Biology subjects

Ruiz Duarte, P.

Publications and source records attributed to Ruiz Duarte, P..

4 recordsLinked to original sources

bioRxiv2026

A premitotic polarity program patterns the grass leaf epidermis

Transverse asymmetric cell divisions (ACDs) in grass leaf epidermal development produce large basal pavement cells and small apical specialised cells. These "patterning divisions" generate the long-short epidermal cell pattern that is distinctive of grasses. Here, we show that patterning divisions require premitotic basal polarisation of Bd-POLAR-LIKE1 (BdPL1) in the model grass Brachypodium distachyon. Loss of BdPL1 disrupted division-plane orientation and postmitotic cell-size asymmetry in all cell files, which resulted in epidermal patterning defects. Ectopic expression analyses demonstrated that BdPL1 polarisation was independent of cellular context and sufficient to promote supernumerary transverse divisions. Furthermore, the developmental regulators BdBREVIS RADIX-solo and BdYODA1 formed a post-division polarity domain enforcing cell fate asymmetry independently of BdPL1. We propose that the premitotic BdPL1 module enforces physical cell-division asymmetry contributing to medio-lateral patterning of cell types, whereas the postmitotic BdBRX-solo/ BdYDA1 module enforces within-file cell fate asymmetry. Together, they robustly pattern the grass leaf epidermis.

plant biology↗

bioRxiv2024

MUTE drives asymmetric divisions to form stomatal subsidiary cells in Crassulaceae succulents

Amongst the evolutionary innovations of many succulents is a photosynthetic lifestyle, where stomatal gas exchange is decoupled from light-dependent carbon fixation. Stomatal complexes in the emerging succulent model Kalanchoe laxiflora consist of two guard cells surrounded by three anisocytic subsidiary cells (SCs). Here, we show that these SCs shuttle ions and thus likely support stomatal movements. Furthermore, gene editing, reporter lines and protein overexpression implicate the stomatal transcription factor MUTE in facilitating additional rounds of asymmetric divisions that form SCs in succulents. This is opposite to the role of MUTE in Arabidopsis thaliana, where it stops rather than induces asymmetric divisions, but reminiscent of MUTEs SC-related function in grasses. Together, our work deciphers an intricate genetic mechanism that generates innovative stomatal morphology in Crassulaceae succulents.

plant biology↗

bioRxiv2019

Cytoskeleton dynamics control early events of lateral root initiation in Arabidopsis

How plant cells re-establish differential growth to initiate organs is poorly understood. Morphogenesis of lateral roots relies on the tightly controlled radial expansion and asymmetric division of founder cells. The cellular mechanisms that license and ensure these features are unknown. Here, we quantitatively analyse F-actin and microtubule dynamics during LR initiation. Using mutants, pharmacological and tissue-specific genetic perturbations, we show that dynamic reorganisation of both microtubule and F-actin networks is required for the asymmetric expansion of the founder cells. This cytoskeleton remodelling intertwine with auxin signalling in the pericycle and endodermis in order for founder cells to acquire a basic polarity required for initiating LR development. Our results reveal the conservation of cell remodelling and polarisation strategies between the Arabidopsis zygote and lateral root founder cells. We propose that coordinated, auxin-driven reorganisation of the cytoskeleton licenses asymmetric cell growth and divisions during embryonic and post-embryonic organogenesis. HIGHLIGHTSO_LIFailure for lateral root founder cells to undergo asymmetric radial expansion before division, leads to aberrant organ formation. C_LIO_LICortical microtubules arrays reorganise to facilitate this asymmetric expansion and F-actin the asymmetric division. C_LIO_LICytoskeletal reorganisation depends on auxin signalling. C_LIO_LINew genetic tools allow to perturb microtubules or actin in an inducible and cell-type specific manner. C_LI

plant biology↗

bioRxiv2018

ARF5/MONOPTEROS directly regulates miR390 expression in theArabidopsis thaliana primary root meristem

The root meristem is organized around a quiescent centre surrounded by stem cells that generate all cell types of the root. In the transit amplifying compartment progeny of stem cells further divide prior to differentiation. Auxin controls the size of this transit-amplifying compartment via Auxin Response Factors (ARF) that interact with Auxin Response Elements (AuxRE) in the promoter of their targets. The microRNA miR390 regulates abundance of ARF2, ARF3 and ARF4 by triggering the production of trans-acting (ta)-siRNA from TAS3. This miR390/TAS3/ARF regulatory module confers sensitivity and robustness to auxin responses in diverse developmental contexts. Here, we show that miR390 is expressed in the transit-amplifying compartment of the root meristem where it modulates response to auxin. A single AuxRE bound by ARF5/MONOPTEROS (MP) in miR390 promoter is necessary for miR390 expression in this compartment. We show that interfering with ARF5/MP dependent auxin signaling attenuates miR390 expression in the transit-amplifying compartment. Our results show that ARF5/MP regulates directly the expression of miR390 in the basal root meristem. We propose that ARF5, miR390 and the ta-siRNAs-regulated ARFs are necessary to maintain the size of the transit-amplifying region of the meristem.\n\nOne sentence summaryThe expression of miR390 in the Arabidopsis basal root meristem is controlled by ARF5/MONOPTEROS.

plant biology↗