Genetic transformation of Linum by particle bombardment

Linseed flax (Linum usitatissimum L.) was transformed by bombarding hypocotyl tissues with gold particles coated with plasmid DNA carrying the P-glucuronidase (GUS) (uid-A) and neomycin phosphotransferase II (npt-II) genes. Transient expression of the introduced P-glucuronidase gene was used to study factors influencing the DNA delivery, while progeny analyses confirmed stable transformation. The efficiency of DNA delivery, uptake and expression was significantly affected by the duration of hypocotyl preculture, bombardment distances, the level of chamber vacuum, the quantity of DNA, and the size of particles. Nineteen independent GUS-positive shoots were recovered and regenerated into whole plants, from which 10 plants successfully produced viable seeds. Analysis of T-1 and T-2 self pollinated progeny for histochemical and fluorometric GUS assays and polymerase chain reaction (PCR) analyses for uid-A, plus npt-II PCR and germination assays in progeny plants demonstrated that the transgenes were expressed in selected plants and transmitted to progeny, usually via a single Mendelian locus. The results show that particle bombardment can be used to produce transgenic Linum plants. The system is rapid, simple and offers an alternative to Agrobacterium methods.