Biology subjects

Kuan, C.

Publications and source records attributed to Kuan, C..

3 recordsLinked to original sources

bioRxiv2026

The FERONIA receptor kinase is required for high humidity responses in Arabidopsis

High humidity greatly influences plant growth and development and triggers adaptive physiological responses such as leaf hyponasty (elongation of leaf petiole and upward leaf movement). A recent study identified Cyclic Nucleotide-Gated Ion Channels 2 and 4 (CNGC2/4)-mediated Ca2+ influx and Calmodulin Binding Transcription Activators 2 and 3 (CAMTA2/3)-mediated transcription as essential for high humidity response in Arabidopsis, but the upstream regulators that control these pathways remain unknown. Here, we show that the receptor-like kinase FERONIA and its co-receptor LORELEI-LIKE GPI-ANCHORED PROTEIN1 (LLG1) are required for a large portion of high humidity-associated Arabidopsis transcriptomic changes, including CNGC2, CAMTA-regulated genes, and cell wall remodeling genes, and for high humidity-induced leaf hyponasty. High humidity triggers a previously uncharacterized petiole-localized Ca2+ waves that precede hyponastic leaf movement. The petiole-localized Ca2+ signals were significantly altered in the fer-4 mutant. Thus, FERONIA is a key regulator of plant responses to extracellular high humidity. Highlights FERONIA plays a prominent role in transcriptomic responses to high humidity FERONIA is required for high humidity-induced leaf hyponasty High humidity induces petiole calcium waves FERONIA is required for normal petiole calcium waves in response to high humidity

plant biology↗

bioRxiv2024

Guard-cell phytosterol homeostasis is critical for proper stomatal development

Stomata regulate gas exchange and control water loss in response to the environmental stimuli and their distribution in the leaf epidermis is tightly regulated during development to ensure proper patterns. Although many studies have focused on the function of early stomatal lineage cells, little is known about the role of mature guard cells (GCs) in maintaining stomatal distribution. Here, we identified a previously uncharacterized enzyme, GDSL-type sterol esterase (GSEase), that is specifically expressed in mature guard cells and catalyzes lipid droplet-stored phytosterol ester degradation. Loss of GSEase decreased the level of free campesterol, a biosynthetic precursor of brassinosteroids (BRs), reduced BR level, and increased stomatal density in leaves, which could be further rescued by increasing the BR signaling. Furthermore, selectively reducing the BR response in GCs by utilizing the GSEase promoter-driven det2-1, a mutation causing BR biosynthesis deficiency, resulted in an elevated stomatal count, as demonstrated in gsease plants. These results indicate that GSEase plays a critical role in maintaining phytosterol homeostasis in GCs and the released phytosterols suppress the initiation of stomatal development in adjacent cells though the BR pathway.

plant biology↗

bioRxiv2023

The HOMEODOMAIN-Like protein HDL mediates chromatin organization and rewires leaf epidermal patterning

The Arabidopsis leaf epidermis is comprised of trichomes, pavement cells, and stomata, originating from versatile precursor cells capable of dividing or differentiating to create unique epidermal patterns. The mechanism governing these transitions and the maintenance of cell heterogeneity remains unclear. In this study, we identified a novel homeodomain-like superfamily protein, HDL, localized in chromocenters and playing a role in chromatin organization. HDL interacts with histone deacetylase 6 (HDA6) and methyltransferases, indicating its function in modulating chromatin accessibility. In hdl mutants, we observed moderately increased chromatin accessibility in the promoter region of protein-coding genes, along with reduced stomatal density and elevated trichome numbers on leaf surfaces. Corresponding to these phenotypes, stomatal-related gene expression decreased, while a transcriptional reporter for GLABRA2, a trichome initiation gene, exhibited higher and more variable expression levels. These findings highlight how HDL-mediated chromatin organization influences epidermal cell fate by modulating gene expression and enhancing cell heterogeneity within the leaf epidermis. One Sentence SummaryA homeodomain-like protein functions with histone modifiers to regulate chromatin and influence cell fate decisions.

plant biology↗