γ-Aminobutyric acid a novel candidate for rapid induction in somatic embryogenesis of Liriodendron hybrid

The γ-aminobutyric acid is a non-protein amino acid with a so far unestablished role in Liriodendron hybrid somatic embryogenesis. In this study, we aimed to establish a rapid somatic embryo induction methodology, and to this end we investigated how GABA affects somatic embryo induction and development in Liriodendron hybrid. We successfully induced somatic embryos using embryogenic callus treated with different GABA concentrations. The addition of 6 mg/L GABA to MS basic medium showed a positive effect on the induction and maturation of somatic embryos, which had no effect on the structure of somatic embryos. GABA stimulated higher expression of LhWUS, LhCLV3 and LhWOX2 and an earlier LhCLV3 expression peak. In addition, we found that GABA affected the plant morphological growth, changing the number of lateral roots, root length and stem diameter of plantlets germinated from somatic embryos of Liriodendron hybrid. However, there was no significant effect on plant height and leaf number. Our research may provide benefits for the improvement of somatic embryogenesis protocols by using GABA, which lays a good foundation to study the molecular mechanism that GABA regulates somatic embryo induction and development.