The NPR1 homolog GhNPR1 plays an important role in the defense response of Gladiolus hybridus
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GhNPR1 shares similar functions as Arabidopsis NPR1 . Silencing of GhNPR1 in Gladiolus results in an enhanced susceptibility to Curvularia gladioli. We propose that GhNPR1 plays important roles in plant immunity.
Gladiolus plants and corms are susceptible to various types of pathogens including fungi, bacteria and viruses. Understanding the innate defense mechanism in Gladiolus is a prerequisite for the development of new protection strategies. The non-expressor of pathogenesis-related gene 1 (NPR1) and bzip transcription factor TGA2 play a key role in regulating salicylic acid (SA)-mediated systemic acquired resistance (SAR). In this study, the homologous genes, GhNPR1 and GhTGA2, were isolated from Gladiolus and functionally characterized. Expression of GhNPR1 exhibited a 3.8-fold increase in Gladiolus leaves following salicylic acid treatment. A 1332 bp fragment of the GhNPR1 promoter from Gladiolus hybridus was identified. Inducibility of the GhNPR1 promoter by SA was demonstrated using transient expression assays in the leaves of Nicotiana benthamiana. The GhNPR1 protein is located in the nucleus and cytomembrane. GhNPR1 interacts with GhTGA2, as observed using the bimolecular fluorescence complementation system. Overexpression of GhNPR1 in an Arabidopsis npr1 mutant can restore its basal resistance to Pseudomonas syringae pv. tomato DC3000. Silencing of GhNPR1, using a tobacco rattle virus-based silencing vector, resulted in an enhanced susceptibility to Curvularia gladioli. In conclusion, these results suggest that GhNPR1 plays a pivotal role in the SA-dependent systemic acquired resistance in Gladiolus.
KeywordsDisease resistance Fungal diseases Gladiolus Salicylic acid Systemic acquired resistance
This study has been supported by the Science and Technology Specific Project Foundation of Ministry of Agriculture, PR China (No. 200903020), National Natural Science Foundation of China (No. 31171991) and Chinese Universities Scientific Fund (No. 15053201 and No. 15054201).
Conflict of interest
The authors declare that they have no conflicts of interest.
- Baiswar P, Chandra S, Kumar R (2007) Status of gladiolus diseases and their management in India-A review. J Ornam Hortic 10(4):209–214Google Scholar
- Barsalobres Cavallari C, Petitot A, Severino F, Maia I, Fernandez D (2013) Host response profiling to fungal infection: molecular cloning, characterization and expression analysis of NPR1 gene from coffee (Coffea arabica). Microbial pathogens and strategies for combating them: science, technology and education, vol 1. Formatex Research Center, BadajozGoogle Scholar
- Benschop M, Kamenetsky R, Le Nard M, Okubo H, De Hertogh A (2010) The global flower bulb industry: production, utilization, research. Acta Physiol Plant 36:1Google Scholar
- Després C, Chubak C, Rochon A, Clark R, Bethune T, Desveaux D, Fobert PR (2003) 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. Plant Cell 15(9):2181–2191CrossRefPubMedCentralPubMedGoogle Scholar
- Giri MK, Swain S, Gautam JK, Singh S, Singh N, Bhattacharjee L, Nandi AK (2014) The Arabidopsis thaliana At4g13040 gene, a unique member of the AP2/EREBP family, is a positive regulator for salicylic acid accumulation and basal defense against bacterial pathogens. J Plant Physiol 171(10):860–867CrossRefPubMedGoogle Scholar
- Koschmann J, Machens F, Becker M, Niemeyer J, Schulze J, Bülow L, Stahl DJ, Hehl R (2012) Integration of bioinformatics and synthetic promoters leads to the discovery of novel elicitor-responsive cis-regulatory sequences in Arabidopsis. Plant Physiol 160(1):178–191CrossRefPubMedCentralPubMedGoogle Scholar
- Le Henanff G, Farine S, Kieffer Mazet F, Miclot AS, Heitz T, Mestre P, Bertsch C, Chong JL (2011) Vitis vinifera VvNPR1. 1 is the functional ortholog of AtNPR1 and its overexpression in grapevine triggers constitutive activation of PR genes and enhanced resistance to powdery mildew. Planta 234(2):405–417CrossRefPubMedGoogle Scholar
- Magie R (1948) Curvularia spot, a new disease of gladiolus. Plant Dis Rep 32:11–13Google Scholar
- Prestridge DS (1991) SIGNAL SCAN: a computer program that scans DNA sequences for eukaryotic transcriptional elements. Comput Appl Biosci CABIOS 7(2):203–206Google Scholar
- Timmermans A (1942) Botrytis gladiolorum n. sp., the agent of the Botrytis rot of Gladioli. Nederlandsch kruidkd Archief 52:59–64Google Scholar
- Zhang M, Wu HY, Tian ZQ, Zhang TY (2006) Three new records of Curvularia in China. J Henan Agric Univ 40(5):524–526Google Scholar
- Zhou JM, Trifa Y, Silva H, Pontier D, Lam E, Shah J, Klessig DF (2000) NPR1 differentially interacts with members of the TGA/OBF family of transcription factors that bind an element of the PR-1 gene required for induction by salicylic acid. Mol Plant Microbe Interact 13(2):191–202CrossRefPubMedGoogle Scholar