Example 12
Plant transformation—The Arabidopsis thaliana var Columbia (To plants) were transformed according to the Floral Dip procedure [Clough S J, Bent A F. (1998) Floral dip: a simplified method for Agrobacterium-mediated transformation of Arabidopsis thaliana. Plant J. 16(6): 735-43; and Desfeux C, Clough S J, Bent A F. (2000) Female reproductive tissues were the primary targets of Agrobacterium-mediated transformation by the Arabidopsis floral-dip method. Plant Physiol. 123(3): 895-904] with minor modifications. Briefly, Arabidopsis thaliana Columbia (C010) T0 plants were sown in 250 ml pots filled with wet peat-based growth mix. The pots were covered with aluminum foil and a plastic dome, kept at 4° C. for 3-4 days, then uncovered and incubated in a growth chamber at 18-24° C. under 16/8 hours light/dark cycles. The T0 plants were ready for transformation six days before anthesis.
Single colonies of Agrobacterium carrying the binary vectors harboring the genes of some embodiments of the invention were cultured in YEBS medium (Yeast extract 1 gr/L, Beef extract 5 gr/L, MgSO4*7H2O, Bacto peptone 5 gr/L) supplemented with kanamycin (50 mg/L) and gentamycin (50 mg/L). The cultures were incubated at 28° C. for 48 hours under vigorous shaking to desired optical density at 600 nm of 0.85 to 1.1. Before transformation into plants, 60 μl of Silwet L-77 was added into 300 ml of the Agrobacterium suspension.
Transformation of T0 plants was performed by inverting each plant into an Agrobacterium suspension such that the above ground plant tissue was submerged for 1 minute. Each inoculated T0 plant was immediately placed in a plastic tray, then covered with clear plastic dome to maintain humidity and was kept in the dark at room temperature for 18 hours to facilitate infection and transformation. Transformed (transgenic) plants were then uncovered and transferred to a greenhouse for recovery and maturation. The transgenic T0 plants were grown in the greenhouse for 3-5 weeks until siliques were brown and dry, then seeds were harvested from plants and kept at room temperature until sowing.
For generating T1 and T2 transgenic plants harboring the genes of some embodiments of the invention, seeds collected from transgenic T0 plants were surface-sterilized by exposing to chlorine fumes (6% sodium hypochlorite with 1.3% HCl) for 100 minutes. The surface-sterilized seeds were sown on culture plates containing half-strength Murashig-Skoog (Duchefa); 2% sucrose; 0.5% plant agar; 50 mg/L kanamycin; and 200 mg/L carbenicylin (Duchefa). The culture plates were incubated at 4° C. for 48 hours and then were transferred to a growth room at 25° C. for three weeks. Following incubation, the T1 plants were removed from culture plates and planted in growth mix contained in 250 ml pots. The transgenic plants were allowed to grow in a greenhouse to maturity. Seeds harvested from T1 plants were cultured and grown to maturity as T2 plants under the same conditions as used for culturing and growing the T1 plants.
