Abstract
Cell fate change from matured cells to stem cells is a well-known feat of plants, but the molecular mechanisms are mostly unexplored. Using the moss Physcomitrella patens, we have previously reported that light signals mediated by phytochromes and cryptochromes are required for cell fate change from a leaf cell to a stem cell. To elucidate the downstream mechanism of light signaling, we analyzed the function of SBP-box genes that were suggested to be negative effectors of cryptochrome signaling. Cell fate change was suppressed in plants that were conditionally expressed the PpSBP4, but promoted in plants that were conditionally expressed the dominant repression fusion protein of PpSBP4 (PpSBP4-SRDX). Furthermore, the transcript levels of PpSBP4 were reduced during the process of cell fate change. These results suggest that PpSBP4 act as negative regulator of cell fate change from leaf cells to protonemal stem cells.
