Title: Biolistic and Agrobacterium-mediated transient expression of UidA in Triticale immature embryos
Abstract: The development of a protocol to transform a recalcitrant species like triticale (×Triticosecale Wittmack), based on biolistic or Agrobacterium tumefaciens, requires the identification and optimisation of the factors affecting DNA delivery.We have used immature embryos from the triticale doubled-haploid line 'ATOPE-22' in order to compare the transient expression of the uidA gene delivered by both biolistic and Agrobacterium systems.Particle bombardment experiments were made with gold micro-particles (1 µm diameter) coated with the plasmid pAHGUS, using Biolistic ® PDS-1000/He (BioRad) equipment.The conditions that gave the maximun number of foci per immature embryo bombarded were 1100 psi of helium pressure and 6 cm of shooting distance.With Agrobacterium, we analysed the time required by the embryos in pre-culturing and the time of inoculation with the Agrobacterium strain AGL1 harbouring the plasmid combination pAL154 and pAL156 which was based on the pSoup/pGreen series.The times required to produce the maximum number of foci per immature embryo were 0.5 hours and 2-3 hours, respectively.