Improved Hormone Formulation for Agrobacterium-mediated Lettuce Genetic Transformation

Objective Lettuce genetic transformation was optimized by reformulating the hormones used in culture medium.

Methods Roman lettuce BINFEN-3 was used as the receptor to construct the pKSE401-MYB75 knockout vector to be introduced into Agrobacterium GV3101 for the transformation. On the basic MS medium with the types and concentrations of antibiotics kept constant, varied ratios of 6-BA, NAA, KT, and 2,4-D were added for pre-culture and co-culture. Schemes A, B, C, and D were designed for the formulation optimization.

Results For efficient lettuce bud induction, a pre-culture/co-culture medium of MS + 0.1mg NAA·L⁻¹ + 0.05mg 6-BA·L⁻¹ and a differentiation/selective medium of MS + 0.1mg NAA·L⁻¹ + 0.05mg 6-BA·L⁻¹ + 300mg Tim·L⁻¹ + 50mg Kan·L⁻¹ were used. A callus rate of 99%, a callus differentiation rate of 50%, and a conversion efficiency of positive seedlings reaching 6.4% were obtained on the culture.

Conclusion The genetic transformation of BINFEN-3 was achieved with the optimized antibiotic ratio for the Agrobacterium-mediated callus regeneration.