Callus induction,which results in fate transition in plant cells,is considered as the first and key step for plant regeneration.This process can be stimulated in different tissues by a callus-inducing medium(CIM),whic...Callus induction,which results in fate transition in plant cells,is considered as the first and key step for plant regeneration.This process can be stimulated in different tissues by a callus-inducing medium(CIM),which contains a high concentration of phytohormone auxin.Although a few key regulators for callus induction have been identified,the multiple aspects of the regulatory mechanism driven by high levels of auxin still need further investigation.Here,we find that high auxin induces callus through a H3 K36 histone methylation-dependent mechanism,which requires the methyltransferase SET DOMAIN GROUP 8(SDG8).During callus induction,the increased auxin accumulates SDG8 expression through a TIR1/AFBs-based transcriptional regulation.SDG8 then deposits H3 K36 me3 modifications on the loci of callus-related genes,including a master regulator WOX5 and the cell proliferation-related genes,such as CYCB1.1.This epigenetic regulation in turn is required for the transcriptional activation of these genes during callus formation.These findings suggest that the massive transcriptional reprogramming for cell fate transition by auxin during callus formation requires epigenetic modifications including SDG8-mediated histone H3 K36 methylation.Our results provide insight into the coordination between auxin signaling and epigenetic regulation during fundamental processes in plant development.展开更多
基金the National Natural Science Foundation of China(Grant Nos 32130010,31422008,and 31870256)startup funds from FAFU to T.X.,and FAFU Youth Fund(Grant No.XJQ202016)to J.M.
文摘Callus induction,which results in fate transition in plant cells,is considered as the first and key step for plant regeneration.This process can be stimulated in different tissues by a callus-inducing medium(CIM),which contains a high concentration of phytohormone auxin.Although a few key regulators for callus induction have been identified,the multiple aspects of the regulatory mechanism driven by high levels of auxin still need further investigation.Here,we find that high auxin induces callus through a H3 K36 histone methylation-dependent mechanism,which requires the methyltransferase SET DOMAIN GROUP 8(SDG8).During callus induction,the increased auxin accumulates SDG8 expression through a TIR1/AFBs-based transcriptional regulation.SDG8 then deposits H3 K36 me3 modifications on the loci of callus-related genes,including a master regulator WOX5 and the cell proliferation-related genes,such as CYCB1.1.This epigenetic regulation in turn is required for the transcriptional activation of these genes during callus formation.These findings suggest that the massive transcriptional reprogramming for cell fate transition by auxin during callus formation requires epigenetic modifications including SDG8-mediated histone H3 K36 methylation.Our results provide insight into the coordination between auxin signaling and epigenetic regulation during fundamental processes in plant development.
