Abstract
Plant-specific Dof transcription factors are involved in various processes unique to plants. Here we show the presence of 19 putative Dof genes in Physcomitrella patens (PpDof1-19) and one Dof gene in the green alga Chlamydomonas reinhardtii (CrDof), suggesting that the origin of the Dof transcription factors pre-dates the divergence of the green algae and the ancestors of terrestrial plants. Phylogenic analysis classified Dof genes into three groups, one of which includes PpDof1-6, CrDof and angiosperm Dof genes. Further characterization of PpDof1-6 genes revealed intimate relationships between PpDof1 and 2, PpDof3 and 4, and PpDof5 and 6. We therefore generated single knock out lines for each gene and double knock out lines in which both closely related Dof genes were disrupted. Among them, the PpDof1 PpDof2 double knock out line was found to show abnormal growth. We are currently performing more detailed analyses of this line.
