Glick et al. (1998) proposed that ACC deaminase-containing bacteria attach to plant tissues and degrade ACC, click here the direct precursor of ethylene biosynthesis in plants that is exuded from the plant cell, and as a result, provide a sink for ACC and reduce plant ethylene biosynthesis.

Thus, the application of ACC deaminase may be used as a strategy to reduce ethylene levels during the transformation process and to increase A. tumefaciens-mediated transformation efficiency. Most recently, it has been reported that the introduction of ACC deaminase into A. tumefaciens increased the transient gene delivery efficiency of melon cotyledon explants when tested 3 days after infection (Nonaka et al., 2008a). However, the effect of ACC deaminase on A. tumefaciens-mediated stable transformation efficiency was not evaluated in that study. Canola is an

important source of vegetable oil, ranking second only to soybeans worldwide (Halfhill et al., 2002). In Selleck Ixazomib recent years, researches started to genetically modify canola to make it tolerant to heavy metals and other toxic compounds and use it for phytoremediation (Basu et al., 2001; Stearns et al., 2005), to produce pharmaceutically active proteins and edible vaccines (Giddings et al., 2000), and to improve it for producing biofuel (http://www.canolacouncil. org/biodiesel/). A considerable amount of work has been reported previously in an effort to improve A. tumefaciens-mediated transformation efficiency of canola, including choosing the best plant material for the transformation and optimization of the infection and regeneration protocols (Cardoza & Stewart, 2003; Zhang & Bhalla, 2004; Zhang et al., 2005; Bhalla & Singh, 2008). However, most of the studies used the model cultivar Brassica napus cv. Westar, which is an old spring cultivar

and is no longer grown in the fields due to some agronomic deficiencies. Because ALOX15 the transformation and regeneration of canola is genotype dependent, it is therefore important to evaluate and optimize the transformation protocols for commercialized cultivars. Both cultivars B. napus cv. Hyola 401 and cv. 4414RR are top canola spring hybrids and there are no reports to date regarding their transformation. In this study, an ACC deaminase-encoding gene was introduced into A. tumefaciens GV3101∷pMP90, and using the protocol established by Cardoza & Stewart (2003), transformation efficiency assays were performed using the canola model cultivar Westar and the two commercial cultivars Hyola 401 and 4414RR. These experiments allowed determination of the effect of ACC deaminase on A. tumefaciens-mediated transformation efficiency. The plasmid pPZP-eGFP (provided by Dr Barbara Moffatt, Department of Biology, University of Waterloo), a pPZP-RCS2 (Tzfira et al.