摘要：SummaryRoot, shoot, and lateral meristems are the main regions of cell proliferation in plants. It has been proposed that meristems might have evolved dedicated transcriptional networks to balance cell proliferation. Here, we show that basic helix-loop-helix (bHLH) transcription factor heterodimers formed by members of the TARGET OF MONOPTEROS5 (TMO5) and LONESOME HIGHWAY (LHW) subclades are general regulators of cell proliferation in all meristems. Yet, genetics and expression analyses suggest specific functions of these transcription factors in distinct meristems, possibly due to their expression domains determining heterodimer complex variations within meristems, and to a certain extent to the absence of some of them in a given meristem. Target gene specificity analysis for heterodimer complexes focusing on theLONELY GUYgene targets further suggests differences in transcriptional responses through heterodimer diversification that could allow a common bHLH heterodimer complex module to contribute to cell proliferation control in multiple meristems.Graphical abstractDisplay OmittedHighlights•Expression of TMO5 and LHW bHLH clade members varies in distinct meristems•Single mutant analyses reveal functional specificity in meristems•Variations in TMO5/LHW heterodimer complexes affect target gene regulation•TMO5/LHW complexes are regulators of cell proliferation in all plant meristemsNatural sciences; Biological sciences; Plant biology; Molecular plant pathology
