5] Liposomes as carriers for the transfer and expression of nucleic acids into higher plant protoplasts

Abstract

This chapter presents an alternative method based on the encapsulation of nucleic acids into large unilamellar liposomes. This technique has proved to yield high viral RNA-mediated transfection values, and in one case, is shown to be the only one allowing successful transfection of protoplasts with potyviral RNA. In addition, encapsulation of recombinant DNA into such liposomes followed by the interaction with protoplasts is shown to enable the recovery of regenerated tobacco plants carrying and expressing the neo gene from Escherichia coli —that is, transformed to kanamycin resistance. The encapsulation of nucleic acids into a variety of liposome preparations and their interaction with protoplasts is reviewed. An analysis of the data indicates that nucleic acids trapped in liposomes produced by the reversed-phase evaporation method can be transferred efficiently into plant protoplasts and can be biologically expressed in the cytoplasm and in the nucleus of the recipient cells. In most cases, liposomes are chiefly composed of phosphatidylserine, and therefore, negatively charged. The technique described in the chapter used to transfer and to express tobacco mosaic virus (TMV) RNA and the recombinant plasmid pLGV23 neo in tobacco protoplasts. With minor modifications, this method can be applied to a wide variety of plant protoplasts and nucleic acids.