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Two GCC boxes and AP2/ERF-domain transcription factor ORA59 in jasmonate/ethylene-mediated activation of the PDF1.2 promoter in Arabidopsis.

Zarei A, Körbes AP, Younessi P, Montiel G, Champion A, Memelink J - Plant Mol. Biol. (2011)

Bottom Line: Using the chromatin immunoprecipitation technique we were able to show that ORA59 bound the PDF1.2 promoter in vivo.Finally, we show that a tetramer of a single GCC box conferred JA/ethephon-responsive expression, demonstrating that the JA and ET signaling pathways converge to a single type of GCC box.Therefore ORA59 and two functionally equivalent GCC box binding sites form the module that enables the PDF1.2 gene to respond synergistically to simultaneous activation of the JA and ET signaling pathways.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology, Sylvius Laboratory, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands.

ABSTRACT
Plant defense against microbial pathogens depends on the action of several endogenously produced hormones, including jasmonic acid (JA) and ethylene (ET). In defense against necrotrophic pathogens, the JA and ET signaling pathways synergize to activate a specific set of defense genes including PLANT DEFENSIN1.2 (PDF1.2). The APETALA2/Ethylene Response Factor (AP2/ERF)-domain transcription factor ORA59 acts as the integrator of the JA and ET signaling pathways and is the key regulator of JA- and ET-responsive PDF1.2 expression. The present study was aimed at the identification of elements in the PDF1.2 promoter conferring the synergistic response to JA/ET and interacting with ORA59. We show that the PDF1.2 promoter was activated synergistically by JA and the ET-releasing agent ethephon due to the activity of two GCC boxes. ORA59 bound in vitro to these GCC boxes and trans-activated the PDF1.2 promoter in transient assays via these two boxes. Using the chromatin immunoprecipitation technique we were able to show that ORA59 bound the PDF1.2 promoter in vivo. Finally, we show that a tetramer of a single GCC box conferred JA/ethephon-responsive expression, demonstrating that the JA and ET signaling pathways converge to a single type of GCC box. Therefore ORA59 and two functionally equivalent GCC box binding sites form the module that enables the PDF1.2 gene to respond synergistically to simultaneous activation of the JA and ET signaling pathways.

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PDF1.2 promoter constructs. Reporter constructs consisted of the GUS gene driven by wild-type or mutated LF (long fragment −1,187 to +48) or SF (short fragment −278 to +48) PDF1.2 promoter derivatives. Bold and lowercase nucleotides indicate point mutations in GCC boxes. Numbers indicate positions relative to the start site of transcription
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Fig1: PDF1.2 promoter constructs. Reporter constructs consisted of the GUS gene driven by wild-type or mutated LF (long fragment −1,187 to +48) or SF (short fragment −278 to +48) PDF1.2 promoter derivatives. Bold and lowercase nucleotides indicate point mutations in GCC boxes. Numbers indicate positions relative to the start site of transcription

Mentions: PDF1.2 promoter fragments containing 1,187 bp (LF) or 278 bp (SF) upstream of the probable transcription start site (Manners et al. 1998) were fused to the β-glucuronidase (GUS) reporter gene (Fig. 1).Fig. 1


Two GCC boxes and AP2/ERF-domain transcription factor ORA59 in jasmonate/ethylene-mediated activation of the PDF1.2 promoter in Arabidopsis.

Zarei A, Körbes AP, Younessi P, Montiel G, Champion A, Memelink J - Plant Mol. Biol. (2011)

PDF1.2 promoter constructs. Reporter constructs consisted of the GUS gene driven by wild-type or mutated LF (long fragment −1,187 to +48) or SF (short fragment −278 to +48) PDF1.2 promoter derivatives. Bold and lowercase nucleotides indicate point mutations in GCC boxes. Numbers indicate positions relative to the start site of transcription
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3044237&req=5

Fig1: PDF1.2 promoter constructs. Reporter constructs consisted of the GUS gene driven by wild-type or mutated LF (long fragment −1,187 to +48) or SF (short fragment −278 to +48) PDF1.2 promoter derivatives. Bold and lowercase nucleotides indicate point mutations in GCC boxes. Numbers indicate positions relative to the start site of transcription
Mentions: PDF1.2 promoter fragments containing 1,187 bp (LF) or 278 bp (SF) upstream of the probable transcription start site (Manners et al. 1998) were fused to the β-glucuronidase (GUS) reporter gene (Fig. 1).Fig. 1

Bottom Line: Using the chromatin immunoprecipitation technique we were able to show that ORA59 bound the PDF1.2 promoter in vivo.Finally, we show that a tetramer of a single GCC box conferred JA/ethephon-responsive expression, demonstrating that the JA and ET signaling pathways converge to a single type of GCC box.Therefore ORA59 and two functionally equivalent GCC box binding sites form the module that enables the PDF1.2 gene to respond synergistically to simultaneous activation of the JA and ET signaling pathways.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biology, Sylvius Laboratory, Leiden University, P.O. Box 9505, 2300 RA, Leiden, The Netherlands.

ABSTRACT
Plant defense against microbial pathogens depends on the action of several endogenously produced hormones, including jasmonic acid (JA) and ethylene (ET). In defense against necrotrophic pathogens, the JA and ET signaling pathways synergize to activate a specific set of defense genes including PLANT DEFENSIN1.2 (PDF1.2). The APETALA2/Ethylene Response Factor (AP2/ERF)-domain transcription factor ORA59 acts as the integrator of the JA and ET signaling pathways and is the key regulator of JA- and ET-responsive PDF1.2 expression. The present study was aimed at the identification of elements in the PDF1.2 promoter conferring the synergistic response to JA/ET and interacting with ORA59. We show that the PDF1.2 promoter was activated synergistically by JA and the ET-releasing agent ethephon due to the activity of two GCC boxes. ORA59 bound in vitro to these GCC boxes and trans-activated the PDF1.2 promoter in transient assays via these two boxes. Using the chromatin immunoprecipitation technique we were able to show that ORA59 bound the PDF1.2 promoter in vivo. Finally, we show that a tetramer of a single GCC box conferred JA/ethephon-responsive expression, demonstrating that the JA and ET signaling pathways converge to a single type of GCC box. Therefore ORA59 and two functionally equivalent GCC box binding sites form the module that enables the PDF1.2 gene to respond synergistically to simultaneous activation of the JA and ET signaling pathways.

Show MeSH