DGIST identifies mechanism behind epidermal cell transformation in residual plant cells, paving the way for controlling fruit growth

□ A research team led by Professor June M. Kwak from the Department of New Biology at DGIST (President Kunwoo Lee), in collaboration with Professor Jong Kyoung Kim’s team at POSTECH, has uncovered the mechanism and underlying reason behind the transformation of residual cells into epidermal cells during the abscission process, where plants naturally shed flowers, leaves, and fruits. This study not only provides valuable insights into plant survival strategies and growth mechanisms but is also expected to contribute to advancements in agricultural and food production technologies.

□ Plants have the remarkable ability to precisely shed unnecessary organs after seasonal changes or the completion of growth. During this process, residual cells (remaining cells) and separation cells (detaching cells) in the abscission zone play distinct roles. The research team discovered that residual cells do not merely remain after abscission; instead, they transform into epidermal cells through a three-step process, forming protective cuticle layers.

□ The study revealed that, in the early stage, photosynthesis-related genes are highly expressed in the residual cells. However, during the transitional phase, the expression of these genes decreases, while stress-resistance genes become more actively expressed to prepare for the period when the protective cuticle layer is temporarily absent. This response is interpreted as a self-protective strategy by plants against external threats.

□ In the final stage, genes related to cuticle biosynthesis and formation are expressed, resulting in the development of a protective layer on the newly exposed surface. In particular, the team identified the transcription factor MYB74[1] as a key regulator of the process by which residual cells transform into epidermal cells, with its disruption leading to the suppression of this transformation.

□ Generally, when plants are wounded, they protect their inner tissues by forming a rigid protective layer composed of lignin and suberin. The team investigated why, in the abscission zone, plants adopt a different strategy by transforming residual cells into epidermal cells. They found that when a lignin layer forms, the cells become rigid and can no longer expand or grow, whereas epidermal cells allow for the continued growth of internal tissues.

□ In particular, for fruit to grow properly, the receptacle (a foundational structure of the fruit), where residual cells are located, must also continue to grow. However, if residual cells fail to transform into epidermal cells, the growth of the receptacle is halted, ultimately preventing proper fruit development. The research team confirmed that, through this process, plants adopt the strategy of converting residual cells into epidermal cells to optimize fruit growth.

□ Professor June M. Kwak of DGIST stated, “This study is a significant achievement in uncovering the mechanism by which plants regulate cell fate to promote fruit growth. Developing technologies to control fruit growth based on these findings could enhance crop productivity and contribute to food security.”

□ This research was supported by the Samsung Science and Technology Foundation and the Ministry of Science and ICT. The research findings were published in the prestigious journal Nature Plants (IF 15.8).

- Corresponding Author E-mail Address : jkwak@dgist.ac.kr
 

[1] MYB74: a member of the MYB transcription factors, which belongs to a protein family derived from MYeloBlastosis (Myb). It plays a crucial role in regulating gene expression in both plants and animals.