Vogelmann, Katja and Drechsel, Gabriele and Bergler, Johannes and Subert, Christa and Philippar, Katrin and Soll, Juergen and Engelmann, Julia C. and Engelsdorf, Timo and Voll, Lars M. and Hoth, Stefan (2012) Early Senescence and Cell Death in Arabidopsis saul1 Mutants Involves the PAD4-Dependent Salicylic Acid Pathway. PLANT PHYSIOLOGY, 159 (4). pp. 1477-1487. ISSN 0032-0889,
Full text not available from this repository. (Request a copy)Abstract
Age-dependent leaf senescence and cell death in Arabidopsis (Arabidopsis thaliana) requires activation of the transcription factor ORESARA1 (ORE1) and is not initiated prior to a leaf age of 28 d. Here, we investigate the conditional execution of events that regulate early senescence and cell death in senescence-associated ubiquitin ligase1 (saul1) mutants, deficient in the PLANT U-BOX-ARMADILLO E3 ubiquitin ligase SAUL1. In saul1 mutants challenged with low light, the switch of age-dependent cell death was turned on prematurely, as indicated by the accumulation of ORE1 transcripts, induction of the senescence marker gene SENESCENCE-ASSOCIATED GENE12, and cell death. However, ORE1 accumulation by itself was not sufficient to cause saul1 phenotypes, as demonstrated by double mutant analysis. Exposure of saul1 mutants to low light for only 24 h did not result in visible symptoms of senescence; however, the senescence-promoting transcription factor genes WRKY53, WRKY6, and NAC-LIKE ACTIVATED BY AP3/PI were up-regulated, indicating that senescence in saul1 seedlings was already initiated. To resolve the time course of gene expression, microarray experiments were performed at narrow intervals. Differential expression of the genes involved in salicylic acid and defense mechanisms were the earliest events detected, suggesting a central role for salicylic acid in saul1 senescence and cell death. The salicylic acid content increased in low-light-treated saul1 mutants, and application of exogenous salicylic acid was indeed sufficient to trigger saul1 senescence in permissive light conditions. Double mutant analyses showed that PHYTOALEXIN DEFICIENT4 (PAD4) but not NONEXPRESSER OF PR GENES1 (NPR1) is essential for saul1 phenotypes. Our results indicate that saul1 senescence depends on the PAD4-dependent salicylic acid pathway but does not require NPR1 signaling.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | E3 UBIQUITIN LIGASE; ENHANCED DISEASE SUSCEPTIBILITY; LEAF SENESCENCE; TRANSCRIPTION FACTOR; GENE-EXPRESSION; ABSCISIC-ACID; SIGNALING PATHWAY; STRESS RESPONSES; PLASMA-MEMBRANE; 26S PROTEASOME; |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Institut für Funktionelle Genomik > Lehrstuhl für Statistische Bioinformatik (Prof. Spang) |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 08 May 2020 05:10 |
| Last Modified: | 08 May 2020 05:10 |
| URI: | https://pred.uni-regensburg.de/id/eprint/18348 |
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