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Gene Review

NPR1  -  Regulatory protein NPR1

Arabidopsis thaliana

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Disease relevance of NPR1


High impact information on NPR1

  • These data provide a missing link between accumulation of SA and activation of NPR1 in the SAR signaling pathway [5].
  • SAR induction results in accumulation of the signal molecule salicylic acid (SA), which induces defense gene expression via activation of NPR1 [5].
  • The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats [6].
  • The lesion in one npr1 mutant allele disrupted the ankyrin consensus sequence, suggesting that these repeats are important for NPR1 function [6].
  • On the other hand, WRKY6 positively influenced the senescence- and pathogen defense-associated PR1 promoter activity, most likely involving NPR1 function [7].

Biological context of NPR1


Anatomical context of NPR1

  • NPR1 modulates cross-talk between salicylate- and jasmonate-dependent defense pathways through a novel function in the cytosol [11].
  • Interestingly, however, FB1-induced PCD does not require the SA signal transmitter NPR1, given that npr1-1 protoplasts display wild-type FB1 susceptibility [12].
  • Because the levels of plastid complex lipid species containing hexadecatrienoic acid are depressed in all of the sfd ssi2 npr1 plants, we propose that these lipids are involved in the manifestation of the ssi2-conferred phenotypes [13].

Associations of NPR1 with chemical compounds

  • We are systematically investigating the role of individual TGA factors in the transcriptional control of pathogenesis-related (PR) defense genes, whose expression is stimulated in leaves by salicylic acid (SA) through a stimulus pathway involving NPR1 [14].
  • Hence, we postulate that rhizobacteria-mediated ISR follows a novel signaling pathway in which components from the jasmonate and ethylene response are engaged successively to trigger a defense reaction that, like SAR, is regulated by NPR1 [15].
  • To gain a better understanding of NPR1 function, we conducted a yeast two-hybrid screening procedure and identified a differential interaction between NPR1 and all known members of the Arabidopsis TGA family of basic leucine zipper transcription factors [16].
  • A mutation in the Arabidopsis gene ssi2/fab2, which encodes stearoyl-acyl carrier protein desaturase (S-ACP-DES), results in the reduction of oleic acid (18:1) levels in the mutant plants and also leads to the constitutive activation of NPR1-dependent and -independent defense responses [17].
  • These results suggest that the ozone-induced expression of FAD7 gene requires SA, but not ethylene, JA, NPR1 and SID2 [18].

Physical interactions of NPR1


Regulatory relationships of NPR1


Other interactions of NPR1


Analytical, diagnostic and therapeutic context of NPR1

  • The relevance of these findings to PR-1 expression was investigated by the use of chromatin immunoprecipitation, which demonstrated that in vivo these TGA factors are strongly recruited in an SA- and NPR1-dependent manner to the LS7-containing PR-1 promoter [14].
  • In the electrophoretic mobility shift assay, NPR1 substantially increased the binding of TGA2 to its cognate promoter element (as-1) as well as to a positive salicylic acid-inducible element (LS7) and a negative element (LS5) in the promoter of the pathogenesis-related PR-1 gene [16].
  • Here, we report the identification of another component, CPR 6, that may function with NPR1 in regulating PR gene expression [26].
  • Furthermore, site-directed mutagenesis of TGA1 Cys-260 and Cys-266 enables the interaction with NPR1 in yeast and Arabidopsis [19].
  • However, the SA signal transducer NPR1 was required only for constitutive PR-1 expression [27].


