Abstract: The minimal linear smGFP gene cassette was constructed and transiently expressed in onion epidermal cell by adjusting the osmotic pressure of the transformation buffer. Strong fluorescence of green fluorescent protein was observed in cytoplasm and nucleus by fluorescence microscope, which proved that smGFP gene cassettes transformed into onion epidermal cell and kept its integrity. Exogenous gene was penetrated into host cell directly without any other force, such as particle bombardment, electransformation and microinjection. Therefore, it induces less damage to the host cells and has a wide range of application. In addition, this method is easily operated and less costly.

Key words: smGFP, direct transformation, transient expression, minimal linear transformation cassette