Timing of transient darkness shapes carbon-nitrogen metabolism and sugar signaling in sugarcane
- 1University of Sao Paulo
Abstract
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 pathways in commercial sugarcane leaves. Early-day darkness significantly impaired photosynthetic induction and revealed a temporal disconnect between stomatal and metabolic limitations, whereas midday and late-day treatments caused temporary, time-specific disruptions in carbon assimilation. These shifts altered the balance between sucrose preservation and catabolic mobilization, leading to treatment-dependent changes in starch reserves and free amino acids. Core circadian components largely maintained their phase relationships, but their amplitudes varied across treatments, consistent with partial decoupling from carbon status. Darkness also reorganized energy signaling, with SnRK1 and DIN6 responses associated with greater declines in sucrose. Notably, trehalose-pathway transcripts showed marked changes in network connectivity, with ScTPSIIG consistently emerging as a highly connected candidate associated with photosynthetic performance, water-use traits, sugar sensing, and amino acid metabolism. Overall, these results indicate that the timing of carbon limitation and residual sucrose availability shape distinct metabolic responses, while trehalose metabolism provides a candidate regulatory layer coordinating carbon-nitrogen adjustment during the diel cycle, highlighting class II TPS proteins as targets for functional investigation of metabolic resilience in sugarcane.
Related
- Breeding innovations focused on drought tolerance, and Nitrogen and phosphorus uptake, for sustainable and climate-resilient sugarcane
- Physiological Determinants of High Nitrogen-Use Efficiency in Waxy Sorghum: Integrated Analysis of Biomass Production, Nitrogen Assimilation, and Antioxidant Metabolism
- When Metabolism Became Messaging: The Stepwise Evolution of the GABAergic Signaling System
- Repressed mTORC1 signaling and transient dendritic pruning support axonal regeneration in adult zebrafish
- Transient activation of ciliary CCR2 signaling promotes the initiation of adipogenesis.
BibTeX
@misc{leal2026timing,
title = {{Timing of transient darkness shapes carbon-nitrogen metabolism and sugar signaling in sugarcane}},
author = {G. M. Leal and H. O. de Oliveira and F. Farineli and A. Vanni-Lopes and W. V. M. Mira and A. F. Macedo and G. H. Romim and C. T. Hotta and E. I. S. Floh and B. V. Navarro and M. S. Buckeridge},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.01.748396},
url = {https://www.biorxiv.org/content/10.64898/2026.09.01.748396v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Timing of transient darkness shapes carbon-nitrogen metabolism and sugar signaling in sugarcane
AU - G. M. Leal
AU - H. O. de Oliveira
AU - F. Farineli
AU - A. Vanni-Lopes
AU - W. V. M. Mira
AU - A. F. Macedo
AU - G. H. Romim
AU - C. T. Hotta
AU - E. I. S. Floh
AU - B. V. Navarro
AU - M. S. Buckeridge
PY - 2026
DA - 2026/09/01
PB - bioRxiv
DO - 10.64898/2026.09.01.748396
UR - https://www.biorxiv.org/content/10.64898/2026.09.01.748396v1
AB - 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 pathways in commercial sugarcane leaves. Early-day darkness significantly impaired photosynthetic induction and revealed a temporal disconnect between stomatal and metabolic limitations, whereas midday and late-day treatments caused temporary, time-specific disruptions in carbon assimilation. These shifts altered the balance between sucrose preservation and catabolic mobilization, leading to treatment-dependent changes in starch reserves and free amino acids. Core circadian components largely maintained their phase relationships, but their amplitudes varied across treatments, consistent with partial decoupling from carbon status. Darkness also reorganized energy signaling, with SnRK1 and DIN6 responses associated with greater declines in sucrose. Notably, trehalose-pathway transcripts showed marked changes in network connectivity, with ScTPSIIG consistently emerging as a highly connected candidate associated with photosynthetic performance, water-use traits, sugar sensing, and amino acid metabolism. Overall, these results indicate that the timing of carbon limitation and residual sucrose availability shape distinct metabolic responses, while trehalose metabolism provides a candidate regulatory layer coordinating carbon-nitrogen adjustment during the diel cycle, highlighting class II TPS proteins as targets for functional investigation of metabolic resilience in sugarcane.
ER -