High-frequency plant regeneration frbm Astragalus melilotoides via somatic embryogenesis or organogenesis

【作者】 侯岁稳； 贾敬芬；

【Author】 Hou Sui-Wen Jia Jing-Fen(1 School of Life Science, Lanzhou University, Lanzhou 730000 2 School of Life Science, Northwest University, Xi’an 710069

【机构】 兰州大学生命科学学院； 西北大学生命科学学院；

【摘要】 <正> Astragalus melilotoides pall, is widely cultivated in many arid and desert regions of northChina for improving pasture because it is very nutritious to livestock. The plant can also be utilized as windbreaks or for crop rotation, sand-fixation and desalination because of its tolerance to drought, coldness, salinity and disease. Biotechnological approaches such as somatic hybridization and genetic transformation can be used for not only improving this crop, but also transferring its favorable resistant characters to other legumes. Here we reported a highly efficient and reproducible procedure developed for plant regeneration from hypocotyl or hypocotyl- and stem-derived calli of Astragalus melilotoides via somatic embryogenesis or organogenesis. High frequency of somatic embryos was induced directly from hypocotyl explants on MS supplemented with NAA (2.69 μM) and BA (4.44 μM) within 5 weeks. The development of somatic embryos was asynchronous and the globular, heart, torpedo and cotyledonary somatic embryos could be observed in the course. All of the somatic embryos developed in a single state and could be separated from hypocotyls easily. Some somatic embryos developed directly into whole plantlets with well-formed shoots and roots on the same medium. Three types of calli were induced when hypocotyl and stem segments were cultured on MS medium containing 2,4-D (9.05 μM) and BA (2.22 or 4.44 μM). Indirect somatic embryos or adventitious buds were initiated from hypocotyl-derived calli and only adventitious buds were formed from stem-derived calli on MS added 2.69 μM NAA with 4.44 or 8.89 μM BA. Many plantlets developed from somatic embryos or organogenetic buds when they were transferred on growth hormone-free MS medium or MS with 14.78 μM IBA after 3 weeks in culture, respectively. Somatic embryos induced directly from hypocotyls are more desirable because they can produce genetically stable plantlets and this is most suitable for plant genetic transformation. This regeneration system may be useful for the improvement of A. melilotoides by means of genetic manipulations.更多还原

【Abstract】 Astragalus melilotoides pall, is widely cultivated in many arid and desert regions of northChina for improving pasture because it is very nutritious to livestock. The plant can also be utilized as windbreaks or for crop rotation, sand-fixation and desalination because of its tolerance to drought, coldness, salinity and disease. Biotechnological approaches such as somatic hybridization and genetic transformation can be used for not only improving this crop, but also transferring its favorable resistant characters to other legumes. Here we reported a highly efficient and reproducible procedure developed for plant regeneration from hypocotyl or hypocotyl- and stem-derived calli of Astragalus melilotoides via somatic embryogenesis or organogenesis. High frequency of somatic embryos was induced directly from hypocotyl explants on MS supplemented with NAA (2.69 μM) and BA (4.44 μM) within 5 weeks. The development of somatic embryos was asynchronous and the globular, heart, torpedo and cotyledonary somatic embryos could be observed in the course. All of the somatic embryos developed in a single state and could be separated from hypocotyls easily. Some somatic embryos developed directly into whole plantlets with well-formed shoots and roots on the same medium. Three types of calli were induced when hypocotyl and stem segments were cultured on MS medium containing 2,4-D (9.05 μM) and BA (2.22 or 4.44 μM). Indirect somatic embryos or adventitious buds were initiated from hypocotyl-derived calli and only adventitious buds were formed from stem-derived calli on MS added 2.69 μM NAA with 4.44 or 8.89 μM BA. Many plantlets developed from somatic embryos or organogenetic buds when they were transferred on growth hormone-free MS medium or MS with 14.78 μM IBA after 3 weeks in culture, respectively. Somatic embryos induced directly from hypocotyls are more desirable because they can produce genetically stable plantlets and this is most suitable for plant genetic transformation. This regeneration system may be useful for the improvement of A. melilotoides by means of genetic manipulations.更多还原