J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (5): 1134-1146.DOI: 10.1111/jipb.13453

• Cell and Developmental Biology • Previous Articles     Next Articles

PagERF81 regulates lignin biosynthesis and xylem cell differentiation in poplar

Xin‐Wei Zhao1,2, Qiao Wang2, Dian Wang3, Wei Guo4, Meng‐Xuan Hu1, Ying‐Li Liu1, Gong‐Ke Zhou5, Guo‐Hua Chai2, Shu‐Tang Zhao1* and Meng‐Zhu Lu1,6*   

  1. 1. State Key Laboratory of Tree Genetics and Breeding, Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China;
    2. College of Resources and Environment, Qingdao Agricultural University, Qingdao 266109, China;
    3. College of Agronomy, Qingdao Agricultural University, Qingdao 266109, China;
    4. Taishan Academy of Forestry Sciences, Taian 271000, China;
    5. College of Landscape Architecture and Forestry, Qingdao Agricultural University, Qingdao 266109, China;
    6. State Key Laboratory of Subtropical Silviculture, College of Forestry and Biotechnology, Zhejiang A & F University, Hangzhou 311300, China
    *Correspondences: Meng‐Zhu Lu (lumz@caf.ac.cn); Shu‐Tang Zhao (shutang@caf.ac.cn, Dr. Zhao is fully responsible for the distribution of all materials associated with this article)
  • Received:2022-08-29 Accepted:2023-01-15 Online:2023-03-15 Published:2023-05-01

Abstract: Lignin is a major component of plant cell walls and is essential for plant growth and development. Lignin biosynthesis is controlled by a hierarchical regulatory network involving multiple transcription factors. In this study, we showed that the gene encoding an APETALA 2/ethylene-responsive element binding factor (AP2/ERF) transcription factor, PagERF81, from poplar 84?K (Populus alba × P. glandulosa) is highly expressed in expanding secondary xylem cells. Two independent homozygous Pagerf81 mutant lines created by gene editing, produced significantly more but smaller vessel cells and longer fiber cells with more lignin in cell walls, while PagERF81 overexpression lines had less lignin, compared to non-transgenic controls. Transcriptome and reverse transcription quantitative PCR data revealed that multiple lignin biosynthesis genes including Cinnamoyl CoA reductase 1 (PagCCR1), Cinnamyl alcohol dehydrogenase 6 (PagCAD6), and 4-Coumarate-CoA ligase-like 9 (Pag4CLL9) were up-regulated in Pagerf81 mutants, but down-regulated in PagERF81 overexpression lines. In addition, a transient transactivation assay revealed that PagERF81 repressed the transcription of these three genes. Furthermore, yeast one hybrid and electrophoretic mobility shift assays showed that PagERF81 directly bound to a GCC sequence in the PagCCR1 promoter. No known vessel or fiber cell differentiation related genes were differentially expressed, so the smaller vessel cells and longer fiber cells observed in the Pagerf81 lines might be caused by abnormal lignin deposition in the secondary cell walls. This study provides insight into the regulation of lignin biosynthesis, and a molecular tool to engineer wood with high lignin content, which would contribute to the lignin-related chemical industry and carbon sequestration.

Key words: lignin biosynthesis, PagERF81, Populus, secondary cell wall, xylem development

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