Development of ABA Antagonists to Overcome ABA- and Low Temperature-Induced Inhibition of Seed Germination in Canola, Lentil, and Soybean

ABA antagonists have potential application as growth regulators to improve germination and seedling growth at low temperatures for oilseeds and pulses grown in regions with short seasons such as those in western Canada. Towards development of practical ABA antagonists, a series of 3 '-substituted ABA analogs were synthesized and screened in seed germination assays in canola (Brassica napus), lentil (Lens culinaris), and soybean (Glycine max) at low temperature and in overcoming exogenous ABA. The most promising analog, ABA 1009, was selected for further germination testing of dose responses in canola, lentil, and soybean. Analog ABA 1009 at 100 mu M was effective in overcoming ABA (10 mu M)-induced inhibition for canola, lentil, and soybean germination at ambient temperature, and also promoted germination at low temperature for canola (5 degrees C).