Biology subjects

Sun, H.

Publications and source records attributed to Sun, H..

At least 127 records · Page 7Linked to original sources

bioRxiv2025

Multi-step genomics on single cells and live cultures in sub-nanoliter capsules

Single-cell sequencing methods uncover natural and induced variation between cells. Many functional genomic methods, however, require multiple steps that cannot yet be scaled to high throughput, including assays on living cells. Here we develop capsules with amphiphilic gel envelopes (CAGEs), which selectively retain cells and large analytes while being freely accessible to media, enzymes and reagents. Capsules enable high-throughput multi-step assays combining live-cell culture with genome-wide readouts. We establish methods for barcoding CAGE DNA libraries, and apply them to measure persistence of gene expression programs in cells by capturing the transcriptomes of tens of thousands of expanding clones in CAGEs. The compatibility of CAGEs with diverse enzymatic reactions will facilitate the expansion of the current repertoire of single-cell, high-throughput measurements and extension to live-cell assays.

genomics↗

bioRxiv2025

MAIS: an in-vitro sandbox enables adaptive neuromodulation via scalable neural interfaces

Brain-machine interfaces (BMIs) predominantly rely on static digital architectures to decode biological neuronal networks, a paradigm that is incompatible with natural neural coding in the human brain1-4. Bridging this gap is a critical step in combating neuronal dysfunction, enhancing brain functionality, and refining the precision of neuroprosthetics5. The integration of brain organoids with microelectrode array (MEA), as a class of BMIs, offers a humanized in vitro platform with unique biological compatibility advantages for dynamic neuronal decoding. This study resolves the biological-electronic encoding incompatibility of brain organoid-MEA Integration through three progressive breakthroughs. First, a human-machine hybrid agent is developed as a newly proposed bioengineered platform that couples brain organoids together with high-density MEAs and computational chips, enabling closed-loop perturbation of biological neuronal networks via exogenous signals. Second, through plasticity-driven real-time tracking of neuronal activity, we establish dynamically reconfigurable stimulation nodes that self-align with the electrophysiological states of the organoids. This resolves the exogenous-endogenous encoding mismatch by implementing plasticity-driven adaptation principles that ensure biological compatibility through spatially adaptive coordination. Finally, through shared plasticity rules rather than centralized control, we construct the first scalable multi-agent interactive system (MAIS) and demonstrate its real-world applications. Through designed scenarios of pathological/normal neuronal network interaction, we validate that MAIS achieves stable cross-network coordination. MAIS embodies a self-evolving neural coding sandbox in which plasticity-driven dynamic decoding bridges the compatibility gaps between biological and digital systems, providing a scalable and foundational infrastructure for human-centered neural interfaces.

bioengineering↗

bioRxiv2025

clusIBD: Robust Detection of Identity-by-descent (IBD) Segments Using Unphased Genetic Data from Poor-quality DNA Samples

Inferring relatedness through the detection of identity-by-descent (IBD) segments is widely used in many fields. However, existing methods are often powerless for poor-quality DNA samples. Here, we propose a method, clusIBD, which can robustly detect IBD segments using unphased genetic data with high genotype errors. We evaluated and compared the performance of clusIBD with IBIS, TRUFFLE, and IBDseq using simulated data, artificial poor-quality materials and ancient DNA samples. The results showed that clusIBD outperformed these state-of-the-art existing tools and may be a promising tool for kinship inference in fields such as ancient DNA analysis and criminal investigation (freely available at https://github.com/Ryan620/clusIBD/).

genetics↗

bioRxiv2025

Lipocalins are versatile regulators of development and stress response in mosses

Major physiological and developmental innovations, such as stress tolerance strategies and three-dimensional growth, are key to land plant adaptation and evolution, but their genetic basis remains to be fully understood. Although lipocalins are known for their role to optimize adaptation and development in animals, they are heavily understudied in plants. Here we show that lipocalins in the moss Physcomitrium patens are versatile regulators of miscellaneous key physiological and developmental processes. Phylogenetics analyses revealed three major groups of plant lipocalins, including a newly identified group that is restricted to seedless plants. The temperature-induced lipocalin gene in P. patens (PpTIL) is functionally conserved with flowering plants in response to various abiotic stresses (e.g., heat, cold, salt, and dehydration). We demonstrate that PpTIL not only regulates protonemal development and the transition from two-dimensional to three-dimensional growth, but also affects many other processes such as lipid transport and metabolism, auxin biosynthesis and transport, and chlorophyll catabolism. These findings provide major insights into the role of lipocalins in land plant evolution.

