Omanische Heilpflanze im Fokus der Phytochemie IPB-Wissenschaftler und Partner aus Dhofar haben jüngst die omanische Heilpflanze Terminalia dhofarica unter die phytochemische Lupe genommen. Die Pflanze ist reich an…
Geschmack ist vorhersagbar: Mit FlavorMiner. FlavorMiner heißt das Tool, das IPB-Chemiker und Partner aus Kolumbien jüngst entwickelt haben. Das Programm kann, basierend auf maschinellem Lernen (KI), anhand der…
Bassal, M.; Abukhalaf, M.; Majovsky, P.; Thieme, D.; Herr, T.; Ayash, M.; Tabassum, N.; Al Shweiki, M. R.; Proksch, C.; Hmedat, A.; Ziegler, J.; Lee, J.; Neumann, S.; Hoehenwarter, W.;Reshaping of the Arabidopsis thaliana Proteome Landscape and Co-regulation of Proteins in Development and ImmunityMol. Plant131709-1732(2020)DOI: 10.1016/j.molp.2020.09.024
Proteome remodeling is a fundamental adaptive response, and proteins in
complexes and functionally related proteins are often co-expressed.
Using a deep sampling strategy we define core proteomes of Arabidopsis thaliana
tissues with around 10 000 proteins per tissue, and absolutely quantify
(copy numbers per cell) nearly 16 000 proteins throughout the plant
lifecycle. A proteome-wide survey of global post-translational
modification revealed amino acid exchanges pointing to potential
conservation of translational infidelity in eukaryotes. Correlation
analysis of protein abundance uncovered potentially new tissue- and
age-specific roles of entire signaling modules regulating transcription
in photosynthesis, seed development, and senescence and abscission.
Among others, the data suggest a potential function of RD26 and other
NAC transcription factors in seed development related to desiccation
tolerance as well as a possible function of cysteine-rich receptor-like
kinases (CRKs) as ROS sensors in senescence. All of the components of
ribosome biogenesis factor (RBF) complexes were found to be co-expressed
in a tissue- and age-specific manner, indicating functional promiscuity
in the assembly of these less-studied protein complexes in Arabidopsis. Furthermore, we characterized detailed proteome remodeling in basal immunity by treating Arabidopsis
seeldings with flg22. Through simultaneously monitoring
phytohormone and transcript changes upon flg22 treatment, we obtained
strong evidence of suppression of jasmonate (JA) and JA-isoleucine
(JA-Ile) levels by deconjugation and hydroxylation by IAA-ALA RESISTANT3
(IAR3) and JASMONATE-INDUCED OXYGENASE 2 (JOX2), respectively, under
the control of JASMONATE INSENSITIVE 1 (MYC2), suggesting an
unrecognized role of a new JA regulatory switch in pattern-triggered
immunity. Taken together, the datasets generated in this study present
extensive coverage of the Arabidopsis proteome in various biological scenarios, providing a rich resource available to the whole plant science community.
Publikation
Jiang, X.; Hoehenwarter, W.; Scheel, D.; Lee, J.;Phosphorylation of the CAMTA3 Transcription Factor Triggers Its Destabilization and Nuclear ExportPlant Physiol.1841056-1071(2020)DOI: 10.1104/pp.20.00795
The Arabidopsis (Arabidopsis thaliana) calmodulin-binding
transcription activator3 (CAMTA3) is a repressor of immunity-related
genes but an activator of cold-induced or general stress-responsive
genes in plants. Post-transcriptional or posttranslational mechanisms
have been proposed to control CAMTA3 functions in different stress
responses. Here, we show that treatment with the bacterial flg22
elicitor induces CAMTA3 phosphorylation, which is accompanied by its
destabilization and nuclear export. Two flg22-responsive
mitogen-activated protein kinases (MAPKs), MPK3 and MPK6, directly
phosphorylate CAMTA3, with the phospho-sites contributing to CAMTA3
degradation and suppression of downstream target gene expression.
However, the flg22-induced nuclear export and phospho-mobility shift can
still be observed for the CAMTA3 phospho-null variant of the
MAPK-modified sites, suggesting additional flg22-responsive kinases
might be involved. Taken together, we propose that flg22-induced CAMTA3
depletion facilitates de-repression of downstream defense target genes,
which involves phosphorylation, increased protein turnover, and
nucleo-cytoplasmic trafficking.
Publikation
Tabassum, N.; Eschen-Lippold, L.; Athmer, B.; Baruah, M.; Brode, M.; Maldonado-Bonilla, L. D.; Hoehenwarter, W.; Hause, G.; Scheel, D.; Lee, J.;Phosphorylation‐dependent control of an RNA granule‐localized protein that fine‐tunes defence gene expression at a post‐transcriptional levelPlant J.1011023-1039(2020)DOI: 10.1111/tpj.14573
Mitogen‐activated protein kinase (MAPK) cascades are key signalling modules of plant defence responses to pathogen‐associated molecular patterns (PAMPs, e.g. bacterial flg22 peptide). The Tandem Zinc Finger Protein 9 (TZF9) is an RNA‐binding protein that is phosphorylated by two PAMP‐responsive MAPKs, MPK3 and MPK6. We mapped the major phosphosites in TZF9 and showed their importance for controlling in vitro RNA‐binding activity, in vivo flg22‐induced rapid disappearance of TZF9‐labelled processing body‐like structures and TZF9 protein turnover. Microarray analysis showed a strong discordance between transcriptome (total mRNA) and translatome (polysome‐associated mRNA) in the tzf9 mutant, with more mRNAs associated to ribosomes in the absence of TZF9. This suggests that TZF9 may sequester and inhibit translation of subsets of mRNAs. Fittingly, TZF9 physically interacts with poly(A)‐binding protein 2 (PAB2), a hallmark constituent of stress granules – a site for stress‐induced translational stalling/arrest. TZF9 even promotes stress granule assembly in the absence of stress. Hence, MAPKs may control defence gene expression post‐transcriptionally through release from translation arrest within TZF9‐PAB2‐containing RNA granules or perturbing PAB2 functions in translation control (e.g. in the mRNA closed‐loop model of translation).
Publikation
Trempel, F.; Eschen‐Lippold, L.; Bauer, N.; Ranf, S.; Westphal, L.; Scheel, D.; Lee, J.;A mutation in Asparagine‐Linked Glycosylation 12 (ALG12) leads to receptor misglycosylation and attenuated responses to multiple microbial elicitorsFEBS Lett.5942440-2451(2020)DOI: 10.1002/1873-3468.13850
Changes in cellular calcium levels are one of the earliest signalling events in plants exposed to pathogens or other exogenous factors. In a genetic screen, we identified an Arabidopsis thaliana ‘changed calcium elevation 1 ’ (cce1 ) mutant with attenuated calcium response to the bacterial flagellin flg22 peptide and several other elicitors. Whole genome re‐sequencing revealed a mutation in ALG12 (Asparagine‐Linked Glycosylation 12 ) that encodes the mannosyltransferase responsible for adding the eighth mannose residue in an α‐1,6 linkage to the dolichol‐PP‐oligosaccharide N ‐glycosylation glycan tree precursors. While properly targeted to the plasma membrane, misglycosylation of several receptors in the cce1 background suggests that N ‐glycosylation is required for proper functioning of client proteins.