Regeneration and Transformation Through Somatic Embryogenesis,and Determination of Cold Stress Tolerance in Ground Cover Chrysanthemum cv. Fall Color
HONG Bo1, TONG Zheng1, LI Qiu-hua1, MA Chao1, KASUGA Mie2, YAMAGUCHI-SHINOZAKI Kaziko2, GAO Jun-ping1 (1Department of Ornamental Horticulture and Landscape Architecture, China Agricultural University, Beijing 100094; 2Biological Resources Division, Japan International Research Center for Agricultural Sciences, 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686 Japan)
【Objective】This article aimes at breeding of new materials with tolerance to cold conditions in ground-cover chrysanthemum [Dendranthema grandiflorum (Ramat.) Kitamura]. 【Method】Young leaf explants of the cultivar, Fall color, were used to determine the optimum conditions of both concentration of plant growth regulator and induction time to establish a high frequency regeneration system through somatic embryogenesis. 【Result】The explants incubated for 15 d on IM containing 0.75 mg·L-1 2,4-D generated not only embryo callus tissue, but also somatic embryos. The somatic embryos emerged shoot with 93% of shoot regeneration rate after further regeneration culture. AtDREB1A, a stress-inducible transcription factor, driven by 35S cauliflower mosaic virus (CaMV) promoter was transferred into Fall Color through Agrobacterium-mediated transformation. Seed germination and seedling growth at low temperature, and plant growth in winter cultivated in open-field were much improved in transgenic plants compared to WT plants. 【Conclusion】These results indicate that the authors have established successfully the embryo-generation system of ground-cover cv. Fall color, and have obtained successfully the transgenic lines with tolerance to open-field conditions in winter.