Rejuvenation of Plants? Discovery of a Molecular Switch that Controls Leaf Aging

1. What Was Discovered

In October 2025, a paper published in Nature Plants provided definitive evidence that the transition point from "youth" to "aging" in leaves is driven by long-chain non-coding RNA (lncRNA). The newly identified lncRNA CHLORELLA is produced in the nucleus→moves to the cytoplasm→reaches the chloroplast, where it binds to the PEP (plastid-encoded RNA polymerase) complex in the chloroplast and regulates the transcriptional activity of photosynthesis-related genes. As long as its expression level is high, the chloroplast remains in "operational mode," but when expression decreases, it switches to "aging mode."dx.doi.org

The commentary on Phys.org organizes the key points of the research for the general public, emphasizing that CHLORELLA is a molecular switch that controls the "timing of leaf aging."Phys.org

2. Background: From "Factory" to "Resource Source"

During the growth phase, leaves generate energy through photosynthesis, and as aging begins, the components of the chloroplast themselves transform into nutrients that are redistributed to seeds, stems, and roots. This is a key survival strategy for plants, but the signal for this switch has long been a mystery. This study is groundbreaking in that it demonstrated the role of lncRNA as an **"anterograde signal" from the nucleus to the chloroplast.**Phys.org

3. How Was It Discovered: An Interdisciplinary Approach

The research team used Arabidopsis as a model to extract lincRNA groups linked to chloroplast function through genetic screening, tracked RNA movement with single-molecule imaging, and identified interacting proteins through mass spectrometry. The results showed that CHLORELLA binds to the PEP complex and is directly involved in transcriptional regulation within the chloroplast.Phys.org

4. Who Presses the Switch? — GLK Transcription Factor

GLK (GOLDEN2-LIKE) is known as a transcription factor that governs the expression of photosynthetic apparatus, acting as the "chloroplast overseer." This study illustrated that GLK drives the expression of CHLORELLA upstream, maintaining high expression during the growth phase to sustain photosynthesis. As aging begins, GLK activity decreases, CHLORELLA diminishes, and the chloroplast shifts to "shutdown mode." The potential of GLK in crop improvement has been noted in previous reviews, and this pathway could become a highly feasible target for implementation.dx.doi.org

5. What Can Be Achieved: Scope of Application

• Improving Yield and Quality: If photosynthetic capacity can be maintained until just before maturity (so-called "stay-green" trait), it is expected to increase the accumulation of assimilates in grains and vegetables. The tissue- and time-specific control of CHLORELLA and GLK could be an option to maximize yield while avoiding excessive "greening."dx.doi.org

• Designing Environmental Resistance: Aging is closely linked with stress. By tuning the functional transition of chloroplasts mediated by lncRNA, it may be possible to achieve timely resource redistribution even under drought or nitrogen limitation.dx.doi.org

• Integration with Baseline Data: Groups of lncRNA involved in leaf aging have been overviewed in past research (hundreds in Arabidopsis), presenting an opportunity to re-evaluate the position of CHLORELLA as a network hub.Frontiers

6. Cautions and Limitations

• Model Plant Bias: The main material at present is Arabidopsis. Verification is needed to see if a similar pathway is conserved in crop species and whether there are side effects of expression regulation.dx.doi.org

• Yield Trade-off: Delayed aging is closely linked with delayed maturity. Overall design is essential, including ripening, disease resistance, and lodging. Reviews discuss the potential of GLK modification and the risks of excessive photosynthetic apparatus activity.nph.onlinelibrary.wiley.com

7. Digest of SNS Reactions (Post-publication from 10/10–11/1)

• Nature Plants Official announced the letter publication. The keyword **"lncRNA-based anterograde signal from nucleus to chloroplast"** spread within the community.X (formerly Twitter)

• English articles by Korean media (Chosun Biz, Dong-A Science, etc.) introduced the study, with voices pointing out the presence of "K-Plant Science."biz.chosun.com

• In the research community, attention was drawn to the mechanism of "lncRNA binding to the PEP complex," with cautious yet forward-looking comments like "crop application hinges on GLK and promoter timing control" appearing (shares on ResearchGate and academic SNS).ResearchGate

※ On major SNS, rather than a specific numerical buzz (large-scale trend), the discussion seemed to progress mainly among specialized accounts in the fields of plant physiology and genomics. The sources are based on official posts and shares on news and academic SNS.X (formerly Twitter)

8. Upcoming Research

1. Spatiotemporal Control: Temporal and tissue-specific control of CHLORELLA expression (promoter engineering, switchable CRISPRa).

2. Verification in Crop Species: Transcriptome and phenotypic analysis during aging in rice, maize, tomato, etc.

3. Breeding and Bio-design: Multi-gene design combining the GLK–CHLORELLA–PEP axis with existing stay-green genes and hormone pathways.dx.doi.org
   
   

Key Points of the Research (Bullet Points)

• Discovery: The lncRNA CHLORELLA produced in the nucleus moves to the chloroplast and acts on the PEP complex to control photosynthesis genes.dx.doi.org

• Control System: Upstream GLK maintains CHLORELLA expression, and its decline leads to chloroplast function entering aging mode.dx.doi.org

• Significance: Demonstrated the mechanism of RNA involvement in anterograde signaling. Expected applications in extending the photosynthesis period and optimizing yield in crops.dx.doi.org

• Primary and Secondary Information: Nature Plants (October 10, 2025), Phys.org (October 31).dx.doi.org
  
  

References (Sources)

• Phys.org "Molecular 'switch' that controls aging of plant leaves discovered" (October 31, 2025). Phys.org

• Nature Plants "The chloroplast-target