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

Abstract

The persistence and stability of a transgene encoding a Bacillus thuringiensis (Bt) Cry1Ac insecticidal protein was investigated in hybrids between crop Brassica napus and a recurrent wild Brassica juncea population. Interspecific hybrids (F 1 ) and backcross progenies (BC 1 , BC 2 ) containing green fluorescent protein (GFP) and Bt genes were successfully produced in the greenhouse. Stable Bt toxin levels were found in hybrid and advanced backcross progenies formed in wild B. juncea. Bt Cry1Ac concentration was significantly lower in BC 2 plants than in transgenic B. napus, F 1 , BC 1 , while no significant differences were detected among the latter three plant genotypes. A GFP marker gene was used as a scorable marker and indicator of Bt transgene expression. GFP fluorescence intensity was significantly correlated with Bt Cry1Ac concentration at the flowering stage and the pod formation stage in both transgenic oilseed rape hybrids and backcrossed progenies (BC 1 , BC 2 ). It was demonstrated that GFP was a suitable marker for Bt protein in the backcross of B. juncea, which could facilitate the detection of gene flow and is useful in biosafety management.

The effects of the presence of Bt-transgenic oilseed rape in wild mustard populations on the rhizosphere nematode and microbial communities

“…These soil samples were evenly mixed and transported back to the laboratory where nematodes were extracted. Microbial communities were assayed only for soil samples taken on July 4th because the Bt concentration was highest at this date when plants flowered (Lei et al, 2011). Soil characteristics, including pH, temperature and electrical conductivity, were measured using TRIME-PICO-IPH TDR (Germany).…”

Loss of C‐genome‐specific markers during transgene introgression from Brassica napus to wild Brassica juncea

“…Brassica napus L. (canola) is an outcrossing plant, and many of its closely‐related species occur naturally in the environment. Wild Brassica juncea (L.) Czernajew is a weedy species widely distributed in agricultural ecosystems (Lei et al ). Gene flow between B. napus and B. juncea do spontaneously occur in the field (Dong et al , Liu et al ).…”

“…Gene flow between B. napus and B. juncea do spontaneously occur in the field (Dong et al , Liu et al ). Although transgenic Brassica crop plants have not been commercially released, transgene flow research on transgenic B. napus and its wild relatives has become a model for the potential risk assessment of transgenic crops (Lei et al , Cao et al ). Much attention has been focused on the risk of gene flow from environmentally released transgenic B. napus (Liu et al , Busi and Powles ).…”

Relationship between hybridization frequency of <i>Brassica juncea</i> × <i>B. napus</i> and distance from pollen source (<i>B. napus</i>) to recipient (<i>B. juncea</i>) under field conditions in Japan

“…Although hybrids between weedy B. juncea and transgenic B. napus have not been reported in Japan ( J-BCH 2010 , MAFF 2010 ), there is some potential for their occurrence due to the high interspecific crossability between B. juncea and B. napus . However, compared with the relatively extensive research on hybridization and introgression between B. napus and B. rapa , there have been few reports on hybridization and introgression between B. napus and B. juncea ( Lei et al . 2011 ).…”