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Screening for stable transformants and stability of beta-glucuronidase gene expression in suspension cultured cells of tall fescue (Festuca arundinacea)

Kuai, B., Morris, P.
Plant cell reports 1996 v.15 no.11 pp. 804-808
Festuca arundinacea, genetic transformation, cell suspension culture, transgenic plants, gene expression, genetic stability, clones, genetic variation, beta-glucuronidase, enzyme activity, callus, cytidine, genomics
By screening cell colonies derived from protoplasts of tall fescue (Festuca arundinacea), transformed with a rice actin-1-promoter-beta-glucuronidase gene construct, several beta-glucuronidase positive callus clones were obtained. Two callus clones with different GUS expression were derived from these. One was light blue after X-gluc staining, and expression of the beta-glucuronidase gene was stable over repeated subculture, while another stained intensely blue, and expression of the beta-glucuronidase gene was unstable. Southern blot analysis showed that only one copy of the beta-glucuronidase gene was integrated into the genome, and that these two clones appeared to have the same integration pattern. Treatment with 5-azacytidine maintained GUS expression in the unstable line but had no effect on reactivating expression of the GUS gene after expression had been lost. Following the screening procedure the callus clones would only regenerate albino plants.