https://scholar.dgist.ac.kr/handle/20.500.11750/876 2026-08-23T22:32:24Z https://scholar.dgist.ac.kr/handle/20.500.11750/60467 Title: Technovit Sectioning for High-Resolution Visualization of Tissue Anatomy and Gene Expression in the Floral Abscission Zone of Arabidopsis Author(s): Kim, Seonghwan; Yamaoka, Yasuyo; Kang, Joohyun; Lee, Yuree; Hwang, Jae-Ung; Kwak, June Myoung Abstract: Plant organ abscission is essential for stress adaptation, reproductive success, and crop productivity. Recent studies using bulk and single-cell transcriptomics have identified previously unrecognized cell types and regulatory networks that govern the abscission process. To validate these transcriptomic findings in vivo, we developed an optimized workflow for processing the floral abscission zone (AZ) of Arabidopsis. This workflow combines promoter-GUS staining with Technovit 7100 embedding and sectioning. This method enables high-resolution spatial visualization of both tissue and cellular anatomy, as well as the reporter activity within the AZ. Here, we present a clear, step-by-step protocol to facilitate the easy adoption of this method by other laboratories. 2026-01-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59939 Title: MYB Transcription Factors in Plant Developmental Plasticity Author(s): Hwang, Jae-Ung; Kim, Seonghwan; Son, Heejeong; Kwak, June Myoung Abstract: MYBs constitute one of the largest transcription factor families, with more than 200 genes identified in the Arabidopsis thaliana genome alone. MYBs are key regulators of developmental plasticity, cell differentiation, and plant adaptation to ever-changing environments owing to their large number, diverse expression patterns across different tissues and environmental conditions, and broad functional diversity. This review provides an updated overview of MYB functions in plants, with a focus on their roles in epidermal differentiation and the formation of extracellular protective barriers. MYB–employed regulatory strategies ensuring robust, precise, flexible, and spatially restricted gene expression are also highlighted. © 2025 Elsevier B.V., All rights reserved. 2025-11-30T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59140 Title: The chloroplast-targeted long noncoding RNA CHLORELLA mediates chloroplast functional transition across leaf ageing via anterograde signalling Author(s): Kang, Myeong Hoon; Lee, Juhyeon; Kim, Jinkwang; Mohammad, Hazara Begum; Park, Jeehye; Jung, Hyun Ju; Kim, Seonghwan; Lee, Heeho; Yang, Seong Wook; Kwak, June Myoung; Kim, Min-Sik; Lee, Jong-Chan; Lim, Pyung Ok Abstract: The transition from chloroplast biogenesis to degeneration during leaf senescence is critical for plants’ fitness, as it facilitates the relocation of nutrients to reproductive organs1, 2–3. However, it remains largely unknown how the timing of this transition is regulated by the coordination between chloroplasts and the nucleus4,5. Here we describe the regulatory mechanism underlying this transition in Arabidopsis thaliana. CHLOROPLAST-RELATED LONG NONCODING RNA (CHLORELLA) is highly co-expressed with genes supporting chloroplast function during leaf development. Leaves lacking CHLORELLA exhibit precocious senescence and reduced expression of chloroplast-associated genes, suggesting that CHLORELLA helps maintain chloroplast function. Mechanistically, CHLORELLA transcripts are translocated into chloroplasts and contribute to the accumulation of the plastid-encoded RNA polymerase complex. As leaves age, the expression of CHLORELLA decreases, leading to reduced plastid-encoded RNA polymerase accumulation and diminished transcription of photosynthesis-related genes, which may trigger leaf senescence. Moreover, CHLORELLA expression is activated by GOLDEN2-LIKE1 and GOLDEN2-LIKE2, master regulators of chloroplast development6, 7–8. Our study unravels a long-noncoding-RNA-based anterograde signalling mechanism that facilitates timely leaf senescence. © 2025 Elsevier B.V., All rights reserved. 2025-10-31T15:00:00Z https://scholar.dgist.ac.kr/handle/20.500.11750/59005 Title: Precision abscission for cell surface integrity and plant fitness Author(s): Lee, Y.; Yoon, T.; Lee, J.; Lee, M.; Oh, S.; Chen, H.; Jeon, S.; Cho, H.; Mang, H.; Kwak, June Myoung Abstract: Organ separation, or abscission, in plants is critical for discarding leaves, flowers, and to conserve resources, and as a form of defense. Little is known about the mechanism guiding the spatiotemporal precision of abscission, nor how protection of the newly formed surface is maintained. Here, we identify two neighboring cell types in Arabidopsis that coordinate their activities to ensure precise organ abscission. One cell type produces a honeycomb structure of lignin, which acts as a mechanical brace to localize cell wall breakdown and spatially restrict abscising cells. The second cell type forms a layer of new epidermis with a protective cutin coat, defects in which lead to an imperfect surface barrier susceptible to infection. This transdifferentiation event demonstrates de novo specification of epidermal cell identity, which was thought to be restricted to embryogenesis. 2017-12-03T15:00:00Z