The role of the plasma membrane-associated E3 ubiquitin ligase SAUL1 in suppression of premature senescence and reduced growth in plants
Zusammenfassung der Projektergebnisse
Different experimental approaches in physiology, genetics, and molecular biology have shown that the saul1 ubiquitin ligase mutant is an autoimmune mutant. The saul1 phenotype – reduced growth and cell death in all above-ground organs – is induced by a reduction in temperature or relative humidity, immune genes are upregulated, and the phenotype can be rescued in saul1 pad4 and saul1 eds1 double mutants. A suppressor screen with saul1 led to the identification of several suppressor mutations that are all located in the TIR-NB-LRR gene SOC3 (Suppressor Of Chilling Sensitive1-2 3). By analyzing resistance of saul1 soc3 double mutants and saul1 soc3 pub43 triple mutants we could show that SAUL1 and its closest paralogue PUB43 are positive regulators of PAMP-triggerd immunity (PTI). The plasma membrane-associated ubiquitin ligase SAUL1 is thus guarded by the immune receptor SOC3. However, SOC3 does not bind directly to SAUL1. We hypothesize that a heteromeric immune receptor complex consisting of SOC3 and CHS1 guards SAUL1. The function of SAUL1-type ubiquitin ligases at the plasma membrane appears to be conserved in land plants. The identification of SAUL1 target proteins, however, has turned out to be challenging. By combining TAP-tag purification and mass spectrometry and by testing plasma membrane-bound components of PTI we were recently able to identify two good candidate SAUL1 targets.
Projektbezogene Publikationen (Auswahl)
- Early senescence and cell death in Arabidopsis saul1 mutants involves the PAD4-dependent salicylic acid pathway. Plant Physiol 2012, 159:1477-1487
Vogelmann K, Drechsel G, Bergler J, Subert C, Philippar K, Soll J, Engelmann JC, Engelsdorf T, Voll LM, Hoth S
(Siehe online unter https://doi.org/10.1104/pp.112.196220) - Plasma membrane-association of SAUL1-type plant U-box armadillo repeat proteins is conserved in land plants. Front Plant Sci 2014, 5:37
Vogelmann K, Subert C, Danzberger N, Drechsel G, Bergler J, Kotur T, Burmester T, Hoth S
(Siehe online unter https://doi.org/10.3389/fpls.2014.00037) - Membrane-Associated Ubiquitin Ligase SAUL1 Suppresses Temperature- and Humidity-Dependent Autoimmunity in Arabidopsis. Mol Plant Microbe Interact 2016, 29:69-80
Disch EM, Tong M, Kotur T, Koch G, Wolf CA, Li X, Hoth S
(Siehe online unter https://doi.org/10.1094/MPMI-07-15-0146-R) - E3 ligase SAUL1 serves as a positive regulator of PAMP-triggered immunity and its homeostasis is monitored by immune receptor SOC3. New Phytol 2017, 215: 1516-1532
Tong M, Kotur T, Liang W, Vogelmann K, Kleine T, Leister D, Brieske C, Yang S, Lüdke D, Wiermer M, Zhang Y, Li X, Hoth S
(Siehe online unter https://doi.org/10.1111/nph.14678)