evolutionary biology↗

bioRxiv2025

Overlooked features lead to divergent neurobiological interpretations of brain-based machine learning biomarkers

A central objective in human neuroimaging is to understand the neurobiology underlying cognition and mental health. Machine learning models trained on brain connectivity data are increasingly used as tools for predicting behavioral phenotypes 1,2, enhancing precision medicine 3,4, and improving generalizability compared to traditional MRI studies 5. However, the high dimensionality of brain connectivity data makes model interpretation challenging 6. Prevailing practices within the field rely on sparsely selected brain connectivity features, implicitly interpreting identified feature networks as uniquely representative of a given phenotype while overlooking others. Here, we show that commonly overlooked brain connectivity features can achieve similar prediction accuracies while yielding markedly different neurobiological interpretations. Using four large-scale neuroimaging datasets spanning over 12,000 participants and 13 outcomes, we demonstrate that this phenomenon is widespread across cognitive, developmental, and psychiatric phenotypes. It extends to both functional connectivity (fMRI) and structural (DTI) connectomes and remains evident even in external validation. These findings suggest that common practices may lead to feature overinterpretation and a misrepresentation of the neurobiological bases of brain-behavior associations. Such interpretations present only the "tip of the iceberg" when certain disregarded features may be just as meaningful, potentially contributing to ongoing issues surrounding reproducibility within the field. More broadly, our results point to the possibility that multiple neurobiologically distinct models may exist for the same phenotype, with implications for identifying meaningful subtypes within clinical and research populations.

neuroscience↗

bioRxiv2025

Exogenous melatonin mitigates drought stress by promoting the living cortical area of roots in cotton

The root cortex plays a critical role in water absorption, influencing root function and metabolic activity. However, the effects of melatonin on root cortical cells and its role in drought resistance remain unclear. This study examines the impact of exogenous melatonin on the root cortex of cotton under drought stress, focusing on its relationship with water uptake and drought resilience. Cotton plants were treated with 8% PEG6000 for drought stress and 100 {micro}M melatonin by foliar application. The results demonstrated that melatonin application significantly increased the living cortical area of roots under drought stress, with notable increases of 26.34% and 59.00% at distances of 1 cm and 13 cm from the root tip, respectively. Melatonin also enhanced root cortical thickness, promoted osmotic regulation, increased respiratory enzyme activity, and improved water and nutrient uptake. Furthermore, melatonin application promoted both root and shoot growth. Notably, the living cortical area positively correlated with osmotic substance accumulation, root respiration, and absorption capacity under drought conditions. In conclusion, exogenous melatonin alleviates drought-induced damage by enhancing the living cortical area, optimizing osmotic regulation, and improving root absorption, thus promoting cotton growth and drought resistance. These findings highlight melatonin as a promising regulator for enhancing drought resistance. HighlightExogenous melatonin increases root cortical integrity of cotton roots under drought stress, improves the absorption of water and nutrients, promotes the growth of cotton, and enhances its drought resistance.

physiology↗

bioRxiv2025

Retinol Binding Protein 4 reactivates latent HIV-1 via the JAK/STAT5 and JNK pathways

Reactivation of the latent viral reservoirs is crucial for a cure of HIV/AIDS. However, current latency reversing agents are inefficient and the endogenous factors that have the potential to reactivate HIV in vivo remain poorly understood. To identify natural activators of latent HIV-1, we screened a comprehensive peptide/protein library derived from human hemofiltrate, representing the entire blood peptidome, using J-Lat cell lines harboring transcriptionally silent HIV-1 GFP reporter viruses. Fractions potently reactivating HIV-1 from latency contained human Retinol Binding Protein 4 (RBP4), the carrier of retinol (vitamin A). We found that retinol-bound holo-RBP4 but not retinol-free apo-RBP4 strongly reactivates HIV-1 in a variety of latently infected T cell lines. Functional analysis revealed that this reactivation depends on the JAK/STAT5 and JNK pathways but does not require retinoic acid production. High levels of RBP4 were detected in plasma from both healthy individuals and people living with HIV-1. Physiological concentrations of RBP4 induced significant viral reactivation in latently infected cells from individuals on long-term antiretroviral therapy with undetectable viral loads. As a potent natural HIV-1 latency-reversing agent, RBP4 offers a novel approach to activating the latent reservoirs and bringing us closer to a cure.

