VIB researchers uncover key genetic pathway in leaf development 

The cell cycle inhibitor SIAMESE-RELATED1 (SMR1) plays a crucial role in how leaves adapt to the environment

The surface of a leaf is composed of diverse cell types that are remarkably well-balanced and organized. The team of Prof. Lieven De Veylder (VIB-UGent Center for Plant Systems Biology) and colleagues from the University of Sheffield have made a significant breakthrough in understanding the development of leaf epidermis. The study, published in Nature Plants, could pave the way to more climate-resilient plants. 

Building a leaf 

The surface of a leaf (the leaf epidermis) plays a crucial role in maintaining water balance, facilitating gas exchange, defending against pathogens, and protecting underlying cells. To perform all those functions, the leaf epidermis is a tissue that consists of various cell types, such as trichomes, stomata (specialized cellular pores), and protective pavement cells. ​ 

Stomata and pavement cells can differentiate from the same stomatal lineage ground cells (SLGC). The ratio of stomata and pavement cells is an important factor in determining how well a plant can deal with drought. While previous research has provided many insights into how these different cell types are formed and work together, the genetic pathways responsible for pavement cell differentiation have remained largely unknown. A new study by Dr. Marieke Dubois and colleagues in the lab of Prof. Lieven De Veylder (VIB-UGent Center for Plant Systems Biology) now lifts the veil. 

The green color illustrates the expression of SMR1
The green color illustrates the expression of SMR1

From ground to pavement to climate resilience 

Using mutant Arabidopsis plants, the team discovered that the cell cycle inhibitor SIAMESE-RELATED1 (SMR1) is vital for the timely differentiation of SLGCs into pavement cells. In other words, SMR1 stops the stomatal lineage ground cells from renewing, and pushes them to differentiate into pavement cells. 

By modulating SMR1 expression and, thereby, the stomata-to-pavement cell ratio, researchers adjust leaf development so that leaves become better suited to changing environmental conditions. For example, by increasing the ratio of pavement cells to stomata, one can control water loss through evaporation, which is particularly relevant in the face of drought and other climate-related challenges. ​ 

Dr. Marieke Dubois: "We've found a previously unexplored genetic pathway that determines the pavement cell identity in the leaf epidermis. By identifying SMR1 as a critical regulator in the differentiation process, we can start to fine-tune stomata numbers in leaves, which will open up new possibilities for engineering climate-resilient plants." 
Prof. Lieven De Veylder agrees: "By targeting SMR1 researchers can develop the tools to enable strategies that enhance the resilience of crops and improve agricultural sustainability." 


SIAMESE-RELATED1 imposes differentiation of stomatal lineage ground cells into pavement cells. Dubois et al. Nature Plants, 2023. 

Steve Bers

Steve Bers

Science Communications Expert, VIB


About VIB

VIB’s core mission is to generate disruptive insights in the molecular underpinning of life and to translate these actively into impactful innovations for patients and society. VIB is an independent research institute where some 1,800 top scientists from Belgium and abroad conduct pioneering basic research. As such, they are pushing the boundaries of what we know about molecular mechanisms and how they rule living organisms such as human beings, animals, plants, and microorganisms. Based on a close partnership with five Flemish universities – Ghent University, KU Leuven, University of Antwerp, Vrije Universiteit Brussel, and Hasselt University – and supported by a solid funding program, VIB unites the expertise of all its collaborators and research groups in a single institute. VIB’s technology transfer activities translate research results into concrete benefits for society such as new diagnostics and therapies and agricultural innovations. These applications are often developed by young start-ups from VIB or through collaborations with other companies. This also leads to additional employment and bridges the gap between scientific research and entrepreneurship. VIB also engages actively in the public debate on biotechnology by developing and disseminating a wide range of science-based information. 

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