Biology subjects

Heisler, M. G.

Publications and source records attributed to Heisler, M. G..

3 recordsLinked to original sources

bioRxiv2021

PINFORMED1 polarity in the shoot is insensitive to the polarity of neighbouring cells

In plants, epidermal cells are planar-polarized along an axis marked by the asymmetric localization patterns of several proteins including PIN-FORMED1 (PIN1), which facilitates the directional efflux of the plant hormone auxin to pattern phyllotaxis (Heisler et al., 2010; Mansfield et al., 2018; Reinhardt et al., 2003). While PIN1 polarity is known to be regulated non-cell autonomously via the MONOPTEROS (MP) transcription factor, how this occurs has not been determined (Bhatia et al., 2016). Here we use mosaic expression of the serine threonine kinase PINOID (PID) to test whether PIN1 polarizes according to the polarity of neighbouring cells. Our findings reveal that PIN1 is insensitive to the polarity of PIN1 in neighbouring cells arguing against auxin flux or extracellular auxin concentrations acting as a polarity cue, in contrast to previous model proposals (Abley et al., 2016; Stoma et al., 2008).

plant biology↗

bioRxiv2018

Auxin is not asymmetrically distributed in initiating Arabidopsis leaves

It has been proposed that asymmetric auxin levels within initiating leaves help establish leaf polarity, based in part on observations of the DII auxin sensor. Here we show that the mDII control sensor also exhibits an asymmetry and that according to the ratio-metric auxin sensor R2D2, no obvious asymmetry in auxin exists. Together with other recent findings, our results argue against the importance of auxin asymmetry in establishing leaf polarity.

developmental biology↗

bioRxiv2017

Cell type boundaries organize plant development

In plants the dorsoventral boundary of leaves defines an axis of symmetry through the centre of the organ separating the top (dorsal) and bottom (ventral) tissues. Although the positioning of this boundary is critical for leaf morphogenesis, how the boundary is established and how it influences development remains unclear. Using live-imaging and perturbation experiments we show that leaf orientation, morphology and position are pre-patterned by HD-ZIPIII and KAN gene expression in the shoot, leading to a model in which dorsoventral genes coordinate to regulate plant development by localizing auxin response between their expression domains. However we also find that auxin levels feedback on dorsoventral patterning by spatially organizing HD-ZIPIII and KAN expression in the shoot periphery. By demonstrating that the regulation of these genes by auxin also governs their response to wounds, our results also provide a parsimonious explanation for the influence of wounds on leaf dorsoventrality.\n\nOnce sentence summaryCell type boundaries regulate plant development

developmental biology↗