Journal article
A lesion-mimic syntaxin double mutant in Arabidopsis reveals novel complexity of pathogen defense signaling
Plant and Soil Science, Dept of Agricultural Sciences, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.1
The lesion-mimic Arabidopsis mutant, syp121 syp122, constitutively expresses the salicylic acid (SA) signaling pathway and has low penetration resistance to powdery mildew fungi. Genetic analyses of the lesion-mimic phenotype have expanded our understanding of programmed cell death (PCD) in plants. Inactivation of SA signaling genes in syp121 syp122 only partially rescues the lesion-mimic phenotype, indicating that additional defenses contribute to the PCD.
Whole genome transcriptome analysis confirmed that SA-induced transcripts, as well as numerous other known pathogen-response transcripts, are up-regulated after inactivation of the syntaxin genes. A suppressor mutant analysis of syp121 syp122 revealed that FMO1, ALD1, and PAD4 are important for lesion development.
Mutant alleles of EDS1, NDR1, RAR1, and SGT1b also partially rescued the lesion-mimic phenotype, suggesting that mutating syntaxin genes stimulates TIR-NB-LRR and CC-NB-LRR-type resistances. The syntaxin double knockout potentiated a powdery mildew-induced HR-like response. This required functional PAD4 but not functional SA signaling.
However, SA signaling potentiated the PAD4-dependent HR-like response. Analyses of quadruple mutants suggest that EDS5 and SID2 confer separate SA-independent signaling functions, and that FMO1 and ALD1 mediate SA-independent signals that are NPR1-dependent. These studies highlight the contribution of multiple pathways to defense and point to the complexity of their interactions.
Language: | English |
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Publisher: | Elsevier BV |
Year: | 2008 |
Pages: | 510-27 |
ISSN: | 17529867 and 16742052 |
Types: | Journal article |
DOI: | 10.1093/mp/ssn011 |
ORCIDs: | Lenk, Andrea , Pedersen, Carsten , Newman, Mari-Anne and Thordal-Christensen, Hans |
AGD2-LIKE DEFENSE RESPONSE PROTEIN1, Arabidopsis Arabidopsis Arabidopsis Proteins Carboxylic Ester Hydrolases Carrier Proteins Cell Cycle Proteins Cyclopentanes DNA-Binding Proteins EDS1 protein, Arabidopsis Gene Expression Profiling Genetic Variation Intracellular Signaling Peptides and Proteins Mutation NDR1 protein, Arabidopsis Oxylipins PAD4 protein, Arabidopsis PBS2 protein, Arabidopsis PEN1 protein, Arabidopsis Phenotype Plant Diseases Qa-SNARE Proteins SGT1b protein, Arabidopsis Signal Transduction Transaminases Transcription Factors Transcription, Genetic jasmonic acid