Guillaume Tena – PLANT STOMATA ENCYCLOPEDIA

Two plasma membrane-associated proteins that localize polarly at opposite sides of the meristemoid mother cell before its division. OPL2 is on the inside and BRXL2 on the outside domains of maturing stomatal guard cells

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两个与细胞膜相关的蛋白质，在分裂之前极性地定位在分生组织母细胞的相对侧面。OPL2位于不断成熟的气孔保卫细胞的内部，BRXL2位于外部区域。

Duas proteínas associadas à membrana plasmática que se localizam polarmente em lados opostos da célula-mãe meristemática antes da sua divisão. OPL2 está no interior e BRXL2 nos domínios externos das células-guarda estomáticas em maturação.

Dos proteínas asociadas a la membrana plasmática que se localizan polarmente en lados opuestos de la célula madre meristemática antes de su división. OPL2 está en el interior y BRXL2 en los dominios externos de las células guardas estomáticas en maduración.

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Interacting with both sides

Tena G. (2024)

Guillaume Tena,

Nat. Plants (2024) – https://doi.org/10.1038/s41477-024-01684-1 – https://www.nature.com/nplants/

Asymmetric division is a fundamental biological process that both ensures existing tissue maintenance and also creates new cell types. It is necessary to establish correct patterning, an important characteristic for stomata. In this lineage, many intracellular factors influence development, including receptors, MAP kinases, peptides, transcription factors, scaffolding proteins and so on. Several of them are polarized and mediate the asymmetric division or the fate of daughter cells in which they segregate.

The researchers concentrated on two plasma membrane-associated proteins that localize polarly at opposite sides of the meristemoid mother cell before its division. Situated on both sides of the future division plane, they each end in one of the two daughter cells: BREVIS RADIX-LIKE 2 (BRXL2) is inherited by the stomatal lineage ground cell, and OCTOPUS-LIKE 2 (OPL2) segregates in the meristemoid cell. Later on, as seen in striking in vivo fluorescent imaging, during the symmetric division of the guard mother cell that creates two guard cells, the patterns of these proteins become different but again opposite and mostly non-overlapping: OPL2 is on the inside and BRXL2 on the outside domains of maturing stomatal guard cells.

Phosphocode stomata control

Tena G. (2022)

Guillaume Tena,

Nat. Plants 8: 1209 – https://doi.org/10.1038/s41477-022-01286-9 –

https://www.nature.com/articles/s41477-022-01286-9#citeas

At the core of the wonderfully complex stomata lineage signalling circuit are a few master regulators that orchestrate development from young epidermal cells to the final pore-forming pair of guard cells. These transcription factors are needed for successive fate transitions. The first of them is SPEECHLESS (SPCH) and is necessary for early entry into this developmental pipeline through an asymmetric division. Various upstream pathways are already known to target SPCH and can modify its stability through phosphorylation.

Stomatal development has become a model for studying postembryonic lineage, asymmetric divisions and cell fate in plants

Stomatal development: Grasses vs Arabidopsis

Tena G. (2016)

Guillaume Tena ,

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Nature Plants 2, Article number: 16124 – DOI: 10.1038/nplants.2016.124 –

https://www.ncbi.nlm.nih.gov/pubmed/28221371 –

https://www.nature.com/articles/nplants2016124#citeas

Proc. Natl Acad. Sci. USA – http://doi.org/bmjn (2016)

Soon after plants colonized the land half a billion years ago, they developed stomata to facilitate gas exchange with their new environment. Much later, grasses branched out and successfully adapted to different environments. Grass stomata are unique: linearly aligned, with dumbbell-shaped guard cells, and more efficient. Raissig, Abrash and colleagues from Stanford University, USA, focused on the transcription factors involved in stomatal development in the model grass Brachypodium distachyon, and compared them with their better-known Arabidopsis orthologues.

Using an unbiased forward genetic screen to identify mutants lacking stomata, and reverse genetics with CRISPR-induced mutations, the authors identify and characterize a series of transcription factors involved in stomatal development in Brachypodium. Curiously, Arabidopsis and Brachypodium use orthologues in the same general developmental processes, but they are differently ‘wired’, with distinct functions and post-translational regulation.

Stomatal development has become a model for studying postembryonic lineage, asymmetric divisions and cell fate in plants. The accumulated knowledge of this gene regulatory network, central to the evolutionary success of grasses, could now be used for targeted approaches to increase crop productivity through more efficient stomata.

Grass stomata development and MUTE

Grass stomata development: MUTE communication

By Tena G. (2017)

In Nature Plants 3, 17051 (2017) – Science 355: 1215–1218 – https://doi.org/10.1038/nplants.2017.51 –

https://www.nature.com/articles/nplants201751#citeas

Stomata are little pores that interrupt the waxy and impermeable epidermal surface of the plant to allow gas exchange with the atmosphere. In eudicot plants, the pores are bordered by two bean-shaped guard cells and distributed evenly across leaf surfaces following strict spacing rules. In the diverse family of grasses that includes the domesticated cereals uniquely important for human history, stomata have a more complicated structure, with two dumbbell-shaped guard cells flanked on each side by two more helper cells called subsidiary cells (SCs). In an Article published in Science, Dominique Bergmann from Stanford and colleagues discover the molecular mechanism behind the development of SCs, which may explain the adaptability and success of grasses.

Credit: CULTURA CREATIVE (RF) / ALAMY STOCK PHOTO

The stomata developmental pathway in Arabidopsis has been extensively explored and used to study cell fate and asymmetrical division in plants. Several transcription factors in this pathway are conserved in the model grass Brachypodium distachyon (Bd). A genetic screen uncovered one mutant without SCs, suddenly cancelling millions of years of evolution. The affected gene is a basic helix–loop–helix transcription factor called MUTE, the orthologue of which in Arabidopsis controls guard mother cell identity and so the development of guard cells.

In Brachypodium, MUTE plays a slightly different role. BdMUTE is very precisely expressed in future stomata and, unlike its Arabidopsis counterpart, diffuses to the neighbouring cells to induce the asymmetrical division that will create SCs. Switching to physiological whole plant assays, the authors show that without the SCs, the mutant stomata cannot open wide or close tightly, gas exchange is limited, and their response to changing conditions is much slower. The ultimate consequence is a lower growth rate.

Stomata manage the delicate balance between plant carbon assimilation and water loss. Manipulating stomata to get better yields is slowly becoming a realistic option to make more efficient crops. By understanding the details of their development, we may not have to wait another 300 million years for the next evolutionary innovation.

Grass stomata development: MUTE communication

by Tena G. (2017)

Guillaume Tena

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In Nature Plants 3(4): 1751 – DOI: 10.1038/nplants.2017.51 –

https://www.researchgate.net/publication/315968168_Grass_stomata_development_MUTE_communication

Abstract:

Science 355 , 1215–1218 (2017) – Stomata are little pores that interrupt the waxy and impermeable epidermal surface of the plant to allow gas exchange with the atmosphere.

A lineage in stomatal development

Stomatal development: Securing a lineage

by Tena G. (2015)

citations — Guillaume Tena, Harvard Medical School

in Dev. Cell 33 , 136-149 –

http://www.nature.com/articles/nplants201571

The structural organization needed for efficient multicellularity derives from asymmetric cell divisions during development, which create functionally diverse and spatially oriented cells and tissues.