{
  "id": 5383612,
  "title": "Timing of transient darkness shapes carbon-nitrogen metabolism and sugar signaling in sugarcane",
  "url": "https://urgent.news/2026/09/03/timing-of-transient-darkness-shapes-carbon-nitrogen-metabolism-and",
  "topic": "science",
  "section": "Science",
  "published": "2026-09-03T00:00:00.000Z",
  "source": {
    "name": "bioRxiv",
    "slug": "biorxiv",
    "url": "https://www.biorxiv.org/content/10.64898/2026.09.01.748396v1?rss=1"
  },
  "original_language": "en",
  "account": "Fluctuating light conditions are prevalent in agricultural settings. However, the precise ways in which C4 plants like sugarcane regulate their carbon and nitrogen metabolism in response to short-term carbon deprivation are not well understood. To investigate this, researchers subjected sugarcane leaves to transient darkness at various points throughout the diel cycle. They found that early-day darkness significantly impaired the plant's ability to initiate photosynthesis, revealing a temporal disconnect between the limitations imposed by stomatal closure and metabolic processes. Midday and late-day darkness caused temporary disruptions in carbon assimilation, altering the balance between sucrose conservation and catabolic release. This in turn affected starch reserves and concentrations of free amino acids, depending on the specific treatment. The core circadian clock components maintained their relative phase relationships, but their intensity varied with each treatment, suggesting a partial decoupling from the plant's carbon status. Additionally, the darkness treatment reorganized energy signaling pathways, leading to more pronounced declines in sucrose when SnRK1 and DIN6 were involved. Notably, transcripts related to the trehalose metabolic pathway exhibited significant changes in their network connectivity. Among these, ScTPSIIG, a protein involved in trehalose metabolism, emerged as a highly connected candidate associated with aspects of photosynthetic performance, water-use efficiency, sugar sensing, and amino acid dynamics. The findings collectively suggest that the timing of carbon limitation and the availability of residual sucrose play crucial roles in shaping distinct metabolic responses. Furthermore, trehalose metabolism emerges as a potential regulatory mechanism coordinating carbon and nitrogen adjustments across the diel cycle, with class II trehalose-phosphotransferase system (TPS) proteins standing out as promising targets for further research into enhancing metabolic resilience in sugarcane.",
  "summary": "Fluctuating light is common in field environments. Yet, the mechanisms by which C4 crops coordinate carbon and nitrogen metabolism during short-term carbon deprivation remain poorly understood. Here, we imposed transient darkness at different phases of the diel cycle to assess how the timing of light loss affects photosynthesis, carbohydrate turnover, amino acid dynamics, and sugar-sensing…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}