Biology subjects

Stührwohldt, N.

Publications and source records attributed to Stührwohldt, N..

4 recordsLinked to original sources

bioRxiv2022

The sulfated peptide CLEL6 is a negative regulator of anthocyanin biosynthesis in Arabidopsis thaliana

Post-translationally modified peptides are now recognized as important regulators of plant stress responses. Here we identified the small sulfated CLE-LIKE6 (CLEL6) peptide as a negative regulator of stress-induced anthocyanin biosynthesis. The expression of CLEL6 and its negative effect on anthocyanin biosynthesis were strongly down-regulated by light. The function of CLEL6 depends on proteolytic processing of the CLEL6 precursor by the subtilisin-like serine proteinase 6.1 (SBT6.1), and on tyrosine sulfation by tyrosylprotein sulfotransferase (TPST). Loss of function mutants of either sbt6.1 or tpst showed significantly higher anthocyanin accumulation upon light stress. The overaccumulation phenotype of sbt6.1 and tpst was suppressed by application of mature CLEL6. Further confirming the role of CLEL6 as an inhibitor of anthocyanin biosynthesis, overexpression and external application of CLEL6 inhibited the expression of genes involved in anthocyanin biosynthesis in etiolated and light-stressed seedlings. Small post-translationally modified peptides are known to be perceived by leucine-rich-repeat receptor like kinases. Through a genetic approach, using a ROOT MERISTEM GROWTH FACTOR 1 INSENSITIVE (RGI) receptor quintuple mutant, we could show the essential function of the RGI receptor family in CLEL6 signaling. Our data indicate that CLEL6 inhibits anthocyanin biosynthesis through RGI receptors in dark-grown seedlings, and that this inhibition is released when CLEL6 expression is down-regulated upon transition to light. One sentence summaryThe formation of CLEL6 as a negative regulator of anthocyanin biosynthesis depends on proteolytic processing by SBT6.1, post-translational modification by TPST, and perception by RGI receptors.

plant biology↗

bioRxiv2021

TPST-dependent and -independent regulation of root development and signaling by PSK LRR receptor kinases in Arabidopsis

Tyrosine-sulfated peptides are key regulators of plant growth and development. The disulfated pentapeptide phytosulfokine (PSK) mediates growth via leucine-rich repeat receptor-like kinases, PSKR1 and PSKR2. PSKRs are part of a response module at the plasma membrane that mediates short-term growth responses, but downstream signaling of transcriptional regulation remains unexplored. In Arabidopsis, tyrosine sulfation is catalyzed by a single-copy gene (TPST). We performed a microarray-based transcriptome analysis in the tpst-1 mutant background that lacks sulfated peptides to identify PSK-regulated genes and genes that are regulated by other sulfated peptides. Of the 160 PSK-regulated genes, several had functions in root growth and development in agreement with shorter roots and a higher lateral root density in tpst-1. Further, tpst-1 roots developed higher numbers of root hairs and PSK induced expression of WEREWOLF (WER), its paralog MYB DOMAIN PROTEIN 23 (MYB23) and At1g66800 that maintain non-hair cell fate. The tpst-1 pskr1-3 pskr2-1 mutant showed even shorter roots, and higher lateral root and root hair density than tpst-1 revealing unexpected synergistic effects of ligand and PSK receptor deficiencies. While residual activities may exist, overexpression of PSKR1 in the tpst-1 background induced root growth suggesting that PSKR1 may be active in the absence of sulfated ligands. HighlightPhytosulfokine (PSK) receptor signaling promotes root elongation, determines lateral root density and maintains non-hair cell fate partially independent of TPST responsible for the activating sulfation of PSK.

plant biology↗

bioRxiv2020

Precursor processing by SBT3.8 and phytosulfokine signaling contribute to drought stress tolerance in Arabidopsis

Increasing drought stress poses a severe threat to agricultural productivity. Plants, however, evolved numerous mechanisms to cope with such environmental stress. Here we report that the stress-induced production of a peptide signal contributes to stress tolerance. The expression of phytosulfokine (PSK) peptide precursor genes, and transcripts of three subtilisin-like serine proteases, SBT1.4, SBT3.7 and SBT3.8 were found to be up-regulated in response to osmotic stress. Stress symptoms were enhanced in sbt3.8 loss-of-function mutants and could be alleviated by PSK treatment. Osmotic stress tolerance was improved in plants overexpression the precursor of PSK1 (proPSK1) or SBT3.8 resulting in higher fresh weight and improved lateral root development in the transgenic compared to wild-type plants. We further showed that SBT3.8 is involved in the biogenesis of the bioactive PSK peptide. ProPSK1 was cleaved by SBT3.8 at the C-terminus of the PSK pentapeptide. Processing by SBT3.8 depended on the aspartic acid residue adjacent to the cleavage site. ProPSK1 processing was impaired in the sbt3.8 mutant. The data suggest that increased expression in response to osmotic stress followed by the post-translational processing of proPSK1 by SBT3.8 leads to the production of PSK as a peptide signal for stress mitigation. HighlightThe expression of phytosulfokine precursor genes and processing by the subtilase SBT3.8 are upregulated in response to osmotic stress for improved drought tolerance in Arabidopsis.

plant biology↗

bioRxiv2018

Subtilase-mediated activation of CLEL peptides involves several processing events in consecutive compartments of the secretory pathway

Post-translationally modified peptides are involved in many aspects of plant growth and development. The maturation of these peptides from their larger precursors is still poorly understood. We show here that the biogenesis of CLEL6 and CLEL9 peptides in Arabidopsis thaliana requires a series of processing events in consecutive compartments of the secretory pathway. Following cleavage of the signal peptide upon entry into the endoplasmic reticulum (ER), the peptide precursors are processed in the cis-Golgi by the subtilase SBT6.1. SBT6.1-mediated cleavage within the variable domain allows for continued passage of the partially processed precursors through the secretory pathway, and is a prerequisite for subsequent post-translational modifications including tyrosine sulfation and proline hydroxylation within, and proteolytic maturation after exit from the Golgi. Activation by subtilase SBT3.8 in post-Golgi compartments depends on the N-terminal aspartate of the mature peptides. Our work highlights the complexity of post-translational precursor maturation allowing for stringent control of peptide biogenesis.

plant biology↗