Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully eluci...Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully elucidated. Here, we describe the regulatory control of shoot regeneration in Arabidopsis thaliana(L.) Heynh, based on the interaction of ARABIDOPSIS RESPONSE REGULATOR12(ARR12) and WUSCHEL(WUS). The major site of ARR12 expression coincided with the location where the shoot apical meristem(SAM) initiated. The oar12 mutants showed severely impaired shoot regeneration and reduced responsiveness to cytokinin; consistent with this, the overexpression of ARR12 enhanced shoot regeneration.Certain shoot meristem specification genes, notably WUSCHEL(WUS) and CLAVATA3, were significantly downregulated in the arr1z explants. Chromatin immunoprecipitation(ChIP) and transient activation assays demonstrated that ARR12 binds to the promoter of WUS. These observations indicate that during shoot regeneration, in vitro, ARR12 functions as a molecular link between cytokinin signaling and the expression of shoot meristem specification genes.展开更多
基金financially supported by the National Special Science Research Program of China (grant no.2013CB967300)the National High Technology Research and Development Program "863”(grant no.2013AA102602-4)+2 种基金the National Key Research and Development Program of China (grant no.2016YFD0101902)National Transgenic Project of China (Grant No.2016ZX08010002-002)the National Natural Science Foundation (grant nos.31471515,31500232,31270328,30970243)
文摘Auxin and cytokinin direct cell proliferation and differentiation during the in vitro culture of plant cells, but the molecular basis of these processes, especially de novo shoot regeneration, has not been fully elucidated. Here, we describe the regulatory control of shoot regeneration in Arabidopsis thaliana(L.) Heynh, based on the interaction of ARABIDOPSIS RESPONSE REGULATOR12(ARR12) and WUSCHEL(WUS). The major site of ARR12 expression coincided with the location where the shoot apical meristem(SAM) initiated. The oar12 mutants showed severely impaired shoot regeneration and reduced responsiveness to cytokinin; consistent with this, the overexpression of ARR12 enhanced shoot regeneration.Certain shoot meristem specification genes, notably WUSCHEL(WUS) and CLAVATA3, were significantly downregulated in the arr1z explants. Chromatin immunoprecipitation(ChIP) and transient activation assays demonstrated that ARR12 binds to the promoter of WUS. These observations indicate that during shoot regeneration, in vitro, ARR12 functions as a molecular link between cytokinin signaling and the expression of shoot meristem specification genes.
