J Integr Plant Biol ›› 2017, Vol. 59 ›› Issue (10): 747-758.DOI: 10.1111/jipb.12567

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ARR12 promotes de novo shoot regeneration in Arabidopsis thaliana via activation of WUSCHEL expression

Xuehuan Dai1, Zhenhua Liu1, Meng Qiao2, Juan Li1, Shuo Li1 and Fengning Xiang1*   

  • 收稿日期:2017-05-06 接受日期:2017-07-03 出版日期:2017-10-10 发布日期:2017-07-05

ARR12 promotes de novo shoot regeneration in Arabidopsis thaliana via activation of WUSCHEL expression

Xuehuan Dai1, Zhenhua Liu1, Meng Qiao2, Juan Li1, Shuo Li1 and Fengning Xiang1*   

  1. 1The Key Laboratory of Plant Cell Engineering and Germplasm Innovation, School of Life Sciences, Shandong University, Jinan 250100, China
    2Shandong Province Administration of Work Safety, Jinan 250100, China
  • Received:2017-05-06 Accepted:2017-07-03 Online:2017-10-10 Published:2017-07-05
  • About author:*Correspondence: E-mail: Fengning Xiang (xfn0990@sdu.edu.cn)

摘要： In the arr12 mutant, shoot regeneration was severely impaired and its responsiveness to cytokinin was greatly reduced. ARR12 can directly activate WUS via binding WUS promoter in in vitro culture. Thus ARR12 functions as a link connecting cytokinin signaling with the specification of apical/shoot fate during shoot regeneration.

Abstract:

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 arr12 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 arr12 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.

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