  1. Evidence for a disease-resistance pathway in rice similar to the NPR1-mediated signaling pathway in Arabidopsis. Chern, M.S., Fitzgerald, H.A., Yadav, R.C., Canlas, P.E., Dong, X., Ronald, P.C. Plant J. (2001) [Pubmed]
  2. Ethylene and jasmonic acid signaling affect the NPR1-independent expression of defense genes without impacting resistance to Pseudomonas syringae and Peronospora parasitica in the Arabidopsis ssi1 mutant. Nandi, A., Kachroo, P., Fukushige, H., Hildebrand, D.F., Klessig, D.F., Shah, J. Mol. Plant Microbe Interact. (2003) [Pubmed]
  3. Plant growth-promoting rhizobacteria systemically protect Arabidopsis thaliana against Cucumber mosaic virus by a salicylic acid and NPR1-independent and jasmonic acid-dependent signaling pathway. Ryu, C.M., Murphy, J.F., Mysore, K.S., Kloepper, J.W. Plant J. (2004) [Pubmed]
  4. Transgenic tomato plants expressing the Arabidopsis NPR1 gene display enhanced resistance to a spectrum of fungal and bacterial diseases. Lin, W.C., Lu, C.F., Wu, J.W., Cheng, M.L., Lin, Y.M., Yang, N.S., Black, L., Green, S.K., Wang, J.F., Cheng, C.P. Transgenic Res. (2004) [Pubmed]
  5. Inducers of plant systemic acquired resistance regulate NPR1 function through redox changes. Mou, Z., Fan, W., Dong, X. Cell (2003) [Pubmed]
  6. The Arabidopsis NPR1 gene that controls systemic acquired resistance encodes a novel protein containing ankyrin repeats. Cao, H., Glazebrook, J., Clarke, J.D., Volko, S., Dong, X. Cell (1997) [Pubmed]
  7. Targets of AtWRKY6 regulation during plant senescence and pathogen defense. Robatzek, S., Somssich, I.E. Genes Dev. (2002) [Pubmed]
  8. In vivo interaction between NPR1 and transcription factor TGA2 leads to salicylic acid-mediated gene activation in Arabidopsis. Fan, W., Dong, X. Plant Cell (2002) [Pubmed]
  9. Interaction of NIMIN1 with NPR1 modulates PR gene expression in Arabidopsis. Weigel, R.R., Pfitzner, U.M., Gatz, C. Plant Cell (2005) [Pubmed]
  10. Negative regulation of defense responses in Arabidopsis by two NPR1 paralogs. Zhang, Y., Cheng, Y.T., Qu, N., Zhao, Q., Bi, D., Li, X. Plant J. (2006) [Pubmed]
  11. NPR1 modulates cross-talk between salicylate- and jasmonate-dependent defense pathways through a novel function in the cytosol. Spoel, S.H., Koornneef, A., Claessens, S.M., Korzelius, J.P., Van Pelt, J.A., Mueller, M.J., Buchala, A.J., Métraux, J.P., Brown, R., Kazan, K., Van Loon, L.C., Dong, X., Pieterse, C.M. Plant Cell (2003) [Pubmed]
  12. Fumonisin B1-induced cell death in arabidopsis protoplasts requires jasmonate-, ethylene-, and salicylate-dependent signaling pathways. Asai, T., Stone, J.M., Heard, J.E., Kovtun, Y., Yorgey, P., Sheen, J., Ausubel, F.M. Plant Cell (2000) [Pubmed]
  13. Arabidopsis sfd mutants affect plastidic lipid composition and suppress dwarfing, cell death, and the enhanced disease resistance phenotypes resulting from the deficiency of a fatty acid desaturase. Nandi, A., Krothapalli, K., Buseman, C.M., Li, M., Welti, R., Enyedi, A., Shah, J. Plant Cell (2003) [Pubmed]
  14. Salicylic acid and NPR1 induce the recruitment of trans-activating TGA factors to a defense gene promoter in Arabidopsis. Johnson, C., Boden, E., Arias, J. Plant Cell (2003) [Pubmed]
  15. A novel signaling pathway controlling induced systemic resistance in Arabidopsis. Pieterse, C.M., van Wees, S.C., van Pelt, J.A., Knoester, M., Laan, R., Gerrits, H., Weisbeek, P.J., van Loon, L.C. Plant Cell (1998) [Pubmed]
  16. The Arabidopsis NPR1/NIM1 protein enhances the DNA binding activity of a subgroup of the TGA family of bZIP transcription factors. Després, C., DeLong, C., Glaze, S., Liu, E., Fobert, P.R. Plant Cell (2000) [Pubmed]
  17. Plastidial fatty acid signaling modulates salicylic acid- and jasmonic acid-mediated defense pathways in the Arabidopsis ssi2 mutant. Kachroo, A., Lapchyk, L., Fukushige, H., Hildebrand, D., Klessig, D., Kachroo, P. Plant Cell (2003) [Pubmed]
  18. Ozone-induced Expression of the Arabidopsis FAD7 Gene Requires Salicylic Acid, but not NPR1 and SID2. Yaeno, T., Saito, B., Katsuki, T., Iba, K. Plant Cell Physiol. (2006) [Pubmed]
  19. The Arabidopsis NPR1 disease resistance protein is a novel cofactor that confers redox regulation of DNA binding activity to the basic domain/leucine zipper transcription factor TGA1. Després, C., Chubak, C., Rochon, A., Clark, R., Bethune, T., Desveaux, D., Fobert, P.R. Plant Cell (2003) [Pubmed]
  20. The cpr5 mutant of Arabidopsis expresses both NPR1-dependent and NPR1-independent resistance. Bowling, S.A., Clarke, J.D., Liu, Y., Klessig, D.F., Dong, X. Plant Cell (1997) [Pubmed]
  21. Potentiation of developmentally regulated plant defense response by AtWRKY18, a pathogen-induced Arabidopsis transcription factor. Chen, C., Chen, Z. Plant Physiol. (2002) [Pubmed]
  22. Genetically engineered resistance to Fusarium head blight in wheat by expression of Arabidopsis NPR1. Makandar, R., Essig, J.S., Schapaugh, M.A., Trick, H.N., Shah, J. Mol. Plant Microbe Interact. (2006) [Pubmed]
  23. Knockout analysis of Arabidopsis transcription factors TGA2, TGA5, and TGA6 reveals their redundant and essential roles in systemic acquired resistance. Zhang, Y., Tessaro, M.J., Lassner, M., Li, X. Plant Cell (2003) [Pubmed]
  24. Major signaling pathways modulate Arabidopsis glucosinolate accumulation and response to both phloem-feeding and chewing insects. Mewis, I., Appel, H.M., Hom, A., Raina, R., Schultz, J.C. Plant Physiol. (2005) [Pubmed]
  25. Salicylic acid-mediated cell death in the Arabidopsis len3 mutant. Ishikawa, A., Kimura, Y., Yasuda, M., Nakashita, H., Yoshida, S. Biosci. Biotechnol. Biochem. (2006) [Pubmed]
  26. Uncoupling PR gene expression from NPR1 and bacterial resistance: characterization of the dominant Arabidopsis cpr6-1 mutant. Clarke, J.D., Liu, Y., Klessig, D.F., Dong, X. Plant Cell (1998) [Pubmed]
  27. Environmentally sensitive, SA-dependent defense responses in the cpr22 mutant of Arabidopsis. Yoshioka, K., Kachroo, P., Tsui, F., Sharma, S.B., Shah, J., Klessig, D.F. Plant J. (2001) [Pubmed]
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