immunology↗

bioRxiv2025

Functional connectivity in the social perception pathway at birth is linked with attention to faces at 4 months

BackgroundProcessing faces and speech is supported by the right-lateralized social visual perception pathway (social pathway) involving medial temporal/visual 5 area (MT/V5) and superior temporal sulcus (STS). Little is known about development of the social pathway and its links with later social outcomes. We examined intrinsic functional connectivity (iFC) in the right social pathway in neurotypical neonates, compared it with iFC in the left social and bilateral dorsal attention pathways, and interrogated prospective links between iFC and social attention in neurodiverse neonates. MethodsiFC in the social and dorsal pathways was measured in 517 full-term neonates from the developing Human Connectome Project (dHCP) and 73 full-term Yale neonates [Mage=41.5 weeks (SD=1.9)]. Social attention was assessed in 36 Yale neonates at Mage=4.2 months (SD=0.4) months. ResultsIn the dHCP sample, the iFC indices were positive in all the pathways (all p-values < 0.001) and did not vary by sex [all p>0.275], but the iFC in the right-lateralized social pathway was higher than in the remaining pathways [all p<0.001] and was positively associated with age at scan [r(517)=0.251, p<0.011]. In the prospective neurodiverse Yale sample, the iFC in the right social pathway was positively associated with social attention at 4 months [p=0.007], and greater social attention at 4 months predicted better social functioning in the second year [p=0.010]. ConclusionsThe early development of intrinsic functional connectivity in the right social perception pathway represents an area of interest for identifying neural mechanisms underlying emergence of atypical social attention associated with autism.

neuroscience↗

bioRxiv2025

MuFIX - Enabling Combinations of Concurrent Optogenetics and Lock-in Amplification Fiber Photometry via Removal of Optogenetic Stimulation Crosstalk

Simultaneous fiber photometry and optogenetics is a powerful emerging technique for precisely studying the interactions of neuronal brain networks. However, spectral overlap between photometry and optogenetic components has severely limited the application of an all-optical approach. Due to spectral overlap, light from optogenetic stimulation saturates the photosensor and occludes photometry fluorescence, which is especially problematic in physically smaller model organism brains like mice. Here, we demonstrate the Multi-Frequency Interpolation X- talk removal algorithm (MuFIX, or {micro}FIX) for recovering crosstalk-contaminated photometry responses recorded with lock-in amplification. {micro}FIX exploits multi-frequency lock-in amplification by modeling the remaining uncontaminated data to interpolate across crosstalk- affected segments (R2 [~] 1.0); we found that this approach accurately recovers the original photometry response after demodulation (Pearsons r [~] 1.0). When applied to crosstalk- contaminated data, {micro}FIX recovered a photometry response closely resembling the dynamics of non-crosstalk photometry recorded simultaneously. Upon further verification using simulated and empirical data, we demonstrated that {micro}FIX reproduces any signal that underwent simulated crosstalk contamination (r [~] 1.0). We believe adopting {micro}FIX will enable experimental designs using simultaneous fiber photometry and optogenetics that were previously not feasible due to crosstalk.

neuroscience↗

bioRxiv2025

White-matter controllability at birth predicts social engagement and language outcomes in toddlerhood

Social engagement and language are connected through early development. Alterations in their development can have a prolonged impact on childrens lives. However, the role of white matter at birth in this ongoing connection is less well-known. Here, we investigate how white matter at birth jointly supports social engagement and language outcomes in 642 infants. We use edge-centric network control theory to quantify edge controllability, or the ability of white-matter connections to drive transitions between diverse brain states, at 1 month. Next, we used connectome-based predictive modeling (CPM) to predict the Quantitative Checklist for Autism in Toddlers (Q-CHAT) for social engagement risks and the Bayley Scales of Infant and Toddler Development (BSID-III) for language skills at 18 months from edge controllability. We created the social engagement network (SEN) to predict Q-CHAT scores and the language network (LAN) to predict BSID-III scores. The SEN and LAN were complex, spanning the whole brain. They also significantly overlapped in anatomy and generalized across measures. Controllability in the SEN at 1 month partially mediated associations between Q-CHAT and BSID-III language scores at 18 months. Further, controllability in the SEN significantly differed between term and preterm infants and predicted Q-CHAT scores in an external sample of preterm infants. Together, our results suggest that the intertwined nature of social engagement and language development is rooted in an infants white-matter controllability. Significance StatementDuring infancy and toddlerhood, social engagement and language emerge together. Delays are often observed in both simultaneously. These interactions persist into later childhood, potentially affecting life quality. We reveal that the interplay between social engagement and language milestones in toddlerhood is rooted in the infants structural connectivity, which may assist in early risk identification of developmental delays. Insights into the early brain foundations for emerging social engagement and language skills may open opportunities for individualized interventions to improve developmental outcomes.

