HISTORICAL PERSPECTIVE ESSAY The Scientific Roots of Modern Plant Biotechnology

One of the stellar achievements of twentieth century plant biology was the genetic transformation of somatic cells enabling the regeneration of whole plants that were stably transformed and capable of transmitting the inserted genetic material to subsequent generations. This achievement grew out of three independent lines of research initiated early in the twentieth century: plant tissue culture, regeneration of plants from single somatic cells, and the study of crown gall disease. The early discoveries made in these areas represent a combination of basic scientific research and technological innovations and led to the development of genetically transformed crop species expressing traits unobtainable by conventional breeding. Each of these fields can be traced back to a single research publication (Haberlandt, 1902; Smith and Townsend, 1907; White, 1939a) that later came to be considered as the foundation of the field. It is instructive to follow how these three fields were established, progressed, converged, and finally coalesced. Early workers, of course, could not know the ultimate way in which their discoveries would be applied to modern plant biotechnology (Figure 1). Instead, they posed questions that were of interest to them and to the scientific communities of which they were a part, and some of their discoveries led in directions that would later prove to be productive in the progression to biotechnology. This essay is intended to provide a review of the crucial discoveries that ultimately led to modern plant biotechnology and show how they contributed to this progression.