In plant tissue culture, to obtain a regenerated plant, it is general to add plant growth regulators (PGRs) to the culture medium to induce plant differentiation; however, PGR conditions (hormone types, concentrations, etc.) vary depending on the explant materials (plant species, tissue type, age, etc.). Differentiation-inducing conditions have been established mainly in model plant species, but not many in practical species yet. In recent years, it has been reported that cellular differentiation (dedifferentiation and redifferentiation) was achieved by ectopic expression of the transcription factor, designated as Developmental Regulator (DR), which is involved in plant development and morphogenesis. If heterologous DR gene expression can be substituted for the external PGR application in inducing cellular differentiation, it would reduce the laborious work and time because genetic modification experiments can be performed without the effort required to examine PGR conditions. We have investigated the autonomous cellular differentiation by heterologous DR expressions. Recently, we have succeeded in the induction of autonomous callus and shoot differentiation from transgenic cells expressing modified Arabidopsis DRs in some plant species under PGR-free culture conditions. Using tobacco transgenic cells expressing DRs, changes in the internal gene expression and phytohormone levels were analyzed. In this congress, we report these findings and the ongoing study to improve the systems aiming for future practical use.