Evaluation of selectable markers for rice transformation

Area of Science:

• Plant Biotechnology
• Molecular Biology
• Genetics

Background:

• Dicotyledonous plant transformation systems are well-established.
• The suitability of these systems for monocotyledonous plants like rice (Oryza sativa) requires investigation.
• Efficient selection methods are crucial for successful plant transformation.

Purpose of the Study:

• To evaluate the efficacy of various promoters and selectable markers for rice callus transformation.
• To compare promoter strength in rice (Oryza sativa) and tobacco (Nicotiana tabacum) protoplasts.
• To identify suitable selective agents and resistance genes for rice transformation.

Main Methods:

• Transient expression assays in rice and tobacco protoplasts.
• Sensitivity testing of rice callus to various selective agents (methotrexate, phosphinothricin, bleomycin, G418, hygromycin, kanamycin).
• Stable transformation experiments using resistance genes and Southern blot analysis.

Main Results:

• The octopine T-DNA 2' promoter showed significantly higher efficiency in rice protoplasts compared to other promoters (CAMV 35S, nos, 1').
• Rice callus exhibited sensitivity to phosphinothricin, G418, hygromycin, methotrexate, and bleomycin.
• Phosphinothricin and G418 resistance genes enabled transformed rice callus growth on selective media, while methotrexate resistance was ineffective.

Conclusions:

• The octopine T-DNA 2' promoter is a strong candidate for rice transformation.
• Phosphinothricin and G418 are effective selective agents for rice transformation.
• Optimized promoter and selectable marker systems are essential for advancing rice genetic engineering.