Potential gene flow of two herbicide-tolerant transgenes from oilseed rape to wild B. juncea var. gracilis.
Four successive reciprocal backcrosses between F(1) (obtained from wild Brassica juncea as maternal plants and transgenic glyphosate- or glufosinate-tolerant oilseed rape, B. napus, as paternal plants) or subsequent herbicide-tolerant backcross progenies and wild B. juncea were achieved by hand pollination to assess potential transgene flow. The third and forth reciprocal backcrosses produced a number of seeds per silique similar to that of self-pollinated wild B. juncea, except in plants with glufosinate-tolerant backcross progeny used as maternal plants and wild B. juncea as paternal plants, which produced fewer seeds per silique than did self-pollinated wild B. juncea. Germination percentages of reciprocal backcross progenies were high and equivalent to those of wild B. juncea. The herbicide-tolerant first reciprocal backcross progenies produced fewer siliques per plant than did wild B. juncea, but the herbicide-tolerant second or third reciprocal backcross progenies did not differ from the wild B. juncea in siliques per plant. The herbicide-tolerant second and third reciprocal backcross progenies produced an amount of seeds per silique similar to that of wild B. juncea except for with the glufosinate-tolerant first and second backcross progeny used as maternal plants and wild B. juncea as paternal plants. In the presence of herbicide selection pressure, inheritance of the glyphosate-tolerant transgene was stable across the second and third backcross generation, whereas the glufosinate-tolerant transgene was maintained, despite a lack of stabilized introgression. The occurrence of fertile, transgenic weed-like plants after only three crosses (F(1), first backcross, second backcross) suggests a potential rapid spread of transgenes from oilseed rape into its wild relative wild B. juncea. Transgene flow from glyphosate-tolerant oilseed rape might be easier than that from glufosinate-tolerant oilseed rape to wild B. juncea. The original insertion site of the transgene could affect introgression.
Song
Xiaoling
X
Weed Research Laboratory, Nanjing Agricultural University, Nanjing, 210095, China.
Wang
Zhou
Z
Zuo
Jiao
J
Huangfu
Chaohe
C
Qiang
Sheng
S
D000613:Aminobutyrates / Q000494:pharmacology; D001483:Base Sequence; D001937:Brassica / Q000235:genetics*; D029741:Brassica rapa / Q000235:genetics*; D003433:Crosses, Genetic; D017931:DNA Primers / Q000235:genetics; D051456:Gene Flow; D017343:Genes, Plant; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006540:Herbicides / Q000494:pharmacology*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D019076:Transgenes; D000097797:Glyphosate
D000613:Aminobutyrates; D017931:DNA Primers; D005998:Glycine; D006540:Herbicides; D000097797:Glyphosate; C003121:phosphinothricin