Plant cells in damaged tissue can be reprogrammed to acquire pluripotency and induce callus formation.However,in the aboveground organs of many species,somatic cells that are distal to the wound site become less sensi...Plant cells in damaged tissue can be reprogrammed to acquire pluripotency and induce callus formation.However,in the aboveground organs of many species,somatic cells that are distal to the wound site become less sensitive to auxin-induced callus formation,suggesting the existence of repressive regulatory mechanisms that are largely unknown.Here we reveal that submergence-induced ethylene signals promote callus formation by releasing post-transcriptional silencing of auxin receptor transcripts in non-wounded regions.We determined that short-term submergence of intact seedlings induces auxin-mediated cell dedifferentiation across the entirety of Arabidopsis thaliana explants.The constitutive triple response 1-1(ctr1-1)mutation induced callus formation in explants without submergence,suggesting that ethylene facilitates cell dedifferentiation.We show that ETHYLENE-INSENSITIVE 2(EIN2)post-transcriptionally regulates the abundance of transcripts for auxin receptor genes by facilitating microRNA393 degradation.Submergence-induced calli in non-wounded regions were suitable for shoot regeneration,similar to those near the wound site.We also observed submergence-promoted callus formation in Chinese cabbage(Brassica rapa),indicating that this may be a conserved mechanism in other species.Our study identifies previously unknown regulatory mechanisms by which ethylene promotes cell dedifferentiation and provides a new approach for boosting callus induction efficiency in shoot explants.展开更多
基金This work was supported by the Basic Research Program provided by the National Research Foundation of Korea(NRF-2019R1C1C1002045 and NRF-2021R1A2C4002413)the New Breeding Technologies Development Program(project PJ0165302022)provided by the Rural Development Administration of Korea,and the KRIBB Research Initiative Program(KGM5372221).
文摘Plant cells in damaged tissue can be reprogrammed to acquire pluripotency and induce callus formation.However,in the aboveground organs of many species,somatic cells that are distal to the wound site become less sensitive to auxin-induced callus formation,suggesting the existence of repressive regulatory mechanisms that are largely unknown.Here we reveal that submergence-induced ethylene signals promote callus formation by releasing post-transcriptional silencing of auxin receptor transcripts in non-wounded regions.We determined that short-term submergence of intact seedlings induces auxin-mediated cell dedifferentiation across the entirety of Arabidopsis thaliana explants.The constitutive triple response 1-1(ctr1-1)mutation induced callus formation in explants without submergence,suggesting that ethylene facilitates cell dedifferentiation.We show that ETHYLENE-INSENSITIVE 2(EIN2)post-transcriptionally regulates the abundance of transcripts for auxin receptor genes by facilitating microRNA393 degradation.Submergence-induced calli in non-wounded regions were suitable for shoot regeneration,similar to those near the wound site.We also observed submergence-promoted callus formation in Chinese cabbage(Brassica rapa),indicating that this may be a conserved mechanism in other species.Our study identifies previously unknown regulatory mechanisms by which ethylene promotes cell dedifferentiation and provides a new approach for boosting callus induction efficiency in shoot explants.