neuroscience↗

bioRxiv2025

Defined cellular reprogramming of androgen receptor-active prostate cancer to neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) arises primarily through neuroendocrine transdifferentiation (NEtD) as an adaptive mechanism of therapeutic resistance. Models to define the functional effects of putative drivers of this process on androgen receptor (AR) signaling and NE cancer lineage programs are lacking. We adapted a genetically defined strategy from the field of cellular reprogramming to directly convert AR-active prostate cancer (ARPC) to AR-independent NEPC using candidate factors. We delineated critical roles of the pioneer factors ASCL1 and NeuroD1 in NEtD and uncovered their abilities to silence AR expression and signaling by remodeling chromatin at the somatically acquired AR enhancer and global AR binding sites with enhancer activity. We also elucidated the dynamic temporal changes in the transcriptomic and epigenomic landscapes of cells undergoing acute lineage conversion from ARPC to NEPC which should inform future therapeutic development. Further, we distinguished the activities of ASCL1 and NeuroD1 from the inactivation of RE-1 silencing transcription factor (REST), a master suppressor of a major neuronal gene program, in establishing a NEPC lineage state and in modulating the expression of genes associated with major histocompatibility complex class I (MHC I) antigen processing and presentation. These findings provide important, clinically relevant insights into the biological processes driving NEtD of prostate cancer.

cancer biology↗

bioRxiv2025

DNA G-quadruplex Profiling Reveals Functional and Mechanistic Role of G-quadruplexes in Skeletal Muscle Stem Cells

DNA G-quadruplexes (G4s) are non-canonical secondary structures formed in guanine-rich DNA sequences and play important roles in modulating biological processes through a variety of gene regulatory mechanisms. Emerging G4 profiling permits global mapping of endogenous G4 formation. Here in this study, we map the G4 landscapes in adult skeletal muscle stem cells (MuSCs) which are essential for injury induced muscle regeneration. Throughout the myogenic lineage progression of MuSCs from quiescent to activated and further differentiated cells, we uncover dynamic endogenous G4 formation with a pronounced G4 induction when MuSCs become activated and proliferating. We further demonstrate that the G4 induction promotes MuSC activation thus the regeneration process. Mechanistically, we found that promoter associated G4s regulate gene transcription through facilitating chromatin looping. Furthermore, we found that G4 sites are enriched for transcription factor (TF) binding events in activated MuSCs; MAX binds to G4 structures to synergistically facilitate chromatin looping and gene transcription thus promoting MuSC activation and regeneration. The above uncovered global regulatory functions/mechanisms are further dissected on the paradigm of Ccne1 promoter, demonstrating Ccne1 is a bona fide G4/MAX regulatory target in activated MuSCs. Altogether, our findings for the first time demonstrate the prevalent and dynamic formation of G4s in adult MuSCs and the mechanistic role of G4s in modulating gene expression and MuSC activation/proliferation.

molecular biology↗

bioRxiv2025

Positive allosteric modulation of emodepside sensitive Brugia malayi SLO-1F and Onchocerca volvulus SLO-1A potassium channels by GoSlo-SR-5-69

