants. Transgenicity was confirmed by PCR detection of transgenes. GFP fluorescence was easily and rapidly detected in the hybrids under greenhouse and field conditions. Results showed that both GFP fluorescence and Bt protein synthesis decreased as either plant or leaf aged, and GFP fluorescence intensity was closely correlated with Bt protein concentration during the entire vegetative lifetime in hybrids. These findings allow the use of GFP fluorescence as an accurate tool to detect gene-flow in time in the field and to conveniently estimate BT CRY1AC expression in hybrids on-the-plant.

Fitness and maternal effects in hybrids formed between transgenic oilseed rape (Brassica napus L.) and wild brown mustard [B. juncea (L.) Czern et Coss.] in the field

“…The third generation of the progenies of transgenic event 1 was used in this study. F 1 hybrids were produced by pollinating ten wild brown mustard plants of that local seed collection with pollen from more than ten transgenic OSR (GT) plants in a greenhouse 36…”

“…Seedling emergence was recorded after removal of the agricultural film in the spring. At the beginning of April 2006, plants were culled to one plant per location following GFP fluorescence screening and transgene PCR analysis of F 1 hybrids 36. The result of this assay was the retention of transgenic F 1 hybrids and removal of non‐transgenic plants.…”

Dynamic expression of green fluorescent protein and Bacillus thuringiensis Cry1Ac endotaxin in interspecific hybrids and successive backcross generations (BC1 and BC2) between transgenic Brassica napus crop and wild Brassica juncea

“…Correlated expression of Bt cry1Ac and GFP transgenes is caused by the regulation of identical but independent CaMV 35S promoters with cassettes located linked on the same genomic locus (Harper et al , 1999; Halfhill et al , 2001). An early finding was reported for the correlated expression of the two genes at the vegetative growth stage (Shen et al , 2006). Here we reported again the correlation at reproductive stages.…”

“…The GFP gene cloned from the jellyfish ( Aequorea victoria ) is a useful in vivo real‐time marker for monitoring transgenes when coupled to another transgene (Stewart, 1996, 2005). The correlated expression of Bt and GFP genes in hybrid could facilitate the detection of hybridization in the field (Shen et al , 2006) and also relative gene expression of a second gene (Harper et al , 1999). In one study, Shen et al (2006) demonstrated a close correlation between Bt Cry1Ac protein and GFP fluorescence in hybrids formed between transgenic B. napus and wild B. juncea at vegetative growth stage but no such test has been yet conducted at the reproductive growth stage.…”

“…The correlated expression of Bt and GFP genes in hybrid could facilitate the detection of hybridization in the field (Shen et al , 2006) and also relative gene expression of a second gene (Harper et al , 1999). In one study, Shen et al (2006) demonstrated a close correlation between Bt Cry1Ac protein and GFP fluorescence in hybrids formed between transgenic B. napus and wild B. juncea at vegetative growth stage but no such test has been yet conducted at the reproductive growth stage. Different performance could exist between these two stages (Di et al , 2009).…”