Biology subjects

Vissenberg, K.

Publications and source records attributed to Vissenberg, K..

3 recordsLinked to original sources

bioRxiv2023

A pectin-binding peptide with a structural and signaling role in the assembly of the plant cell wall

Pressurized cells with strong walls make up the hydrostatic skeleton of plants. Assembly and expansion of such stressed walls depend on a family of secreted RAPID ALKALINIZATION FACTOR (RALF) peptides which, curiously, bind both a membrane receptor complex and wall-localized LEUCINE-RICH REPEAT EXTENSINs (LRXs) in a mutually exclusive way. Here we show that, in root hairs, the RALF22 peptide has a dual structural and signaling role in cell expansion. Together with LRX1, it directs the compaction of charged pectin polymers at the root hair tip into periodic circumferential rings. Free RALF22 induces the formation of a complex with LORELEI-LIKE-GPI-ANCHORED PROTEIN 1 (LLG1) and FERONIA (FER), triggering adaptive cellular responses. These findings show how a peptide simultaneously functions as a structural component organizing cell wall architecture and as a signaling molecule that regulates this process. This mechanism may also underlie wall assembly and expansion in other plant cell types.

plant biology↗

bioRxiv2021

Auxin-triggered changes in the Arabidopsis root tip (phospho)proteome reveal novel root growth regulators

Auxin plays a dual role in growth regulation and, depending on the tissue and concentration of the hormone, it can either promote or inhibit division and expansion processes in plants. Recent studies revealed that, beyond transcriptional reprogramming, alternative auxin-controlled mechanisms regulate root growth. Here, we explored the impact of different auxin concentrations on the root tip proteome and phosphoproteome, generating a unique resource. From the phosphoproteome data we pinpointed (novel) growth regulators, such as the RALF34-THE1 module. Our results together with previously published studies suggest that auxin, H+-ATPases, cell wall modifications and cell wall sensing receptor-like kinases are tightly embedded in a pathway regulating cell elongation. Furthermore, our study assigned a novel role to MKK2 as a regulator of primary root growth and a (potential) regulator of auxin biosynthesis and signalling, and suggests the importance of the MKK2 Thr31 phosphorylation site for growth regulation in the Arabidopsis root tip. ONE SENTENCE SUMMARYAn auxin-triggered Arabidopsis root tip (phospho)proteome reveals novel root growth regulators

plant biology↗

bioRxiv2019

Brassinosteroids control gravitropism by changing cellulose orientation and mannan content in Arabidopsis hypocotyls

The force of gravity is a constant environmental factor. Plant shoots respond to gravity through negative gravitropism and gravity resistance. These responses are essential for plants to direct the growth of aerial organs away from the soil surface after germination and to keep an upright posture above ground. We took advantage of the effect of brassinosteroids on the two types of graviresponses in Arabidopsis thaliana hypocotyls to disentangle functions of cell wall polymers during etiolated shoot growth. The ability of etiolated Arabidopsis seedlings to grow upwards was suppressed in the presence of 24-epibrassinolide (EBL) but enhanced in the presence of brassinazole (BRZ), an inhibitor of brassinosteroid biosynthesis. These effects were accompanied by changes in cell wall mechanics and composition. Cell wall biochemical analyses and confocal microscopy of the cellulose-specific pontamine S4B dye revealed that the EBL and BRZ treatments correlated with changes in cellulose fibre organization and mannan content. Indeed, a longitudinal re-orientation of cellulose fibres supported upright growth whereas the presence of mannans reduced gravitropic bending. The negative effect of mannans on gravitropism is a new function for this class of hemicelluloses, highlighting evolutionary adaptations by which aquatic ancestors of terrestrial plants colonized land.

plant biology↗