C. Walter et al., A BIOLISTIC APPROACH FOR THE TRANSFER AND EXPRESSION OF A GUSA REPORTER GENE IN EMBRYOGENIC CULTURES OF PINUS-RADIATA, Plant cell reports, 14(2-3), 1994, pp. 69-74
The biolistic(R) particle delivery system was used for the delivery of
DNA into embryogenic tissue culture cells of Pinus radiata D. Don. Se
veral experiments with varying parameters were performed to increase t
he delivery efficiency. Six different controlling elements were cloned
upstream of the beta-glucuronidase coding sequence (gusA reporter gen
e) and transient expression of the gusA reporter gene was compared thr
ee days after bombardment. The results clearly indicate a decrease in
transient expression as follows: pEmu-derivatives with the ocs-enhance
r-element > 2x CaMV 35S (with Kozak consensus-sequence) > 2x CaMV 35S
(without Kozak consensus sequence) > CaMV 35S (with Kozak consensus-se
quence) > CaMV 35S (without Kozak consensus sequence). Time course exp
eriments monitoring gusA expression showed a significant decrease in t
he number of blue spots 10-14 days after bombardment. A few blue clump
s however, were still detected 35 days after shooting. Embryo initials
expressing the gusA gene in all cells were also detected. The results
suggest that it will be possible to develop a reliable biolistic prot
ocol for stable integration of genes into Pinus radiata embryogenic cu
ltures which are capable of plant regeneration.