[Chin-Min Ho] The coordination of stomatal patterning and cuticle formation during leaf development

Stomata, microscopic pores on the leaf epidermis, are required for taking CO2 from the atmosphere for photosynthesis. Cuticular layers on the epidermis provide the first layer of protection. Stomata and the cuticle are two important characters for terrestrialization, a critical event in which organisms moved from the ocean to the land. To maintain the efficient photosynthesis rate, stomata are properly placed on leaf epidermis – meaning two stomata are never adjacent to each other. Clustered stomata with modified cuticular layers were reported 40 years in some barley mutants. However, the underlying mechanism was not clear. How is cuticle formation integrated with stomatal development during leaf morphogenesis? We addressed this question by misregulating MYB16, a positive regulator of cuticle development. We found the inhibition of MYB16 in the early stomatal lineage is required to maintain the proper structure and biomechanics in the cuticular layer, and thus to correctly place the polarity complex for proper stomatal patterning during leaf morphogenesis. This work illustrated the mechanisms by which biochemical signaling and mechanical properties are integrated to form a functional tissue and cell elasticity driving polarity and cell fate in stomatal patterning. Because the closed stomata and cuticle layers are important characters to control water loss, modulating the number of stomata and the development of cuticle layers on the leaf epidermis provides a strategy to improve the adaptability of plants and crops in extreme climates.




The first author of this paper is Mr. Shao-Li Yang from the Institute of Plant and Microbial Biology, Academia Sinica.