Cucumber (Cucumis sativus L.) with heterologous poly-γ-glutamic acid has skin moisturizing, whitening and anti-wrinkle effects

Three genes involved in poly-γ-glutamic acid(γ-PGA)synthesis cloned from Bacillus licheniformis were transformed into cucumber for the first time. Compared with control, its water content increased by 6–14 % and water loss rate decreased by 11–12 %. In zebrafish and human skin experiments, the moisturizing effect of transgenic cucumber was significantly higher than that of CK, γ-PGA and hyaluronic acid group. Transgenic cucumber reduced facial wrinkles and roughness by 19.58 % and 24.97 %, reduced skin melanin content by 5.27 %, increased skin topological angle and L-value by 5.89 % and 2.49 %, and increased the R2 and Q1 values of facial elasticity by 7.67 % and 5.64 %, respectively. The expressions of aqp3, Tyr, silv and OCA2 were down-regulated, eln1, eln2, col1a1a and col1a1b were up-regulated in zebrafish after treated with transgenic cucumber. This study provides an important reference for the endogenous synthesis of important skin care functional molecules in plants.