Human lymphatic filariasis and onchocerciasis are Neglected Tropical Diseases (NTDs), of major public health concern. Prophylaxis and treatment rely on anthelmintics that effectively eliminate migrating microfilariae but lack efficacy against adult filarial worms. To expedite the elimination of both diseases, the introduction of drugs with adulticidal activity is paramount. The broad-spectrum anthelmintic emodepside, a nematode selective SLO-1 K channel activator, has been considered a promising candidate for the treatment of onchocerciasis due to its macrofilaricidal activity against Onchocerca volvulus. Nevertheless, it is less effective against adult Brugia malayi, one of the causative agents of human lymphatic filariasis. Characterizing molecular and pharmacological disparities between highly conserved splice variant isoforms of B. malayi and O. volvulus SLO-1 K channels and identifying allosteric modulators that can increase emodepside potency on B. malayi SLO-1 K channels is necessary for therapeutic advance. In this study, we tested the effects of emodepside and the mammalian BK channel activator, GoSlo-SR-5-69 alone and in combination on Xenopus expressed B. malayi SLO-1F and O. volvulus SLO-1A channels. Additionally, binding poses of emodepside, and GoSlo-SR-5-69 were predicted on both channels using molecular docking. Ovo-SLO-1A was more sensitive to emodepside than Bma-SLO-1F. GoSlo-SR- 5-69 was a positive allosteric modulator, potentiating the effects of emodepside. Emodepside was docked at the S6 pocket below the selectivity filter for Bma-SLO-1F and Ovo-SLO-1A. The binding of emodepside in the S6 pocket indicated a stabilizing{pi} -{pi} interaction between F342 and the phenyl rings of emodepside which may contribute to the potency of emodepside on these filaria channels. Molecular docking suggested that GoSlo-SR-5-69 binds at the RCK1 pocket. This study reveals for the first time, allosteric modulation of filarial nematode SLO-1 K channels by a mammalian BK channel activator and highlights its ability to increase emodepside potency on the B. malayi SLO-1 K channel. Author SummaryB. malayi is one of the causative agents of lymphatic filariasis, while O. volvulus causes onchocerciasis. Elimination of adult B. malayi and O. volvulus is impeded by anthelmintics lacking adequate macrofilaricidal activity. The anthelmintic emodepside has microfilaricidal and macrofilaricidal activity. However, it exhibits poor efficacy against adult B. malayi in vivo. Here, we conducted a comparative pharmacological characterization of two closely related splice variants SLO-1 K channels of B. malayi and O. volvulus. Using voltage clamp, we tested the effects of emodepside and GoSlo-SR-5-69 independently and in combination on Xenopus expressed B. malayi SLO-1F and O. volvulus SLO-1A channels. Binding poses of emodepside, and GoSlo-SR-5-69 were predicted on both channels using molecular docking. We demonstrate that the O. volvulus SLO-1A receptor is more sensitive to emodepside than the B. malayi SLO-1F receptor. GoSlo-SR-5-69 is also a potentiator of emodepside responses. Homology modelling revealed that emodepside probably binds in the pore region of the B. malayi SLO-1F and O. volvulus SLO-1A channels, while GoSlo-SR-5-69 probably binds to the RCK1 domain of the channels. Our study provides new insights into similarities and differences shared between SLO-1 K channels of each species and reveals positive allosteric modulation by a mammalian SLO-1 K activator.

pathology↗

bioRxiv2025

Post-Ictal Gamma Oscillations Predict Hippocampal Structural Integrity in Mesial Temporal Lobe Epilepsy

The underlying histopathology and epileptic network of patients with mesial temporal lobe epilepsy (mTLE) are difficult to ascertain. Here, we report a novel electrical activity following seizure termination, termed post-ictal gamma oscillations (PIGOs), recorded in mice with intrahippocampal kainic acid injection and a patient with mTLE. PIGOs are characterized by a spectral shift of increased power in gamma frequencies relative to decreased power in other frequencies, generating a gamma peak. PIGOs are accompanied by increased intracellular calcium levels among parvalbumin-positive interneurons and a direct current shift. Only a subgroup of animals in the study had PIGOs. These animals had less pronounced hippocampal sclerosis (HS) than those without PIGOs. To illustrate the translational potential of these findings, we analyzed data from two patients with unilateral mTLE, one with PIGOs and the other without. The patient with PIGOs had symmetrical hippocampi on neuroimaging, whereas the other exhibited overly decreased interictal glucose uptake in left hippocampus, suggesting left-sided HS. After receiving laser ablation of mesial temporal regions, the patient with PIGOs became seizure-free, whereas the other did not. Our results suggest that PIGOs may serve as a biomarker for a milder form of HS in patients with mTLE and for predicting treatment outcomes.

neuroscience↗

bioRxiv2025

Gut microbiota phospholipids regulate intestinal gene expression and can counteract the effects of antibiotic treatment

The gut microbiome influences immune and metabolic homeostasis. Our research using non-obese diabetic (NOD) mice revealed that early-life antibiotic exposure remodels the gut microbiome affecting metabolism and accelerating type 1 diabetes (T1D) incidence, with cecal material transplant (CMT) mitigating the damage. Now examining murine intestinal lipidomic profiles, we identified 747 compounds. Comparing the lipidomic profiles of cecal contents of conventional and germ-free mice and their diets, we identified 87 microbially-produced lipids reduced by antibiotic exposure but CMT-restored. Parallel analysis of human fecal lipid profiles after azithromycin-exposure showed significant alterations with substantial overlap with mice. In vitro co-culture with mouse macrophages or small intestinal epithelial cells and human colonic epithelial cells identified phospholipids that repress inflammation through the NF{kappa}B pathway. Oral administration of these phospholipids to antibiotic-treated NOD mice reduced expression of ileal genes involved in early stages of T1D pathogenesis. These findings indicate potential therapeutic anti-inflammatory roles of microbially-produced lipids.

