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Title: GREEN FLUORESCENT PROTEIN AS A SOLE SELECTABLE MARKER FACILITATES GENETIC TRANSFORMATION OF PAPAYA (CARICA PAPAYA L.)

Author
item ZHU, YUN - HARC
item AGBAYANI, R - HARC
item Moore, Paul

Submitted to: In Vitro Cellular and Developmental Biology - Plants
Publication Type: Abstract Only
Publication Acceptance Date: 1/10/2002
Publication Date: 8/2/2002
Citation: Vol. 38, abstract P1020.

Interpretive Summary: abstract only

Technical Abstract: A basic requirement for genetic transformation is the ability to segregate and culture cells that contain functioning transgenes from those cells that do not. Commonly this is accomplished by negative selection including a gene that confers resistance to a biocide such as an antibiotic or herbicide to eliminate susceptible cells not containing the transgenes. Negative selection for plant transformation is associated with a number of real and perceived problems that might be avoided through neutral or positive selection. Alternative selection methods are needed and one alternative with potential is that of visual selection. Transgenically expressed green fluorescent protein (GFP) of the jellyfish Aequorea victoria, visualized directly without the addition of exogenous substrates or cofactors, is not toxic to plant or mammalian cells, is very stable, and shows little photobleaching. We used green fluorescent protein, GFP, as a visual selectable marker to produce transformed papaya (Carica papaya) plants following microprojectile bombardment of embryogenic callus. GFP expression in the callus tissue was visualized under epifluorescence microscopy for the physical isolation of green fluorescent cells using very sharp forceps. GFP selection reduced the selection time to 3 to 4 weeks compared to a 3-month selection time on a geneticin (G418) antibiotic containing medium. Moreover, GFP selection increased the number of transformed papaya plants by about 6-fold compared to selection in the presence of antibiotics. Overall, GFP improved our throughput for transformation by about 18-fold while avoiding drawbacks associated with use of antibiotic resistance-based selection markers.