Stomatal development: a plant's perspective on cell polarity, cell fate transitions and intercellular communication
ABSTRACT The plant stomatal lineage manifests features common to many developmental contexts: precursor cells are chosen from an initially equivalent field of cells, undergo asymmetric and self-renewing divisions, communicate among themselves and respond to information from a distance. As we review here, the experimental accessibility of these epidermal lineages, particularly in Arabidopsis, has made stomata a conceptual and technical framework for the study of cell fate, stem cells, and cell polarity in plants.
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ABSTRACT: The root system is an imperative component of a plant, involved in water and nutrient acquisition from the soil. Any subtle change in the root system may lead to drastic changes in plant productivity. Both auxin and cytokinin are implicated in regulating various root developmental aspects. One of the major signaling cascades facilitating various hormonal and developmental allocations is the Mitogen Activated Protein Kinase (MAPK) cascade. Innumerable efforts have been made to unravel the complex nexus involved in rice root development. In spite of a plethora of studies, a comprehensive study aiming to decipher the plausible cross-talk of MAPK signaling module with auxin and cytokinin signaling components in rice is missing. In the present study, extensive phenomics analysis of different stages of rice roots; transcript profiling by qRT-PCR of entire gene family of MAPK, MAPKK and PIN genes; as well as protein level and activity of potential MAPKs was investigated using western and immuno kinase assays both on auxin and cytokinin treatment. The above study led to the identification of various novel rice root specific phenotypic traits by using GiA roots software framework. High expression profile of OsMPK3/6, OsMKK4/5 and OsPIN 1b/9 and their marked transcript level modulation in response to both auxin and cytokinin was observed. Finally, the protein levels and activity assay further substantiated our present findings. Thus, OsMPK3/6-OsMKK4/5 module is elucidated as the putative, key player in auxin-cytokinin interaction augmenting their role by differentially regulating the expression patterns of OsPIN 1b/9 in root development in rice.PLoS ONE 03/2015; 10(4). DOI:10.1371/journal.pone.0123620 · 3.53 Impact Factor
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ABSTRACT: Cell polarization is linked to fate determination during asymmetric division of plant stem cells, but the underlying molecular mechanisms remain unknown. In Arabidopsis, BREAKING OF ASYMMETRY IN THE STOMATAL LINEAGE (BASL) is polarized to control stomatal asymmetric division. A mitogen-activated protein kinase (MAPK) cascade determines terminal stomatal fate by promoting the degradation of the lineage determinant SPEECHLESS (SPCH). Here, we demonstrate that a positive-feedback loop between BASL and the MAPK pathway constitutes a polarity module at the cortex. Cortical localization of BASL requires phosphorylation mediated by MPK3/6. Phosphorylated BASL functions as a scaffold and recruits the MAPKKK YODA and MPK3/6 to spatially concentrate signaling at the cortex. Activated MPK3/6 reinforces the feedback loop by phosphorylating BASL and inhibits stomatal fate by phosphorylating SPCH. Polarization of the BASL-MAPK signaling feedback module represents a mechanism connecting cell polarity to fate differentiation during asymmetric stem cell division in plants. Copyright © 2015 Elsevier Inc. All rights reserved.Developmental Cell 04/2015; DOI:10.1016/j.devcel.2015.02.022 · 10.37 Impact Factor
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ABSTRACT: It has recently become evident that plant development, like animal development, has molecular patterning modules that are reused again and again to create different cell type patterns. Here we focus on three of these plant modules: (1) the MYB-bHLH-WD40 protein complex, (2) the transmembrane calpain protease DEFECTIVE KERNEL1 (DEK1), and (3) homeodomain leucine zipper (HD-ZIP) class IV transcription factors acting in concert with SIAMESE-related cyclin-dependent kinase inhibitors. These three modules initiate the patterning of multiple cell types in the plant epidermis: the regular spacing of trichomes (leaf hairs), the stripes of root hairs, diverse pigmentation patterns in petals, the scattering of giant cells, and the files of bulliform cells. Varied combinations of players and additional regulatory inputs partially account for the diversity of patterns that are generated by reusing the same molecular mechanisms. Copyright © 2015 Elsevier Ltd. All rights reserved.