METTL3-mediated ANXA2 inhibition confers neuroprotection in ischemic stroke: Evidence from in vivo and in vitro studies.

Given the important role of m6A, the most common and reversible mRNA modification, in the pathogenesis of ischemic stroke, this study investigates the mechanisms of m6A methyltransferase METTL3 in neuronal damage in ischemic stroke. In silico analysis was used to pinpoint the expression of ANXA2, which was verified in clinical peripheral blood samples. SD rats were used for middle cerebral artery occlusion (MCAO) establishment. The experimental data suggested that T lymphocytes were increased in peripheral blood samples of ischemic stroke patients and MCAO rats. The MCAO rats were treated with anti-ANXA2 alone or combined with RP101075 (T lymphocyte infiltration inhibitor), followed by brain injury assessment. Oxygen-glucose deprivation/reoxygenation (OGD/R) was induced in primary cortical neurons, where shRNAs targeting ANXA2 or METTL3, or overexpression plasmids of METTL3 were introduced to verify the regulatory function for METTL3. Inhibition of T lymphocyte migration to the ischemic brain reduced brain injury in MCAO rats and neuronal damage in OGD/R-exposed neurons. Ablation of ANXA2 in T lymphocytes inhibited the migration of T lymphocytes to the ischemic brain and reduced neuronal damage. Mechanistically, METTL3 reduced ANXA2 expression in T lymphocytes through m6A modification and inhibited p38MAPK/MMP-9 pathway activation, exerting protective effects against neuronal damage in ischemic stroke. Overall, this study reveals the neuroprotective effects of METTL3-mediated ANXA2/p38MAPK/MMP-9 inhibition against ischemic stroke.

Exosomal encapsulation of miR-3198 promotes proliferation and migration of trophoblasts in preeclampsia.

PURPOSE: Preeclampsia (PE) is a vascular remodeling disorder cloesly linked to trophoblast dysfunction, involving defects in their proliferation, migration, and apoptosis. Maternal exosomal microRNAs (miRNAs) have been reported to play pivotal roles in the development of PE. However, the mechanism underlying the role of maternal exosomes in trophoblast dysfunction regarding the development of PE is poorly understood. METHODS: Plasma exosomes from maternal peripheral blood were collected from pregnant women with PE and from those with normal pregnancy. Bioinformatics analysis was used to identify significantly differentially expressed miRNAs under these two conditions. The expression of the miR-3198 gene in plasma exosomes was detected using quantitative real-time polymerase chain reaction. Dual luciferase reporter assay was used to confirm binding of miR-3198 and 3'UTR region of WNT3. Cell proliferation was examined using the Cell Count Kit-8 and EdU assays, and flow cytometry was performed to detect apoptosis and cell cycle. Changes in cell migration were examined using transwell and scratch assays. RESULTS: Patients with PE showed decreased expression of plasma-derived exosomal miR-3198. The proliferation and migration abilities of HTR-8/SVneo and primary human trophoblast cells were both improved when cocultured with miR-3198-rich exosomes. Exposure to miR-3198-enriched exosomes facilitated cell cycle progression but reduced apoptosis in HTR-8/SVneo cells. Notably, overexpression of miR-3198 partially prevented the inhibitory effects of WNT3 on proliferation and migration in HTR-8/SVneo cells. CONCLUSION: Exosomal miR-3198 in the maternal peripheral blood may regulate the biological functions of trophoblasts by targeting WNT3 and influence the development of diseases of placental origin.

Afforestation enhances glomalin-related soil protein content but decreases its contribution to soil organic carbon in a subtropical karst area.

