optimization of transient expression of uida gene in androgenic embryos of wheat (triticum aestivum l. cv. falat) via particle pombardment

haploid microspore-derived embryos (mdes) of wheat were obtained by in vitro androgenesis. these  embryos were employed to evaluate the transient expression of gus gene (uida) following particle bombardment. using the bio-rad pds-1000/he system, the physical parameters including rupture disk pressure (900, 1100 and 1350 psi); microprojectile travel distance (6 and 9 cm); gold particles size (0.6 mm, 1 mm and 1.6 mm), dna and microcarrier concentrations (0.5 mg of dna with 150 μg of gold particles or 1.0 μg of dna with 300 mg of gold particles/bombardment) and bombardment numbers (1x (single) and 2x (double)) were assessed. the effect of high osmoticum in the bombardment medium (0.3 m mannitol and 0.4 m maltose) and the age of embryos were also evaluated.  optimal expression in mdes was obtained using the following conditions of double bombardment at 1350 psi, 9 cm target distance, a 1 mm gold particle size, 1.0 mg of dna with 300 mg of gold particles/bombardment, and osmotic pretreatment of 4-6 weeks old embryos using 0.4 m maltose for 6 h before and 16 h after bombardment. the optimized transformation protocol presented in this study is expected to improve devalopment of commercial transgenic wheat lines expressing desirable agronomic traits.