Biology subjects

Ibl, V.

Publications and source records attributed to Ibl, V..

4 recordsLinked to original sources

bioRxiv2026

The plant specific VPS2.2/HYADE of the ESCRT-III protein sorting machinery localizes to a secretory compartment and is required for cell division plane determination in Arabidopsis

Positioning of the division plane is a critical step during cellular development. While in animal cells the plane of cell division is defined during metaphase, in plants this decision is made before mitosis and includes the formation of a cytoskeletal structure termed the preprophase band (PPB). Although not essential, the PPB constitutes the earliest mark for the plane of cell division and coincides with the sites where the cell plate fuses with the parental plasma membrane during cytokinesis. Recent studies indicate that endo- and exocytosis are involved in remodelling of the cortical division zone. Here we show that PPBs, phragmoplasts, cell plates and cell walls are misplaced in Arabidopsis mutants of Atvps2.2/hyade (hya), a plant-specific component of the Endosomal Sorting Complex Required for Transport (ESCRT)-III. We demonstrate that the amino acid substitution Q71P of the hya-3 allele abolishes the homo- and heteromerization with other ESCRT-III components. Functional HYA-GFP fusion proteins are excluded from the canonical location of ESCRT-III complexes at multivesicular bodies (MVBs) and are absent from Brefeldin A (BFA) and Wortmannin (WM) sensitive compartments in Arabidopsis. HYA-GFP neither localize to early nor late endosomes but colocalizes with markers of secretory compartments such as the Qc-SNARE, SYP61 and with trans-Golgi-network (TGN) derived secretory Rab-A3 vesicles. Moreover, HYA-GFP locates to the extracellular space indicating that VPS2.2/HYA is involved in secretion. These results are consistent with a novel, non-canonical function of ESCRT-III in the establishment and maintenance of the cortical division zone via secretion.

plant biology↗

bioRxiv2025

The functional divergence of plant ESCRT components TOL3, SNF7.1, and VPS4 during salt stress response

Salinity, a major abiotic stressor, impacts protein trafficking and alters transport routes. The endosomal sorting complex required for transport (ESCRT)is a key player for membrane protein sorting and is increasingly recognized as pivotal element in abiotic stress responses. However, the functional role of ESCRT proteins in cereal crops under salt stress remains unexplored. Using the as near as possible to nature DRD-BIBLOX (Dark-Root device Brick Black Box), barley (Hordeum vulgare, L.), although relatively salt-tolerant, exhibits impaired germination, seedling growth, and an altered root system architecture (RSA) under high salinity. Shotgun proteomic analysis revealed spatio-temporal regulation of ESCRT proteins in shoots and roots during seedling development. We identified HvSNF7.1 and HvVPS4 as critical, but differently acting modulators of salt stress responses in barley tissues. In this study we further reveal novel functions of ESCRT-0-like TOM-1-like proteins (TOLs): Previously described as gatekeepers of degradative protein sorting and as regulators of abscisic acid signaling, growth, and heat stress responses in Arabidopsis (Arabidopsis thaliana), HvTOLs had not been characterized for their role in salinity adaptation during plant development. Functional analyses demonstrated lethality in Hvtoldouble and Hvtolquadruple mutants under standard growth conditions. In Arabidopsis, loss of AtTOL3 alone impaired germination and root growth under salt stress, underscoring the essential role of individual TOL proteins in the spatio-temporal regulation of abiotic stress adaptation. These findings highlight ESCRT-mediated trafficking as a key determinant of cereal resilience under saline conditions and provide a molecular framework for improving crop stress tolerance.

plant biology↗

bioRxiv2023

A bench-top dark-root device built with LEGO bricks enables a non-invasive plant root development analysis in soil conditions mirroring nature

Roots are the hidden parts of plants, anchoring their above ground counterparts in the soil. They are responsible for water and nutrient uptake, as well as for interacting with biotic and abiotic factors in the soil. The root system architecture (RSA) and its plasticity are crucial for resource acquisition and consequently correlate with plant performance, while being highly dependent on the surrounding environment, such as soil properties and therefore environmental conditions. Thus, especially for crop plants and regarding agricultural challenges, it is essential to perform molecular and phenotypic analyses of the root system under conditions as near as possible to nature (#asnearaspossibletonature). To prevent root illumination during experimental procedures, which would heavily affect root development, dark-root (D-Root) devices (DRDs) have been developed. In this article, we describe the construction and different applications of a sustainable, affordable, flexible, and easy to assemble open-hardware bench-top LEGO(R) DRD, the DRD-BIBLOX (Brick Black Box). The DRD-BIBLOX consists of one or more 3D-printed rhizoboxes which can be filled with soil, while still providing root visibility. The rhizoboxes sit in a scaffold of secondhand LEGO(R) bricks, which allows root development in the dark as well as non-invasive root-tracking with an infrared (IR) camera and an IR light emitting diode (LED) cluster. Proteomic analyses confirmed significant effects of root illumination on barley root and shoot proteome. Additionally, we confirmed the significant effect of root illumination on barley root and shoot phenotypes. Our data therefore reinforces the importance of the application of field conditions in the lab and the value of our novel device, the DRD-BIBLOX. We further provide a DRD-BIBLOX application spectrum, spanning from investigating a variety of plant species and soil conditions as well as simulating different environmental conditions and stresses, to proteomic and phenotypic analyses, including early root tracking in the dark.

plant biology↗

bioRxiv2019

Cytoskeleton members, MVBs and the ESCRT-III HvSNF7s are putative key players for protein sorting into protein bodies during barley endosperm development

Cereal endosperm is a short-lived tissue adapted for nutrient storage, containing specialized organelles, such as protein bodies (PBs) and protein storage vacuoles (PSVs), for the accumulation of storage proteins. PBs can be used as efficient biotechnological systems to produce high yields of stable recombinant proteins. During development, protein trafficking and storage require an extensive reorganization of the endomembrane system. Consequently, endomembrane-modifying proteins will influence the final grain quality, yield and recombinant protein production. Barley, a cereal crop of worldwide importance for the brewing industry, animal feed and to a lesser extent, human nutrition, has been identified as promising candidate for recombinant protein production. However, little is known about the molecular mechanism underlying endomembrane system remodeling during barley grain development. By using in vivo label-free quantitative proteomics profiling, we quantified 1,822 proteins across developing barley grains. Based on proteome annotation and a homology search, 95 proteins associated with the endomembrane system were identified, and 83 of these exhibited significant changes in abundance during grain development. Clustering analysis allowed characterization of three different development stages; notably, integration of proteomics data with in situ subcellular microscopic analyses showed a high abundance of cytoskeleton proteins associated with acidified protein bodies at the early development stages. Endosomal sorting complex required for transport (ESCRT)-related proteins and their transcripts are most abundant at early and mid-development. Specifically, multivesicular bodies (MVBs), and the ESCRT-III HvSNF7 proteins are associated with protein bodies (PBs) during barley endosperm development. Taken together, our proteomics results specifically identified members of the cytoskeleton, MVBs, and ESCRT as putative key players for protein sorting into PBs during barley endosperm development. These results present a comprehensive overview of proteins involved in the rearrangement of the endomembrane system during barley early grain development and will provide the basis for future work on engineering the endomembrane system to optimize nutrient content and to produce high yields of recombinant proteins.

plant biology↗