Afforestation on degraded croplands has been proposed as an effective measure to promote ecosystem functions including soil organic carbon (SOC) sequestration. Glomalin-related soil protein (GRSP) plays a crucial role in promoting the accumulation and stability of SOC. Nevertheless, mechanisms underlying the effects of afforestation on GRSP accumulation have not been well elucidated. In the present study, 14 pairs of maize fields and plantation forests were selected using a paired-site approach in a karst region of southwest China. By measuring soil GRSP and a variety of soil biotic and abiotic variables, the pattern of and controls on GRSP accumulation in response to afforestation were explored. The average content of total GRSP (T-GRSP) and its contribution to SOC in the maize field were 5.22 ± 0.29 mg g-1 and 42.33 ± 2.25%, and those in the plantation forest were 6.59 ± 0.32 mg g-1 and 25.77 ± 1.17%, respectively. T-GRSP content was increased by 26.4% on average, but its contribution to SOC was decreased by 39.1% following afforestation. T-GRSP content decreased as soil depth increased regardless of afforestation or not. Afforestation increased T-GRSP indirectly via its positive effects on arbuscular mycorrhizal fungi biomass, which was stimulated by afforestation through elevating fine root biomass or increasing the availability of labile C and N. The suppressed contribution of T-GRSP to SOC following afforestation was due to the relatively higher increase in other SOC components than T-GRSP and the significant increase of soil C:N ratio. Our study reveals the mechanisms underlying the effects of afforestation on T-GRSP accumulation, and is conducive to improving the mechanistic understanding of microbial control on SOC sequestration following afforestation.

Proteomic Discovery and Array-Based Validation of Biomarkers from Urinary Exosome by Supramolecular Probe.

Exosomes are nanoscale, membrane-enclosed vesicles with contents similar to their parent cells, which are rich in potential biomarkers. Urine, as a noninvasive sampling body fluid, has the advantages of being simple to collect, stable in protein, diverse and not regulated by homeostatic mechanisms of the body, making it a favorable target for studying tumor biomarkers. In this report, the urinary exosomal proteome was analyzed and high-throughput downstream validation was performed using a supramolecular probe-based capture and in situ detection. The technology demonstrated the efficient enrichment of exosomes with a high concentration (5.5 × 1010 particles/mL) and a high purity (2.607 × 1010 particles/mg) of exosomes from urine samples. Proteomic analysis of urine samples from patients with hepatocellular carcinoma and healthy individuals combined with proteomic screening techniques revealed that 68 proteins were up-regulated in patients with hepatocellular carcinoma. As a proof-of-principle study, three of these differentially expressed proteins, including OLFM4, HDGF and GDF15, were validated using the supramolecular probe-based array (48 samples per batch). These findings demonstrate the great potential of this approach toward a liquid biopsy for the discovery and validation of biomarkers from urinary exosomes, and it can be extended to various biological samples with lower content of exosomes.

Tree species diversity increases soil microbial carbon use efficiency in a subtropical forest.

Plant communities strongly influence soil microbial communities and, in turn, soil carbon (C) cycling. Microbial carbon use efficiency (CUE) is an important parameter for predicting soil C accumulation, yet how plant and soil microbial community traits influence microbial CUE remains poorly understood. Here, we determined how soil microbial CUE is influenced by plant and soil microbial community traits, by studying a natural gradient of plant species diversity in a subtropical forest. Our results showed that microbial CUE increased with increasing tree species diversity, suggesting a correlation between plant community traits and soil C storage. The specific soil properties that explained the greatest variation in microbial CUE were associated with microbial communities (biomass, enzyme activities and the ratio of oligotrophic to copiotrophic taxa); there were weaker correlations with plant-input properties, soil chemistry and soil organic C quality and its mineral protection. Overall, high microbial CUE was associated with soil properties correlated with increased tree species diversity: higher substrate availability (simple SOM chemical structures and weak mineral organic associations) and high microbial growth rates despite increased community dominance by oligotrophic strategists. Our results point to a mechanism by which increased tree species diversity may increase the forest C sink by affecting carbon use with the soil microbial community.

Polysaccharide of Atractylodes macrocephala Koidz(PAMK) protects against DEHP-induced apoptosis in grass carp hepatocytes.

Di(2-ethylhexyl) phthalate (DEHP) is a new environmental pollutant, which is widely used in plastic additives. DEHP and its metabolites pollute surface water and threaten the survival of fish. In order to investigate the mechanism of DEHP-induced apoptosis on grass carp hepatocytes, we treated grass carp hepatocytes with DEHP, and selected Atractylodes macrocephala Koidz (PAMK) to study its inhibitory effect on DEHP. The results showed that after DEHP exposure, apoptosis related proteins expression were increased significantly, leading to hepatocytes apoptosis. Moreover, AO/EB staining and Hoechst staining also showed that the number of apoptotic cells increased after DEHP exposure. It should be noted that PAMK simultaneous treatment could alleviate apoptosis induced by DEHP. The innovation of this study is that the application of Chinese herbal medicine (PAMK) to antagonize the damage of DEHP in fish was investigated for the first time. This study indicated that traditional Chinese medicine can also be used in fish production to reduce the accumulation of food-derived drugs.

