Biology subjects

Vermeer, J. E.

Publications and source records attributed to Vermeer, J. E..

3 recordsLinked to original sources

bioRxiv2026

MAP70-2 is required for division plane orientation during 3D differential growth within a tissue

Communication between tissues and cell division orientation are essential for organ development. During lateral root formation in Arabidopsis thaliana, three-dimensional differential growth is established within a tissue of interconnected and pressurized cells. To emerge, the new organ needs to overcome the mechanical constraints provided by the overlying tissues. How the division plane orientation within the growing organ encountering mechanical constrains is coordinated remains unclear. Here, we show that MICROTUBULE ASSOCIATED PROTEIN 70-2 contributes to this integration of mechanical feedback during lateral root development by being associated with division plane orientation during primordium formation. MAP70-2 expression in the lateral root primordium is dynamic, localizing to cell corners and the cortical division zone prior to cytokinesis. Loss of MAP70-2 leads to misoriented cell divisions in the early stage of lateral root development and defective morphogenesis. Here we propose that MAP70-2 integrates biochemical and mechanical cues to establish correct division plane orientation during three-dimensional differential growth to facilitate lateral root organogenesis.

plant biology↗

bioRxiv2025

A tightly regulated auxin signaling landscape is required for spatial accommodation of lateral roots in Arabidopsis

In Arabidopsis thaliana, lateral root (LR) development requires spatial accommodation responses in overlying endodermal cells. This includes loss of cell volume whilst maintaining membrane integrity to allow the expansion of the underlying LR primordia (LRPs). These accommodation responses are regulated by auxin-mediated signaling, specifically through Aux/IAA proteins, involving IAA3/SHY2. Plants that express a stabilized version of SHY2, shy2-2, in differentiated endodermal cells, CASP1pro::shy2-2 plants, fail to make LRs. Exogenous treatment with 1- naphthaleneacetic acid (NAA) was reported to partially restore LR formation in this spatial accommodation mutant. Using treatments with auxins with different transport properties, such as NAA, indole-3-acetic acid (IAA), and 2,4-dichlorophenoxyacetic acid (2,4-D), we assessed the ability of each auxin to rescue LR formation in CASP1pro::shy2-2 roots. This revealed that IAA is the most effective in partially restoring LR development, NAA is effective in inducing LRPs but cannot maintain their canonical phenotype, whereas 2,4-D induces non-controlled cell divisions. In addition, we show that in CASP1pro::shy2-2 roots, AUX1 appears to be repressed in the zone where oscillation of the auxin response have been described. Our study advances the understanding of auxin-regulated spatial accommodation mechanisms during LRP formation and highlights the complex interplay of auxin transport and signaling in bypassing the endodermal constraints.

plant biology↗

bioRxiv2024

ROS responsive Aux/IAA multimerization modulates auxin responses

Reactive oxygen species (ROS) function as key signals in plants to enable adaptation to environmental stresses. Plant roots respond to transient water stress by temporarily ceasing branching using the acclimative response xerobranching1. In this study, we report that a rapid ROS burst regulates Xerobranching by inducing multimerization of auxin repressor protein IAA3/SHY2. Mutations in specific cysteine residues in IAA3/SHY2 disrupt redox-mediated multimerization and interaction with co-repressor TPL, but not with auxin response partner ARF7 and auxin receptor TIR1. ROS-mediated oligomerization of IAA3/SHY2 is required for efficient ARF mediated target gene repression during Xerobranching and lateral root emergence. We demonstrate that AUX/IAA proteins vary in their redox mediated multimerization, revealing a new auxin response regulatory mechanism that directly connects ROS sensing to auxin signalling. Our study reveals how ROS, auxin and water stress intersect to shape acclimative responses in plant roots and maintain their phenotypic plasticity.

plant biology↗