Soybean Efficient Agrobacterium-mediated Genetic Transformation And Heat Shock Control Switch To The Removal Of Exogenous Genes Of Genetically Modified Plants

Here, we report the establishment of an efficient in vitro shoot organogenesis regeneration system for soybeans [Glycine max (L.) Merr.]. Mature soybean seeds were soaked for 24 h, the embryonic tips were collected and cultured on MSB5 medium supplemented with 3.5 mg/L-1 BAP for 24 h, and explants were transferred to MSB5 medium supplemented with 0.2 mgL-1 BAP and 0.2 mgL-1 IBA. Use of embryonic tips yielded a higher regeneration frequency (87.7%) than regeneration systems using cotyledonary-nodes (40.3%)and hypocotyl segments(56.4%)as starting materials. Regenerated embryonic tips were inoculated with Agrobacterium tumefaciens strain EHA105, which contains binary vector pCAMBIA2301, and cultured for 20 h. Our results showed that the T-DNA transfer efficiency reached up to 78.2% and the transformation efficiency reached up to 15.8%. These data indicate that the embryonic tip regeneration system can be used for efficient, effective Agrobacterium-mediated transformation.