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Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae.
BMC Plant Biol. 2007 Jan 10; 7:2.BP

Abstract

BACKGROUND

A common feature of plant defense responses is the transcriptional regulation of a large number of genes upon pathogen infection or treatment with pathogen elicitors. A large body of evidence suggests that plant WRKY transcription factors are involved in plant defense including transcriptional regulation of plant host genes in response to pathogen infection. However, there is only limited information about the roles of specific WRKY DNA-binding transcription factors in plant defense.

RESULTS

We analyzed the role of the WRKY25 transcription factor from Arabidopsis in plant defense against the bacterial pathogen Pseudomonas syringae. WRKY25 protein recognizes the TTGACC W-box sequences and its translational fusion with green fluorescent protein is localized to the nucleus. WRKY25 expression is responsive to general environmental stress. Analysis of stress-induced WRKY25 in the defense signaling mutants npr1, sid2, ein2 and coi1 further indicated that this gene is positively regulated by the salicylic acid (SA) signaling pathway and negatively regulated by the jasmonic acid signaling pathway. Two independent T-DNA insertion mutants for WRKY25 supported normal growth of a virulent strain of P. syringae but developed reduced disease symptoms after infection. By contrast, Arabidopsis constitutively overexpressing WRKY25 supported enhanced growth of P. syringae and displayed increased disease symptom severity as compared to wild-type plants. These WRKY25-overexpressing plants also displayed reduced expression of the SA-regulated PR1 gene after the pathogen infection, despite normal levels of free SA.

CONCLUSION

The nuclear localization and sequence-specific DNA-binding activity support that WRKY25 functions as a transcription factor. Based on analysis of both T-DNA insertion mutants and transgenic overexpression lines, stress-induced WRKY25 functions as a negative regulator of SA-mediated defense responses to P. syringae. This proposed role is consistent with the recent finding that WRKY25 is a substrate of Arabidopsis MAP kinase 4, a repressor of SA-dependent defense responses.

Authors+Show Affiliations

Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907-2054, USA. zhengz@purdue.edu <zhengz@purdue.edu>No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

17214894

Citation

Zheng, Zuyu, et al. "Functional Analysis of Arabidopsis WRKY25 Transcription Factor in Plant Defense Against Pseudomonas Syringae." BMC Plant Biology, vol. 7, 2007, p. 2.
Zheng Z, Mosher SL, Fan B, et al. Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae. BMC Plant Biol. 2007;7:2.
Zheng, Z., Mosher, S. L., Fan, B., Klessig, D. F., & Chen, Z. (2007). Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae. BMC Plant Biology, 7, 2.
Zheng Z, et al. Functional Analysis of Arabidopsis WRKY25 Transcription Factor in Plant Defense Against Pseudomonas Syringae. BMC Plant Biol. 2007 Jan 10;7:2. PubMed PMID: 17214894.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Functional analysis of Arabidopsis WRKY25 transcription factor in plant defense against Pseudomonas syringae. AU - Zheng,Zuyu, AU - Mosher,Stephen L, AU - Fan,Baofang, AU - Klessig,Daniel F, AU - Chen,Zhixiang, Y1 - 2007/01/10/ PY - 2006/09/15/received PY - 2007/01/10/accepted PY - 2007/1/12/pubmed PY - 2007/3/9/medline PY - 2007/1/12/entrez SP - 2 EP - 2 JF - BMC plant biology JO - BMC Plant Biol VL - 7 N2 - BACKGROUND: A common feature of plant defense responses is the transcriptional regulation of a large number of genes upon pathogen infection or treatment with pathogen elicitors. A large body of evidence suggests that plant WRKY transcription factors are involved in plant defense including transcriptional regulation of plant host genes in response to pathogen infection. However, there is only limited information about the roles of specific WRKY DNA-binding transcription factors in plant defense. RESULTS: We analyzed the role of the WRKY25 transcription factor from Arabidopsis in plant defense against the bacterial pathogen Pseudomonas syringae. WRKY25 protein recognizes the TTGACC W-box sequences and its translational fusion with green fluorescent protein is localized to the nucleus. WRKY25 expression is responsive to general environmental stress. Analysis of stress-induced WRKY25 in the defense signaling mutants npr1, sid2, ein2 and coi1 further indicated that this gene is positively regulated by the salicylic acid (SA) signaling pathway and negatively regulated by the jasmonic acid signaling pathway. Two independent T-DNA insertion mutants for WRKY25 supported normal growth of a virulent strain of P. syringae but developed reduced disease symptoms after infection. By contrast, Arabidopsis constitutively overexpressing WRKY25 supported enhanced growth of P. syringae and displayed increased disease symptom severity as compared to wild-type plants. These WRKY25-overexpressing plants also displayed reduced expression of the SA-regulated PR1 gene after the pathogen infection, despite normal levels of free SA. CONCLUSION: The nuclear localization and sequence-specific DNA-binding activity support that WRKY25 functions as a transcription factor. Based on analysis of both T-DNA insertion mutants and transgenic overexpression lines, stress-induced WRKY25 functions as a negative regulator of SA-mediated defense responses to P. syringae. This proposed role is consistent with the recent finding that WRKY25 is a substrate of Arabidopsis MAP kinase 4, a repressor of SA-dependent defense responses. SN - 1471-2229 UR - https://www.unboundmedicine.com/medline/citation/17214894/Functional_analysis_of_Arabidopsis_WRKY25_transcription_factor_in_plant_defense_against_Pseudomonas_syringae_ L2 - https://bmcplantbiol.biomedcentral.com/articles/10.1186/1471-2229-7-2 DB - PRIME DP - Unbound Medicine ER -