The Arabidopsis LSD1 gene plays an important role in the regulation of low temperature-dependent cell death.
ABSTRACT SUMMARY: In higher plants, the crosstalk between cold stress responses and reactive oxygen species (ROS) signaling is not well understood. *Two chilling-sensitive mutants, chs4-1 and chs4-3, were characterized genetically and molecularly. *The CHS4 gene, identified by map-based cloning, was found to be identical to lesion simulating disease resistance 1 (LSD1). We therefore renamed these two alleles lsd1-3 and lsd1-4, respectively. These two mutants exhibited an extensive cell death phenotype under cold stress conditions. Consistently, lsd1-3 plants exposed to cold showed up-regulation of the PR1 and PR2 genes, and increased accumulation of salicylic acid. These results indicate that low temperature is another trigger of cell death in lsd1 mutants. Furthermore, lsd1-3 plants accumulated higher concentrations of H(2)O(2) and total glutathione under cold conditions than wild-type plants. Genetic analysis revealed that PAD4 and EDS1, two key signaling regulators mediating resistance responses, are required for the chilling-sensitive phenotype of lsd1-3. *These findings reveal a role of LSD1 in regulating cell death trigged by cold stress and a link between cold stress responses and ROS-associated signaling.
- SourceAvailable from: Sholpan Davletova[show abstract] [hide abstract]
ABSTRACT: Plant acclimation to environmental stress is controlled by a complex network of regulatory genes that compose distinct stress-response regulons. In contrast to many signaling and regulatory genes that are stress specific, the zinc-finger protein Zat12 responds to a large number of biotic and abiotic stresses. Zat12 is thought to be involved in cold and oxidative stress signaling in Arabidopsis (Arabidopsis thaliana); however, its mode of action and regulation are largely unknown. Using a fusion between the Zat12 promoter and the reporter gene luciferase, we demonstrate that Zat12 expression is activated at the transcriptional level during different abiotic stresses and in response to a wound-induced systemic signal. Using Zat12 gain- and loss-of-function lines, we assign a function for Zat12 during oxidative, osmotic, salinity, high light, and heat stresses. Transcriptional profiling of Zat12-overexpressing plants and wild-type plants subjected to H(2)O(2) stress revealed that constitutive expression of Zat12 in Arabidopsis results in the enhanced expression of oxidative- and light stress-response transcripts. Under specific growth conditions, Zat12 may therefore regulate a collection of transcripts involved in the response of Arabidopsis to high light and oxidative stress. Our results suggest that Zat12 plays a central role in reactive oxygen and abiotic stress signaling in Arabidopsis.Plant physiology 11/2005; 139(2):847-56. · 6.56 Impact Factor
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ABSTRACT: To study low-temperature signaling in plants, we previously screened for cold stress response mutants using bioluminescent Arabidopsis plants that express the firefly luciferase reporter gene driven by the stress-responsive RD29A promoter. Here, we report on the characterization and cloning of one mutant, frostbite1 (fro1), which shows reduced luminescence induction by cold. fro1 plants display reduced cold induction of stress-responsive genes such as RD29A, KIN1, COR15A, and COR47. fro1 leaves have a reduced capacity for cold acclimation, appear water-soaked, leak electrolytes, and accumulate reactive oxygen species constitutively. FRO1 was isolated through positional cloning and found to encode a protein with high similarity to the 18-kD Fe-S subunit of complex I (NADH dehydrogenase, EC 18.104.22.168) in the mitochondrial electron transfer chain. Confocal imaging shows that the FRO1:green fluorescent protein fusion protein is localized in mitochondria. These results suggest that cold induction of nuclear gene expression is modulated by mitochondrial function.The Plant Cell 07/2002; 14(6):1235-51. · 9.25 Impact Factor
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ABSTRACT: Systemic acquired resistance (SAR) is a plant immune response induced after a local infection by necrotizing pathogens. The Arabidopsis NPR1 gene is a positive regulator of SAR, essential for transducing the SAR signal salicylic acid (SA). Mutations in the NPR1 gene abolish the SA-induced expression of pathogenesis-related (PR) genes and resistance to pathogens. To identify additional regulators of SAR, we screened for suppressors of npr1-1. In the npr1-1 background, the sni1 (suppressor of npr1-1, inducible 1) mutant shows near wild-type levels of PR1 expression and resistance to pathogens after induction. Restoration of SAR in npr1-1 by the recessive sni1 mutation indicates that wild-type SNI1 may function as a negative regulator of SAR. We cloned the SNI1 gene and found that it encodes a leucine-rich nuclear protein.Cell 09/1999; 98(3):329-39. · 31.96 Impact Factor