https://scholar.dgist.ac.kr/handle/20.500.11750/876 2026-04-05T01:12:00Z 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 https://scholar.dgist.ac.kr/handle/20.500.11750/58304 Title: MYB74 transcription factor guides de novo specification of epidermal cells in the abscission zone of Arabidopsis Author(s): Wen, Xiaohong; Lee, Chan Woong; Kim, Sunghwan; Hwang, Jae-Ung; Choi, Yoon Ha; Han, Soon-Ki; Lee, Eun Min; Yoon, Taek Han; Cha, Dong Gon; Lee, Seulbee; Son, Heejeong; Son, Jiwon; Jung, Su Hyun; Lee, Jiyoun; Lim, Heejin; Chen, Huize; Kim, Jong Kyoung; Kwak, June Myoung Abstract: The waxy cuticle layer is crucial for plant defence, growth and survival, and is produced by epidermal cells, which were thought to be specified only during embryogenesis. New surface cells are exposed during abscission, by which leaves, fruits, flowers and seeds are shed. Recent work has shown that nonepidermal residuum cells (RECs) can accumulate a protective cuticle layer after abscission, implying the potential de novo specification of epidermal cells by transdifferentiation. However, it remains unknown how this process occurs and what advantage this mechanism may offer over the other surface protection alternative, the wound healing pathways. Here we followed this transdifferentiation process with single-cell RNA sequencing analysis of RECs, showing that nonepidermal RECs transdifferentiate into epidermal cells through three distinct stages. During this vulnerable process, which involves a transient period when the protective layer is not yet formed, stress genes that protect the plant from environmental exposure are expressed before epidermis formation, ultimately facilitating cuticle development. We identify a central role for the transcription factor MYB74 in directing the transdifferentiation. In contrast to alternative protective mechanisms, our results suggest that de novo epidermal specification supports the subsequent growth of fruit at the abscission site. Altogether, we reveal a developmental programme by which plants use a transdifferentiation pathway to protect the plant while promoting growth. © The Author(s), under exclusive licence to Springer Nature Limited 2025. 2025-03-31T15:00:00Z