J Integr Plant Biol. ›› 2021, Vol. 63 ›› Issue (8): 1491-1504.DOI: 10.1111/jipb.13156

Special Issue: Epigenetics

• Cell and Developmental Biology • Previous Articles     Next Articles

Cytosine methylation of the FWA promoter promotes direct in vitro shoot regeneration in Arabidopsis thaliana

Xuehuan Dai1†, Jing Wang1†, Yuguang Song1,2†, Zhenhua Liu1,3, Tao Xue1,4, Meng Qiao1, Yanchong Yu1,5, Wei Xin1,6 and Fengning Xiang1*   

  1. 1 The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao 266237, China
    2 Present address: Qufu Normal University, Qufu 273165, China
    3 Present address: Shandong University of Traditional Chinese Medicine, Jinan 250355, China
    4 Present address: Huaibei Normal University, Huaibei 235000, China
    5 Present address: Qingdao Agricultural University, Qingdao 266109, China
    6 Present address: Institute of Botany, The Chinese Academy of Sciences, Beijing 100101, China

    These authors contributed equally to this work.
    *Correspondence: Fengning Xiang (xfn0990@sdu.edu.cn)
  • Received:2021-02-24 Accepted:2021-07-20 Online:2021-07-22 Published:2021-08-01

Abstract: Epigenetic modifications within promoter sequences can act as regulators of gene expression. Shoot regeneration is influenced by both DNA methylation and histone methylation, but the mechanistic basis of this regulation is obscure. Here, we identified 218 genes related to the regeneration capacity of callus that were differentially transcribed between regenerable calli (RC) and non-regenerable calli (NRC) in Arabidopsis thaliana. An analysis of the promoters of five of the differentially expressed genes (FWA, ACC1, TFL1, MAX3, and GRP3) pointed to an inverse relationship between cytosine methylation and transcription. The FWA promoter was demethylated and highly expressed in NRC, whereas it was methylated and expressed at low levels in RC. Explants of the hypomethylation mutants fwa-1 and fwa-2 showed strong levels of FWA expression and regenerated less readily than the wild type, suggesting that FWA inhibits direct in vitro shoot regeneration. WUSCHEL-RELATED HOMEOBOX 9 (WOX9), which is required for shoot apical meristem formation, was directly repressed by FWA. Overexpressing WOX9 partly rescued the shoot regeneration defect of fwa-2 plants. These findings suggest that cytosine methylation of the FWA promoter forms part of the regulatory system governing callus regenerability and direct in vitro shoot regeneration.

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