Divergent regeneration-competent cells adopt a common mechanism for callus initiation in angiosperms.

In tissue culture, the formation of callus from detached explants is a key step in plant regeneration; however, the regenerative abilities in different species are variable. While nearly all parts of organs of the dicot are ready for callus formation, mature regions of organs in monocot rice () and other cereals are extremely unresponsive to tissue culture. Whether there is a common molecular mechanism beyond these different regenerative phenomena is unclear. Here we show that the and rice use different regeneration-competent cells to initiate callus, whereas the cells all adopt () and during cell fate transition. Different from which maintains regeneration-competent cells in mature organs, rice exhausts those cells during organ maturation, resulting in regenerative inability in mature organs. Our study not only explains this old perplexity in agricultural biotechnology, but also provides common molecular markers for tissue culture of different angiosperm species.