The Clinical Application and Progress of Mirogabalin on Neuropathic Pain as a Novel Selective Gabapentinoids.

Background: Neuropathic pain is a complex sort of pain that is detrimental to individuals' health, both physically and mentally, but merely a small portion of them could witness pain alleviation. Mirogabalin, by distinctive binding characteristics of voltage-gated calcium channels, has won approval from the Japanese authority as a third member of gabapentinoids in Japan. Our review was aimed at encompassing the bulk of clinical research on mirogabalin, which included clinical trials, special considerations, coadministration studies, case reports, and cost-effectiveness studies. Methods: A review was carried out on a series of platforms, such as PubMed, MEDLINE, and Scopus, up to December 2021 using the keywords as follows: "mirogabalin OR mirogabalin besylate OR Tarlige OR DS-5565" AND "neuropathic pain OR Neuropathy." Results: Mirogabalin demonstrated analgesic activity and manageable adverse reactions and provides a new alternative for individuals with PHN or DPNP in 3 phase II and 4 III trials. Mirogabalin alleviated pain markedly in comparison with placebo. Administration of mirogabalin on a long-term basis is a flexible dosage regimen for patients with PHN. It is noteworthy that mirogabalin should be administrated cautiously when combined with probenecid and cimetidine on account of a slight increase in pharmacodynamics effects of mirogabalin. Conclusion: The development of mirogabalin allows further optimization of individual treatment strategies so as to provide more therapeutic choices in this medical domain.

Incidence and risk factors of postoperative delirium after pancreatic cancer surgery: a retrospective study.

PURPOSE: Postoperative delirium (POD) commonly occurs after major abdominal surgery and is associated with increased morbidity and mortality. There have been many studies on the relationship between POD and various surgeries, but research on POD after pancreatic cancer surgery is limited. The aim of this study was to identify the incidence and risk factors of POD after pancreatic cancer surgery. METHODS: The subjects of this retrospective analysis were 196 patients who were transferred for postoperative care after pancreatic cancer surgery, to a 12-bed critical care medicine ward at Shandong Provincial Hospital, affiliated with Shandong First Medical University, between January 2015 and December 2019. The patients were divided according to whether they suffered POD into a delirium group and a non-delirium group. Delirium was assessed using the Confusion Assessment Method for the Intensive Care Unit and two independent medical practitioners analyzed all the data. Univariate and multiple logistic regression analyses were performed. RESULTS: The overall delirium incidence was 20.41%, which increased to 29.03% for patients aged ≥ 70 years. POD was associated with age, smoking, the American Society of Anesthesiologists classification, the Acute Physiology and Chronic Health Evaluation II score, and the TNM stage of the cancer. The variables concerning sex, drinking, hypertension, a history of cerebral disease, surgery type, operation time, amount of bleeding, and the intraoperative use of dexmedetomidine did not differ significantly between the two groups. There was no significant difference in the length of ICU stay, with the exclusion of long-term stay for complications, between the groups, but POD tended to prolong the postoperative hospital stay and increase the risk of mortality. There was also a gradual decline in the incidence of POD between 2015 and 2019, especially from 2015 to 2018, after preventive measures were implemented. CONCLUSION: POD is related to many risk factors and worthy of attention. Appropriate management can reduce its incidence or at least shorten its duration.

