Biomaterial Database

Nuclear localization of NPR1 is required for regulation of salicylate tolerance, isochorismate synthase 1 expression and salicylate accumulation in Arabidopsis. 2010

Xudong Zhang, and Sixue Chen, and Zhonglin Mou

Department of Microbiology and Cell Science, University of Florida, P.O. Box 110700, Gainesville, FL 32611, USA.

Plant systemic acquired resistance (SAR) is a broad-spectrum immune response in which pathogen infection in local tissue induces resistance in systemic leaves. Activation of SAR requires the signal molecule salicylic acid (SA), which is primarily synthesized from chorismate via isochorismate through the action of isochorismate synthase 1 (ICS1) and a putative isochorismate pyruvate lyase. The Arabidopsis transcription coactivator NPR1 is a key regulator of SAR, which functions at multiple nodes in the SA signaling network. NPR1 not only acts downstream of SA to activate SAR, but also upstream of SA to suppress the expression of ICS1, thus inhibiting SA biosynthesis. NPR1 also positively regulates SA tolerance and plays a role in SA-mediated negative regulation of jasmonic acid (JA) signaling. The NPR1 protein contains a functional bipartite nuclear localization signal (NLS). It has been shown that the NLS and nuclear localization of NPR1 are required for activation of pathogenesis-related gene expression, whereas modulation of the crosstalk between SA- and JA-dependent defense pathways is mediated by cytosolic NPR1. In this study we used two transgenic lines, one expressing a mutated npr1 with a dysfunctional NLS and the other in which NPR1 nuclear localization can be induced by dexamethasone treatment, to test whether nuclear localization is required for other functions of NPR1. We found that prevention of NPR1 nuclear localization renders transgenic seedlings sensitive to the toxicity of high levels of SA and causes over-accumulation of ICS1 transcripts and SA in response to pathogen infection. Induction of NPR1 nuclear localization restores SA tolerance and normal accumulation of ICS1 transcripts and SA. These results indicate that the NLS and nuclear localization of NPR1 are required for regulation of SA tolerance, ICS1 expression and SA accumulation.

UI	MeSH Term	Description	Entries
D002467	Cell Nucleus	Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)	Cell Nuclei,Nuclei, Cell,Nucleus, Cell
D012459	Salicylates	The salts or esters of salicylic acids, or salicylate esters of an organic acid. Some of these have analgesic, antipyretic, and anti-inflammatory activities by inhibiting prostaglandin synthesis.	Salicylate,Salicylic Acids,Acids, Salicylic
D017360	Arabidopsis	A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.	Arabidopsis thaliana,Cress, Mouse-ear,A. thaliana,A. thalianas,Arabidopses,Arabidopsis thalianas,Cress, Mouse ear,Cresses, Mouse-ear,Mouse-ear Cress,Mouse-ear Cresses,thaliana, A.,thaliana, Arabidopsis,thalianas, A.
D044224	Pseudomonas syringae	A species of gram-negative, fluorescent, phytopathogenic bacteria in the genus PSEUDOMONAS. It is differentiated into approximately 50 pathovars with different plant pathogenicities and host specificities.	Pseudomonas syringae subsp. syringae
D019751	Intramolecular Transferases	Enzymes of the isomerase class that catalyze the transfer of acyl-, phospho-, amino- or other groups from one position within a molecule to another. EC 5.4.	Mutases,Transferases, Intramolecular
D020133	Reverse Transcriptase Polymerase Chain Reaction	A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.	Polymerase Chain Reaction, Reverse Transcriptase,Reverse Transcriptase PCR,PCR, Reverse Transcriptase,Transcriptase PCR, Reverse
D029681	Arabidopsis Proteins	Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.	Arabidopsis thaliana Proteins,Thale Cress Proteins,Proteins, Arabidopsis thaliana,thaliana Proteins, Arabidopsis
D030821	Plants, Genetically Modified	PLANTS, or their progeny, whose GENOME has been altered by GENETIC ENGINEERING.	Genetically Modified Plants,Plants, Transgenic,Transgenic Plants,GMO Plants,Genetically Engineered Plants,Engineered Plant, Genetically,Engineered Plants, Genetically,GMO Plant,Genetically Engineered Plant,Genetically Modified Plant,Modified Plant, Genetically,Modified Plants, Genetically,Plant, GMO,Plant, Genetically Engineered,Plant, Genetically Modified,Plant, Transgenic,Plants, GMO,Plants, Genetically Engineered,Transgenic Plant