Stable transformation of lettuce cultivar South Bay from cotyledon explants

Abstract

Transgenic plants of lettuce cultivar (cv.) 'South Bay' were produced by using Agrobacterium tumefaciens vectors containing the /3-glucuronidase (GUS) reporter gene and the NPT II gene for kanamycin resistance as a selectable marker. High frequency of transformation, based on kanamycin resistance and assays for GUS expression, was obtained with 24 to 72-h-old cotyledon explants cocultivated for 48 h with Agrobacterium tumefaciens. After the cocultivation period, the explants were placed in selection medium containing 50 or 100mgl -I of kanamycin, 100mg1-1 cefotaxime and 500mg1-1 carbenicillin for 10 days. Surviving explants were transferred every 14 days on shoot elongation medium. Progenies of R 0 plants demonstrated linked monogenic segregation for kanamycin resistance and GUS activity.

An improved method for transformation of lettuce by Agrobacterium tumefaciens with a gene that confers freezing resistance

“…When we used the first protocol, (Torres et al, 1993), we got no transformed explant, probably because another cultivar was used (South Bay). We accomplished some adaptations based on protocols of Torres et al (1993), andHorsch et al (1988).…”

“…We accomplished some adaptations based on protocols of Torres et al (1993), andHorsch et al (1988). The major modifications related to the first one are listed here.…”

“…Lettuce (Lactuca sativa L. c.v. Grand Rapids) was chosen as a model plant due to its fast growth and agronomic value. The protocol described by Torres et al 1993 to construct transgenic lettuce lineages by Agrobacterium tumefaciens was not adequate to obtain transgenic lettuce plants, probably due to incompatibility with the cultivar involved. This paper describes adaptations and modifications to improve transformation and regeneration efficiency of Grand Rapids lettuce cultivar, as a model to test the resistance to freezing temperature.…”

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ABSTRACT

An efficient method for constructing transgenic lettuce cultivars by Agrobacterium tumefaciens was described by Torres et al, 1993. In the present work, an improvement of the above procedure is described and applied to transform the cultivar Grand Rapids with a mutated P5CS gene.

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Transformação genética da batata cultivar Achat via Agrobacterium tumefaciens

“…Em períodos prolongados de co-cultivos (72 e 96 h) ocorreu um aumento na proliferação da A. tumefaciens, tornando difí-cil a sua eliminação do meio com os antibióticos empregados na transformação. Resultados semelhantes foram obtidos em outros trabalhos de transformação (Sheerman & Bevan, 1988;Torres et al, 1993;Forreiter et al, 1997;Torres et al, 1999) em que o período de co-cultivo de 48 h também foi o mais adequado para a produção de plantas transgênicas.…”