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Mol. Cells 2010; 29(1): 71-76

Published online December 10, 2009

https://doi.org/10.1007/s10059-010-0009-z

© The Korean Society for Molecular and Cellular Biology

Non-Specific Phytohormonal Induction of AtMYB44 and Suppression of Jasmonate-Responsive Gene Activation in Arabidopsis thaliana

Choonkyun Jung1,3, Jae Sung Shim1, Jun Sung Seo1, Han Yong Lee1, Chung Ho Kim2, Yang Do Choi1, and Jong-Joo Cheong1,*

1Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea, 2Department of Food and Nutrition, Seowon University, Chongju 361-742, Korea, 3Present address: Laboratory of Plant Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA

Correspondence to : *Correspondence: cheongjj@snu.ac.kr

Received: July 31, 2009; Revised: October 14, 2009; Accepted: October 19, 2009

Abstract

The Arabidopsis thaliana transcription factor gene At-MYB44 was induced within 10 min by treatment with me-thyl jasmonate (MeJA). Wound-induced expression of the gene was observed in local leaves, but not in distal leaves, illustrating jasmonate-independent induction at wound sites. AtMYB44 expression was not abolished in Arabidopsis mutants insensitive to jasmonate (coi1), ethylene (etr1), or abscisic acid (abi3-1) when treated with the corresponding hormones. Moreover, various growth hormones and sugars also induced rapid AtMYB44 transcript accumulation. Thus, AtMYB44 gene activation appears to not be induced by any specific hormone. MeJA-induced activation of jasmonate-responsive genes such as JR2, VSP, LOXII, and AOS was attenuated in transgenic Arabidopsis plants overexpressing the gene (35S:AtMYB44), but significantly enhanced in atmyb44 knockout mutants. The 35S:MYB44 and atmyb44 plants did not show defectiveness in MeJA-induced primary root growth inhibition, indicating that the differences in jasmonate-responsive gene expression observed was not due to alterations in the jasmonate signaling pathway. 35S:AtMYB44 seedlings exhibited slightly elevated chlorophyll levels and less jasmonate-induced anthocyanin accumulation, demonstrating suppression of jasmonate-mediated responses and enhancement of ABA-mediated responses. These observations support the hypothesis of mutual antagonistic actions between jasmonate- and abscisic acid-mediated signaling pathways.

Keywords Arabidopsis, AtMYB44, jasmonate, transcription factor, transgenic plant

Article

Research Article

Mol. Cells 2010; 29(1): 71-76

Published online January 31, 2010 https://doi.org/10.1007/s10059-010-0009-z

Copyright © The Korean Society for Molecular and Cellular Biology.

Non-Specific Phytohormonal Induction of AtMYB44 and Suppression of Jasmonate-Responsive Gene Activation in Arabidopsis thaliana

Choonkyun Jung1,3, Jae Sung Shim1, Jun Sung Seo1, Han Yong Lee1, Chung Ho Kim2, Yang Do Choi1, and Jong-Joo Cheong1,*

1Department of Agricultural Biotechnology and Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, Korea, 2Department of Food and Nutrition, Seowon University, Chongju 361-742, Korea, 3Present address: Laboratory of Plant Molecular Biology, The Rockefeller University, 1230 York Avenue, New York, NY 10065, USA

Correspondence to:*Correspondence: cheongjj@snu.ac.kr

Received: July 31, 2009; Revised: October 14, 2009; Accepted: October 19, 2009

Abstract

The Arabidopsis thaliana transcription factor gene At-MYB44 was induced within 10 min by treatment with me-thyl jasmonate (MeJA). Wound-induced expression of the gene was observed in local leaves, but not in distal leaves, illustrating jasmonate-independent induction at wound sites. AtMYB44 expression was not abolished in Arabidopsis mutants insensitive to jasmonate (coi1), ethylene (etr1), or abscisic acid (abi3-1) when treated with the corresponding hormones. Moreover, various growth hormones and sugars also induced rapid AtMYB44 transcript accumulation. Thus, AtMYB44 gene activation appears to not be induced by any specific hormone. MeJA-induced activation of jasmonate-responsive genes such as JR2, VSP, LOXII, and AOS was attenuated in transgenic Arabidopsis plants overexpressing the gene (35S:AtMYB44), but significantly enhanced in atmyb44 knockout mutants. The 35S:MYB44 and atmyb44 plants did not show defectiveness in MeJA-induced primary root growth inhibition, indicating that the differences in jasmonate-responsive gene expression observed was not due to alterations in the jasmonate signaling pathway. 35S:AtMYB44 seedlings exhibited slightly elevated chlorophyll levels and less jasmonate-induced anthocyanin accumulation, demonstrating suppression of jasmonate-mediated responses and enhancement of ABA-mediated responses. These observations support the hypothesis of mutual antagonistic actions between jasmonate- and abscisic acid-mediated signaling pathways.

Keywords: Arabidopsis, AtMYB44, jasmonate, transcription factor, transgenic plant

Mol. Cells
Nov 30, 2023 Vol.46 No.11, pp. 655~725
COVER PICTURE
Kim et al. (pp. 710-724) demonstrated that a pathogen-derived Ralstonia pseudosolanacearum type III effector RipL delays flowering time and enhances susceptibility to bacterial infection in Arabidopsis thaliana. Shown is the RipL-expressing Arabidopsis plant, which displays general dampening of the transcriptional program during pathogen infection, grown in long-day conditions.

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