Methods for introducing a functionalized linear nucleic acid cassette molecule of interest into a plant cell comprising a cell wall include use of nanoparticles. In some embodiments, the cell comprising a cell wall is a cultured plant cell. Methods include genetically or otherwise modifying plant cells and for treating or preventing disease in any plant, especially crop plants. Transgenic plants include a nucleic acid molecule of interest produced by regeneration of whole plants from plant cells transformed with functionalized linear nucleic acid cassette molecules.