microbiology↗

bioRxiv2025

Integrating bulk and single cell RNA-seq refines transcriptomic profiles of individual C. elegans neurons

Neuron-specific morphology and function are fundamentally tied to differences in gene expression across the nervous system. We previously generated a single cell RNA-seq (scRNA-Seq) dataset for every anatomical neuron class in the C. elegans hermaphrodite. Here we present a complementary set of bulk RNA-seq samples for 52 of the 118 canonical neuron classes in C. elegans. We show that the bulk RNA-seq dataset captures both lowly expressed and noncoding RNAs that are not detected in the scRNA-Seq profile, but also includes false positives due to contamination by other cell types. We present an analytical strategy that integrates the two datasets, preserving both the specificity of scRNA-Seq data and the sensitivity of bulk RNA-Seq. We show that this integrated dataset enhances the sensitivity and accuracy of transcript detection and differential gene analysis. In addition, we show that the bulk RNA-Seq data set detects differentially expressed non-coding RNAs across neuron types, including multiple families of non-polyadenylated transcripts. We propose that our approach provides a new strategy for interrogating gene expression by bridging the gap between bulk and single cell methodologies for transcriptomic studies. We suggest that these datasets advance the goal of delineating the mechanisms that define morphology and connectivity in the nervous system.

genomics↗

bioRxiv2025

Cell type-specific eQTL detection from single-cell RNA-seq reveals post-transcriptional regulatory mechanisms in human islets

Gene regulatory networks (GRNs) must be robust to maintain cellular identity across individuals yet flexible to accommodate population genetic variants. Comparing expression quantitative trait loci (eQTLs) in health and disease can therefore reveal hidden players in gene regulation. Here, we developed a computational pipeline to infer post-transcriptional regulatory events and their functional consequences from eQTL signals located in the 3' untranslated region of genes using single-cell RNA sequencing. As a case study, we repurposed datasets from human islets of donors with and without type 2 diabetes (T2D). We identified eQTL landscapes differing by cell type and diabetes status, with cell-type specificity associated with gene differential expression and RNA-binding proteins. Integrating eQTLs with GWAS and miRNA hits linked variants in G6PC2, QDPR, and RELL1 to insulin secretion, endoplasmic reticulum stress, and oxidative phosphorylation. Our pipeline provides a framework to unravel post-transcriptional regulatory mechanisms in health and disease at cell type resolution.

genetics↗

bioRxiv2025

Guard cell photorespiration has a major impact on photosynthesis, growth and stomatal behavior in Arabidopsis

Photorespiration is a mandatory metabolic repair shunt of carbon fixation by the Calvin-Benson (CB) cycle in oxygenic phototrophs. Its extent depends mainly on the CO2/O2 ratio in chloroplasts, which is regulated via stomatal movements. However, despite comprehensive understanding on the role of photorespiration in mesophyll cells (MC), its role in guard cells (GC) is yet unknown. To analyze this issue, the key enzyme of photorespiration, glycine decarboxylase (GDC), was manipulated through overexpression and antisense suppression of the GDC H-protein gene. A positive correlation of GDC-H expression with growth, photosynthesis and carbohydrate biosynthesis was observed in the transgenic lines, demonstrating active photorespiration is involved in stomatal regulation. This view is supported by gas exchange measurements showing that optimized GC photorespiration improves plant acclimation towards conditions requiring a high photorespiratory capacity, including high light. Microscopic analysis revealed that altered photorespiratory flux also affected starch accumulation patterns in GC, eventually serving as the underlying mechanistic for altered stomatal behavior. Collectively, our data suggest that photorespiration is a key component of the regulatory circuit that coordinates stomatal movements with external and internal CO2 availability. Thus, manipulation of photorespiration in GC has the potential to engineer crops maintaining growth and photosynthesis under future climates. One-sentence summaryGuard-cell-specific manipulation of photorespiratory glycine decarboxylase reveals photorespiration is active in guard cells and makes a major contribution to stomatal metabolism and movements.

plant biology↗