Glycoproteomic Analysis of Urinary Extracellular Vesicles for Biomarkers of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) accounts for the most common form of primary liver cancer cases and constitutes a major health problem worldwide. The diagnosis of HCC is still challenging due to the low sensitivity and specificity of the serum α-fetoprotein (AFP) diagnostic method. Extracellular vesicles (EVs) are heterogeneous populations of phospholipid bilayer-enclosed vesicles that can be found in many biological fluids, and have great potential as circulating biomarkers for biomarker discovery and disease diagnosis. Protein glycosylation plays crucial roles in many biological processes and aberrant glycosylation is a hallmark of cancer. Herein, we performed a comprehensive glycoproteomic profiling of urinary EVs at the intact N-glycopeptide level to screen potential biomarkers for the diagnosis of HCC. With the control of the spectrum-level false discovery rate ≤1%, 756 intact N-glycopeptides with 154 N-glycosites, 158 peptide backbones, and 107 N-glycoproteins were identified. Out of 756 intact N-glycopeptides, 344 differentially expressed intact N-glycopeptides (DEGPs) were identified, corresponding to 308 upregulated and 36 downregulated N-glycopeptides, respectively. Compared to normal control (NC), the glycoproteins LG3BP, PIGR and KNG1 are upregulated in HCC-derived EVs, while ASPP2 is downregulated. The findings demonstrated that specific site-specific glycoforms in these glycoproteins from urinary EVs could be potential and efficient non-invasive candidate biomarkers for HCC diagnosis.

Exposing Cu(100) Surface via Ion-Implantation-Induced Oxidization and Etching for Promoting Hydrogen Evolution Reaction.

Metallic materials with unique surface structure have attracted much attention due to their unique physical and chemical properties. However, it is hard to prepare bulk metallic materials with special crystal faces, especially at the nanoscale. Herein, we report an efficient method to adjust the surface structure of a Cu plate which combines ion implantation technology with the oxidation-etching process. The large number of vacancies generated by ion implantation induced the electrochemical oxidation of several atomic layers in depth; after chemical etching, the Cu(100) planes were exposed on the surface of the Cu plate. As a catalyst for acid hydrogen evolution reaction, the Cu plate with (100) planes merely needs 273 mV to deliver a current density of 10 mA/cm2 because the high-energy (100) surface has moderate hydrogen adsorption and desorption capability. This work provides an appealing strategy to engineer the surface structure of bulk metallic materials and improve their catalytic properties.

Mature conifers assimilate nitrate as efficiently as ammonium from soils in four forest plantations.

Conifers are considered to prefer to take up ammonium (NH4+ ) over nitrate (NO3- ). However, this conclusion is mainly based on hydroponic experiments that separate roots from soils. It remains unclear to what extent mature conifers can use nitrate compared to ammonium under field conditions where both roots and soil microbes compete for nitrogen (N). We conducted an in situ whole mature tree nitrogen-15 (15 N) labeling experiment (15 NH4+ vs 15 NO3- ) over 15 d to quantify ammonium and nitrate uptake and assimilation rates in four 40-yr-old monoculture coniferous plantations (Pinus koraiensis, Pinus sylvestris, Picea koraiensis and Larix olgensis, respectively). For the whole tree, 15 NO3- contributed 39% to 90% to total 15 N tracer uptake among four plantations during the study period. At day 3, the 15 NO3- accounted for 77%, 64%, 62% and 59% by Larix olgensis, Pinus koraiensis, Pinus sylvestris and Picea koraiensis, respectively. Our study indicates that mature coniferous trees assimilated nitrate as efficiently as ammonium from soils even at low soil nitrate concentration, in contrast to the results from hydroponic experiments showing that ammonium uptake dominated over nitrate. This implies that mature conifers can adapt to increasing availability of nitrate in soil, for example, under the context of globalization of N deposition and global warming.

Long-term measurements in a mixed-grass prairie reveal a change in soil organic carbon recalcitrance and its environmental sensitivity under warming.

Soil respiration, the major pathway for ecosystem carbon (C) loss, has the potential to enter a positive feedback loop with the atmospheric CO2 due to climate warming. For reliable projections of climate-carbon feedbacks, accurate quantification of soil respiration and identification of mechanisms that control its variability are essential. Process-based models simulate soil respiration as functions of belowground C input, organic matter quality, and sensitivity to environmental conditions. However, evaluation and calibration of process-based models against the long-term in situ measurements are rare. Here, we evaluate the performance of the Terrestrial ECOsystem (TECO) model in simulating total and heterotrophic soil respiration measured during a 16-year warming experiment in a mixed-grass prairie; calibrate model parameters against these and other measurements collected during the experiment; and explore whether the mechanisms of C dynamics have changed over the years. Calibrating model parameters against observations of individual years substantially improved model performance in comparison to pre-calibration simulations, explaining 79-86% of variability in observed soil respiration. Interannual variation of the calibrated model parameters indicated increasing recalcitrance of soil C and changing environmental sensitivity of microbes. Overall, we found that (1) soil organic C became more recalcitrant in intact soil compared to root-free soil; (2) warming offset the effects of increasing C recalcitrance in intact soil and changed microbial sensitivity to moisture conditions. These findings indicate that soil respiration may decrease in the future due to C quality, but this decrease may be offset by warming-induced changes in C cycling mechanisms and their responses to moisture conditions.

