Biology subjects

Verstraeten, I.

Publications and source records attributed to Verstraeten, I..

5 recordsLinked to original sources

bioRxiv2026

Spatially-restricted metabolic delivery of auxin for selective adventitious root induction

Auxin impacts on nearly every aspect of plant growth and development. Its exogenous application therefore results in pleiotropic growth responses. Exploiting this activity for plant propagation requires avoiding or minimizing such off-target effects and is generally achieved as a trade-off between toxicity and organogenetic efficacity. We recently identified the compound HYSPARIN (HYS) with potent, and uniquely selective adventitious root inductive activity. Unlike other root-inducing compounds, HYS preferentially activates auxin responses in the shoot via an unknown mechanism. Here, we show that HYS acts as a shoot-specific proauxin. Rather than acting through auxin homeostasis, we found that HYS is hydrolysed in planta independently of ILR1/ILL amidohydrolases to release the synthetic auxin MCPA. Structure-activity relationship analysis confirmed a strong dependence on its MCPA moiety for activating auxin responses, and identified its promoiety as a determinant of shoot-specificity and activity. Selective application of MCPA also potently induces AR is consistent with a model in which HYS metabolism produces a spatially restricted, AR inductive auxin signal. The activation mechanism of HYS thus provides a conceptual framework for tissue-specific metabolic delivery of auxin and may enable the programmable delivery of other xenobiotics in plants.

plant biology↗

bioRxiv2024

Autoregulation of cluster root and nodule development by white lupin CCR1 receptor-like kinase

Root development is controlled by local and systemic regulatory mechanisms that optimize mineral nutrient uptake and carbon allocation. The Autoregulation of Nodulation (AoN) pathway defines a negative regulation of nodule development in Legumes as a way to regulate the costly production of nitrogen-fixing organs. This pathway is defined as a response to symbiotic interaction and has been shown to also control root formation to some extent. However, it remains unclear if root and nodule development are under coordinated genetic regulation. Here, we identified mutants with altered root development in white lupin, constitutively producing specialized lateral roots called cluster roots. We showed that the CCR1 receptor-kinase negatively regulates cluster root and nodule development and targets common molecular modules such as NIN/LBD16-NFYA, defining a novel pathway that we named Autoregulation of Development (AoDev). AoDev defines a negative systemic pathway controlling several types of root organ development, independently of symbiotic partners and nutrient availability.

plant biology↗

bioRxiv2022

Cell surface auxin signalling directly targets PIN-mediated auxin fluxes for adaptiveplant development

Phytohormone auxin and its directional transport mediate much of the remarkably plastic development of higher plants. Positive feedback between auxin signaling and transport is a key prerequisite for (i) self-organizing processes including vascular tissue formation and (ii) directional growth responses such as gravitropism. Here we identify a mechanism, by which auxin signaling directly targets PIN auxin transporters. Via the cell-surface ABP1-TMK1 receptor module, auxin rapidly induces phosphorylation and thus stabilization of PIN2. Following gravistimulation, initial auxin asymmetry activates autophosphorylation of the TMK1 kinase. This induces TMK1 interaction with and phosphorylation of PIN2, stabilizing PIN2 at the lower root side, thus reinforcing asymmetric auxin flow for root bending. Upstream of TMK1 in this regulation, ABP1 acts redundantly with the root-expressed ABP1-LIKE auxin receptor ABL3. Such positive feedback between cell-surface auxin signaling and PIN-mediated polar auxin transport is fundamental for robust root gravitropism and presumably also for other self-organizing developmental phenomena.

plant biology↗

bioRxiv2021

Rapid auxin-mediated phosphorylation of Myosin regulates trafficking and polarity in Arabidopsis

The signaling molecule auxin controls plant development through a well-known transcriptional mechanism that regulates many genes. However, auxin also triggers cellular responses within seconds or minutes, and mechanisms mediating such fast responses have remained elusive. Here, we identified an ultrafast auxin-mediated protein phosphorylation response in Arabidopsis roots that is largely independent of the canonical TIR1/AFB receptors. Among targets of this novel response are Myosin XI and its adaptor protein MadB2. We show that their auxin-mediated phosphorylation regulates trafficking and polar, subcellular distribution of PIN auxin transporters. This phosphorylation-based auxin signaling module is indispensable during developmental processes that rely on auxin-mediated PIN repolarization, such as termination of shoot gravitropic bending or vasculature formation and regeneration. Hence, we identified a fast, non-canonical auxin response targeting multiple cellular processes and revealed auxin-triggered phosphorylation of a myosin complex as the mechanism for feedback regulation of directional auxin transport, a central component of auxin canalization, which underlies self-organizing plant development.

plant biology↗

bioRxiv2018

Temperature-induced changes in wheat phosphoproteome reveal temperature-regulated interconversion of phosphoforms

Wheat (Triticum ssp.) is one of the most important human food sources. However, this crop is very sensitive to temperature changes. Specifically, processes during wheat leaf, flower and seed development and photosynthesis, which all contribute to the yield of this crop, are affected by high temperature. While this has to some extent been investigated on physiological, developmental and molecular levels, very little is known about early signalling events associated with an increase in temperature. Phosphorylation-mediated signalling mechanisms, which are quick and dynamic, are associated with plant growth and development, also under abiotic stress conditions. Therefore, we probed the impact of a short-term increase in temperature on the wheat leaf and spikelet phosphoproteome. The resulting data set provides the scientific community with a first large-scale plant phosphoproteome under the control of higher ambient temperature, which will be valuable for future studies. Our analyses also revealed a core set of common proteins between leaf and spikelet, suggesting some level of conserved regulatory mechanisms. Furthermore, we observed temperature-regulated interconversion of phosphoforms, which likely impacts protein activity.

plant biology↗