Studies of the mechanism of transgene integration into plant protoplasts: improvement of the transformation rate

Abstract

The production of transgenic plants by means of direct gene transfer to protoplasts is now a widely-used technique . The biological mechanisms underlying the transformation are still poorly understood, but many investigations have attempted to shed light on some components of this process . Varying the experimental conditions has in some cases led to better transformation rates, but further improvements of the protocols are possible . Such improvements will require a better understanding of how the alien DNA enters the cells, becomes integrated into the chromosomes and is treated as a part of the plant genome . Irradiation with sublethal doses of X-rays or UV-light has been shown to increase the transformation frequency, while certain drugs have been shown to act in a similar manner . The effects of these and other factors are discussed .Abbreviations: Aph-aphidicolin,ATF-absolutetransformationfrequency,BLM-bleomycin,CaMV-cauliflower mosaic virus, CAT -chloramphenicol acetyl transferase, CHO -Chinese hamster ovary cells, EF -enhancement factor, Nos -nopaline synthase, NPTII -neomycin phosphotransferase II, Ocs -octopine synthase, PEGpolyethyleneglycol, RTF -relative transformation frequency

Transgenic DNA integrated into the oat genome is frequently interspersed by host DNA

“…Genomic integration of transgenes has been associated with DNA replication and break-repair processes (24,(40)(41)(42). Increases in the frequency of transgene integration have been observed after applying agents that cause breaks in DNA, such as x-ray and UV irradiation, or after transformation during the S phase of the cell cycle, when an increased number of breaks in replicating DNA is present naturally.…”