To establish an efficient plant regeneration system from cell suspension cultures of Euonymus alatus, embryogenic callus formation from immature embryos was investigated. The highest frequency of embryogenic callus formation reached 50% when the immature zygotic embryos were incubated on Murashige and Skoog (MS) medium supplemented with 1 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D). At higher concentrations of 2,4-D (over 2 mg/L), the frequency of embryogenic callus formation declined significantly. The total number of somatic embryos development was highest with the 3% (w/v) sucrose treatment, which was found to be the optimal concentration for somatic embryo formation. Activated charcoal (AC) and 6-benzyladenine (BA) significantly increased the frequency of plantlet conversion from somatic embryos, but gibberellic acid (GA3) had a negative effect on plantlet conversion and subsequent development from somatic embryos.
Fig: Somatic embryogenesis and plant regeneration from immature zygotic embryo cultures of E. alatus. (a) Embryogenic and nonembryogenic callus formation from zygotic embryo; (b) proliferation of embryogenic callus; (c) numerous globular-shaped somatic embryos formation from embryogenic callus; (d,e) heart-shaped somatic embryo; (f) torpedo-shaped somatic embryo; (g) cotyledonary somatic embryo; (h) germination of somatic embryo; (i) development of numerous somatic embryos from embryogenic calluses cultured on MS basal medium; (j) plantlet developed from somatic embryo; (k) regenerated plant transplanted to potting soil. Arrows represent embryogenic (EC) and nonembryogenic callus (NEC). Scale bars represent 1 mm (a–c,g), 0.5 mm (d–f), and 1 cm (h–k), respectively.
Even though the cell suspension cultures were maintained for more than 1 year, cell aggregates from embryogenic cell suspension cultures were successfully converted into normal somatic embryos with two cotyledons. To our knowledge, this is the first successful report of a plant regeneration system of E. alatus via somatic embryogenesis. Thus, the embryogenic cell line and plant regeneration system established in this study can be applied to mass proliferation and production of pharmaceutical metabolite in E. alatus.
Woo, HA., Ku, S.S., Jie, E.Y. et al. Efficient plant regeneration from embryogenic cell suspension cultures of Euonymus alatus. Sci Rep 11,15120 (2021). https://doi.org/10.1038/s41598-021-94597-4