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This content will become publicly available on February 2, 2017

Title: Spatially and temporally restricted expression of PtrMYB021 regulates secondary cell wall formation in Arabidopsis

Among the R2R3 MYB transcription factors that involve in the regulation of secondary cell wall formation in Arabidopsis, MYB46 alone is sufficient to induce the entire secondary cell wall biosynthesis program. PtrMYB021, the poplar homolog of MYB46, has been reported to regulate secondary cell wall formation when expressed in Arabidopsis. We report here that spatially and temporally restricted expression of PtrMYB021 is critical for its function in regulating secondary cell wall formation. By using quantitative RT-PCR, we found that PtrMYB021 was expressed primarily in xylem tissues. When expressed in Arabidopsis under the control of PtrCesA8, but not the 35S promoter, PtrMYB021 increased secondary cell wall thickness, which is likely caused by increased lignification as well as changes in cell wall carbohydrate composition. Consistent with this, elevated expression of lignin and cellulose biosynthetic genes were observed in the transgenic plants. Finally, when expressed in Arabidopsis protoplasts as fusion proteins to the Gal4 DNA binding domain, PtrMYB021 activated the reporter gene Gal4-GUS. In summary, our results suggest that PtrMYB021 is a transcriptional activator, and spatially and temporally restricted expression of PtrMYB021 in Arabidopsis regulates secondary cell wall formation by activating a subset of secondary cell wall biosynthesis genes.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [3] ;  [2] ;  [1]
  1. Northeast Normal Univ. Changchun (China). Key Lab. of Molecular Epigenetics of MOE
  2. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Botany
  3. Univ. of British Columbia, Vancouver, BC (Canada). Dept. of Wood Science
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Biosciences Division
Publication Date:
OSTI Identifier:
1319199
Grant/Contract Number:
AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Journal of Plant Biology
Additional Journal Information:
Journal Volume: 59; Journal Issue: 1; Journal ID: ISSN 1226-9239
Publisher:
Springer
Research Org:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE; Northeast Normal University; Genome British Columbia Applied Genomics Innovation Program
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES Arabidopsis thaliana; Populus trichocarpa; PtrMYB021; R2R3 MYB; Secondary cell wall biosynthesis; Transcription factor