Transient gene expression of β-glucuronidase in citrus thin epicotyl transversal sections using particle bombardment

Abstract

Studies were carried out to optimize the conditions for transient gene expression through particle bombardment on Carrizo citrange (Citrus sinensis × Poncirus trifoliata) thin epicotyl sections. The best conditions for transient GUS expression were: M-25 tungsten particles,1550 psi helium pressure, 9 cm distance between specimen and DNA/particle holder and culture of explants in a high osmolarity medium (0.2 M mannitol + 0.2 M sorbitol) 4 h prior and 20 h after bombardment. Under these conditions, an average of 102 blue spots per bombardment (20 explants/plate) were achieved. This protocol is currently being used for transformation of Carrizo citrange and sweet orange (Citrus sinensis).