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Received: 4 August 2009 / Accepted: 8 January 2010 / Published online: 23 February 2010 / Editor: D. T. Tomes
© The Society for In Vitro Biology 2010
Abstract Canola is one of the most important cash crops in Canada, and a national project named "Designing Oilseeds for Tomorrow's Market" was undertaken to improve seed meal quality of this strategically important crop. As a part of this project, our group is focusing on identifying seed coat-specific promoters for canola (Brassica napus). These promoters will be used to genetically modify canola seed coat to reduce or eliminate anti-nutritional components from the meal. The Arabidopsis thaliana BAN promoter (AtBANpro) and δVPE promoter (AtδVPEpro) were isolated and fused to GUS reporter gene to generate transgenic canola plants. These plants were analyzed by GUS staining and microtome sectioning which showed that both promoters are seed coat-specific in canola: AtBANpro in inner seed coat layer and AtδVPEpro in outer seed coat layer. Therefore, the two Arabidopsis promoters can be used to modify genes in seed coat of canola for further improving its seed qualities.
Keywords Seed coat * Promoter * Canola * BAN * VPE * Arabidopsis
Introduction
Canola (Brassica napus L.) was originally bred from rapeseed in Canada by Keith Downey and Baldur R. Stefansson in the early 1970s, and the word "canola" ("Canadian oil, low acid") was derived. Canola seed has a very low level of both erucic acid and glucosinolates (erucic acid <2% in the oil portion and glucosinolates <30 µmol/g in the meal portion) and is used for producing healthy oil for human consumption and better meal for animals feeds (Downey 1990). Although canola is mainly cultivated for its oil, the seeds are also naturally rich in protein (~36%). The overall amino acid composition is comparable to soybean protein. Soybean protein is in fact poor in cysteine and methionine content although richer in lysine compared to canola meal (Bell 1993). Furthermore, canola seed is also rich in vitamins and minerals, making it a potentially better animal feed supplement, but the market price for canola meal is about 60-70% relative to soybean meal mainly because of anti-nutritional factors (ANFs) associated with canola meal. A general consequence of ANFs is reduced inclusion of canola meal diet...