An expressed napin storage protein gene from Brassica rapa, BcNA1, has been cloned and sequenced. The gene is a member of a family of four to seven napin genes in B. rapa and is highly expressed in developing seeds. An expression cassette containing the DNA flanking the napin coding region of BcNA1 has been engineered and demonstrated to function appropriately, as compared with the gene's endogenous expression, in transgenic rapeseed using the β-glucuronidase reporter gene. The B. rapa BcNA1 gene and a B. napus napin gene, gNa, share extremely high nucleotide homology not only throughout their coding regions, but over a DNA locus comprising 4.3 kb. We suggest the gNa gene was contributed by the original B. rapa progenitor of the amphidiploid B. napus.

Research into, and the environmental release of, transgenic rapeseed in China are overviewed and the environmental risks are assessed, focusing on competitive survival ability, gene dispersal and biodiversity impact of transgenic rapeseed. It is concluded that transgenic rapeseed has a higher probability of gene dispersal when compared with other major crops. Brassica napus may transfer genes through pollen and seeds to vegetables and wild species of B. rapa and B. juncea, for which China is the biodiversity centre and also the country of highest consumption. It is considered that the risk of gene dispersal is present, but can be reduced to an acceptable limit. Commercialization of transgenic rapeseed should not be stopped, but should be built on a safe and sound basis by building a reasonable management system. Awarenes of biosafety considerations for transgenic rapeseed should be strengthened, and a technical platform of genetically modified organism (GMO) detection and monitoring should be properly established. Countermeasures against environmental risks are also discussed.