Rice OVATE family protein 6 regulates leaf angle by modulating secondary cell wall biosynthesis

Plant Mol Biol. 2020 Oct;104(3):249-261. doi: 10.1007/s11103-020-01039-2. Epub 2020 Jul 26.


Secondary cell wall not only provides rigidity and mechanical resistance to plants, but also has a large impact on plant growth and adaptation to environments. Biosynthesis of secondary cell wall is regulated by a complicated signaling transduction network; however, it is still unclear how the transcriptional regulation of secondary cell wall biosynthesis works at the molecular level. Here, we report in rice that OVATE family proteins 6 (OsOFP6) is a positive regulator in modulating expression of the genes related to biosynthesis of the secondary cell wall. Transgenic plants with knock-down of OsOFP6 by RNA interference showed increased leaf angle, which resulted from the thinner secondary cell wall with reduced amounts of cellulose and lignin, whilst overexpression of OsOFP6 in rice led to the thinker secondary cell wall with increased lignin content. Protein-protein interaction analysis revealed that OsOFP6 interacts with Oryza sativa homeobox 15 (OSH15), a class I KNOX protein. The interaction of OsOFP6 and OSH15 enhanced the transcriptional activity of OSH15 which binds to the promoter of OsIRX9 (Oryza sativa IRREGULAR XYLEM 9). Taken together, our study provides insights into the function of OsOFP6 in regulating leaf angle and the control of biosynthesis of secondary cell wall.

Keywords: Leaf angle; Mechanical strength; OVATE protein; Rice; Secondary cell wall; Xylan.

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis Proteins / genetics
  • Cell Wall / metabolism*
  • Cell Wall / ultrastructure
  • Cellulose / metabolism
  • Gene Expression Regulation, Plant
  • Homeodomain Proteins / metabolism
  • Lignin / metabolism
  • Oryza / genetics
  • Oryza / metabolism*
  • Plant Leaves / anatomy & histology
  • Plant Leaves / cytology
  • Plant Leaves / metabolism*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Plants, Genetically Modified / genetics
  • Promoter Regions, Genetic
  • Protein Interaction Domains and Motifs
  • RNA Interference
  • Repressor Proteins / genetics
  • Repressor Proteins / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Xylem / metabolism


  • Arabidopsis Proteins
  • Homeodomain Proteins
  • OSH15 protein, Oryza sativa
  • Plant Proteins
  • Repressor Proteins
  • Transcription Factors
  • ovate family protein 1, Arabidopsis
  • Cellulose
  • Lignin