Joel Erberich
Ph.D. Student in Biology, admitted Autumn 2019
All Publications
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SPEECHLESS duplication in grasses expands potential for environmental regulation of stomatal development.
bioRxiv : the preprint server for biology
2025
Abstract
Plants acquire atmospheric carbon dioxide for photosynthesis while minimizing water loss and do so by regulating stomatal function and development. The ancestral basic helix-loop-helix transcription factor (TF) gene that drove stomata production in early land plants diversified in sequence and function to become paralogs SPEECHLESS (SPCH), MUTE, and FAMA. Extant angiosperms use these three TFs and their heterodimer partners to regulate stomatal cell identities. Grasses exhibit a particularly interesting set of duplications and losses of SPCH. Using phylogenetic methods, we tracked the duplication of SPCH to the Poaceae-specific rho whole genome duplication and demonstrated that both paralogs remain under selection. By following responses to environmental change in B. distachyon plants bearing mutations in either BdSPCH1 or BdSPCH2, we reveal paralog-specific divergence in response to light or temperature shifts, and further show this behavior is conserved O. sativa SPCH paralogs. Plausible molecular mechanisms underpinning paralog divergence, and cellular mechanisms driving the stomatal phenotypes are supported by analyses of RNA and protein expression in B. distachyon and sequence variation among grasses. These studies suggest ways in which a duplication of a key stomatal regulator enables adaptation and could inform genetic strategies to mitigate anticipated stressors in agronomically important plants.
View details for DOI 10.1101/2025.07.29.667563
View details for PubMedID 40771893
View details for PubMedCentralID PMC12327695
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Multi-scale dynamics influence the division potential of stomatal lineage ground cells in Arabidopsis.
Nature communications
2025; 16 (1): 2612
Abstract
During development, many precursor lineages are flexible, producing variable numbers and types of progeny cells. What determines whether precursors differentiate or continue dividing? Here we take a quantitative approach that combines long-term live imaging, statistical modeling and computational simulations to probe the developmental flexibility of stomatal lineage ground cells (SLGC) in Arabidopsis leaves. We discover that cell size is a strong predictor of SLGC behaviour and that cell size is linked to division behaviour at multiple spatial scales. At the neighbourhood scale, cell size correlates with the strength of cell-cell signaling, which affects the rate at which SPEECHLESS (SPCH), a division-promoting transcription factor, is degraded. At the subcellular scale, cell size correlates with nuclear size, which modulates the concentration of SPCH in the nucleus. Our work shows how initial differences in SPCH levels are canalized by nuclear size and cell-cell signaling to inform the behaviour of a flexible cell type.
View details for DOI 10.1038/s41467-025-57730-9
View details for PubMedID 40097420
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Century-long timelines of herbarium genomes predict plant stomatal response to climate change.
Nature ecology & evolution
2024
Abstract
Dissecting plant responses to the environment is key to understanding whether and how plants adapt to anthropogenic climate change. Stomata, plants' pores for gas exchange, are expected to decrease in density following increased CO2 concentrations, a trend already observed in multiple plant species. However, it is unclear whether such responses are based on genetic changes and evolutionary adaptation. Here we make use of extensive knowledge of 43 genes in the stomatal development pathway and newly generated genome information of 191 Arabidopsis thaliana historical herbarium specimens collected over 193 years to directly link genetic variation with climate change. While we find that the essential transcription factors SPCH, MUTE and FAMA, central to stomatal development, are under strong evolutionary constraints, several regulators of stomatal development show signs of local adaptation in contemporary samples from different geographic regions. We then develop a functional score based on known effects of gene knock-out on stomatal development that recovers a classic pattern of stomatal density decrease over the past centuries, suggesting a genetic component contributing to this change. This approach combining historical genomics with functional experimental knowledge could allow further investigations of how different, even in historical samples unmeasurable, cellular plant phenotypes may have already responded to climate change through adaptive evolution.
View details for DOI 10.1038/s41559-024-02481-x
View details for PubMedID 39117952
View details for PubMedCentralID 8542704
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Targeting editing of tomatoSPEECHLESScis-regulatory regions generates plants with altered stomatal density in response to changing climate conditions.
bioRxiv : the preprint server for biology
2023
Abstract
Flexible developmental programs enable plants to customize their organ size and cellular composition. In leaves of eudicots, the stomatal lineage produces two essential cell types, stomata and pavement cells, but the total numbers and ratio of these cell types can vary. Central to this flexibility is the stomatal lineage initiating transcription factor, SPEECHLESS (SPCH). Here we show, by multiplex CRISPR/Cas9 editing of SlSPCH cis- regulatory sequences in tomato, that we can identify variants with altered stomatal development responses to light and temperature cues. Analysis of tomato leaf development across different conditions, aided by newly-created tools for live-cell imaging and translational reporters of SlSPCH and its paralogues SlMUTE and SlFAMA, revealed the series of cellular events that lead to the environmental change-driven responses in leaf form. Plants bearing the novel SlSPCH variants generated in this study are powerful resources for fundamental and applied studies of tomato resilience in response to climate change.Significance statement: Plants can change their shape, size and cellular composition in response to environmental cues. Here, by precise gene editing of a core stomatal development regulator gene in tomato, we generate new alleles with enhanced or dampened responses to light and temperature cues. Combined with live imaging of development, we show the genetic and cellular pathways that contribute to customization of the leaf epidermis, and how this could lead to better climate-adapted varieties.
View details for DOI 10.1101/2023.11.02.564550
View details for PubMedID 37961313