Cell type-specific attenuation of brassinosteroid signalling drives stomatal asymmetric cell division

作者：Eun‐Ji Kim, Cheng Zhang, Boyu Guo, Thomas Eekhout, Anaxi Houbaert, Jos R. Wendrich, Niels Vandamme, Manish Tiwari, Claire Simon--Vezo, Isabelle Vanhoutte, Yvan Saeys, Kun Wang, Yuxian Zhu, Bert De Rybel, Eugenia Russinova · 发表于：bioRxiv (Cold Spring Harbor Laboratory) · 年份：2022 · DOI：10.1101/2022.11.26.518021 · 被引用次数：3 · 研究领域：Plant Molecular Biology Research、Polysaccharides and Plant Cell Walls、Plant Reproductive Biology

Abstract In Arabidopsis thaliana , the negative brassinosteroid (BR) signalling regulator, BR INSENSITIVE2 (BIN2) promotes and restricts stomatal asymmetric cell division (ACD) depending on its subcellular localization, which is regulated by the stomatal lineage-specific scaffolding protein POLAR. BRs inactivate BIN2, but how they govern stomatal development remains unclear. Mapping the single-cell transcriptome of stomatal lineages with either exogenous BRs or the specific BIN2 inhibitor revealed that the two modes of BR activation triggered spatiotemporally distinct transcriptional responses. We established that when in a complex with POLAR and its closest homolog POLAR-LIKE1, BIN2 is insulated from BR-mediated inactivation, nevertheless, it remains sensitive to the inhibitor. Subsequently, BR signalling is attenuated in ACD precursors, whereas it remains active in epidermal cells that would undergo differentiation. Our study demonstrates how scaffold proteins contribute to cellular signal specificity of hormonal responses in plants.