An Improved Localization Method for the Transition between Autonomous Underwater Vehicle Homing and Docking.

Docking technology for autonomous underwater vehicles (AUVs) involves energy supply, data exchange and navigation, and plays an important role to extend the endurance of the AUVs. The navigation method used in the transition between AUV homing and docking influences subsequent tasks. How to improve the accuracy of the navigation in this stage is important. However, when using ultra-short baseline (USBL), outliers and slow localization updating rates could possibly cause localization errors. Optical navigation methods using underwater lights and cameras are easily affected by the ambient light. All these may reduce the rate of successful docking. In this paper, research on an improved localization method based on multi-sensor information fusion is carried out. To improve the localization performance of AUVs under motion mutation and light variation conditions, an improved underwater simultaneous localization and mapping algorithm based on ORB features (IU-ORBSALM) is proposed. A nonlinear optimization method is proposed to optimize the scale of monocular visual odometry in IU-ORBSLAM and the AUV pose. Localization tests and five docking missions are executed in a swimming pool. The localization results indicate that the localization accuracy and update rate are both improved. The 100% successful docking rate achieved verifies the feasibility of the proposed localization method.

Substrate stoichiometry determines nitrogen fixation throughout succession in southern Chinese forests.

The traditional view holds that biological nitrogen (N) fixation often peaks in early- or mid-successional ecosystems and declines throughout succession based on the hypothesis that soil N richness and/or phosphorus (P) depletion become disadvantageous to N fixers. This view, however, fails to support the observation that N fixers can remain active in many old-growth forests despite the presence of N-rich and/or P-limiting soils. Here, we found unexpected increases in N fixation rates in the soil, forest floor, and moss throughout three successional forests and along six age-gradient forests in southern China. We further found that the variation in N fixation was controlled by substrate carbon(C) : N and C : (N : P) stoichiometry rather than by substrate N or P. Our findings highlight the utility of ecological stoichiometry in illuminating the mechanisms that couple forest succession and N cycling.

Selective area oxidation of copper derived from chemical vapor deposited graphene microstructure.

The barrier properties of graphene coating are highly correlated with its microstructure which is then determined by the chemical vapor deposition (CVD) growth history on metals. We demonstrate here an unrevealed selective area oxidation of copper under graphene, which is derived from the implicit-etching-controlled CVD growth mode of graphene. By charactering and analyzing the selective area patterns of Cu oxidation, an etched pattern trace with nano/microvoids during graphene growth has been proposed to account for this. Based on such selective oxidation of Cu, distributed galvanic corrosion will be triggered and proceed locally at the interface of graphene-Cu system to coalescence together under a continuous corrosion environment, eventually presenting a homogeneous oxidation of Cu and gradual decoupling of graphene-Cu system. This discovery will assist our understanding of the barrier properties of two-dimensional materials and can be extended to other applications related to quality monitoring of grown materials and defects-based chemical modifications.

Fault Detection and Isolation Methods in Subsea Observation Networks.

Subsea observation networks have gradually become the main means of deep-sea exploration. The reliability of the observation network is greatly affected by the severe undersea conditions. This study mainly focuses on theoretical research and the experimental platform verification of high-impedance and open-circuit fault detection for an underwater observation network. With the aid of deep learning, we perform the fault detection and prediction of the network operation. For the high-impedance and open-circuit fault detection of submarine cables, the entire system is modeled and simulated, and the voltage and current values of the operating nodes under different fault types are collected. Numerous calibrated data samples are supervised by a deep learning algorithm, and a fault location system model is built in the laboratory to verify the feasibility and superiority of the scheme. This paper also studies the fault isolation of the observation network, focusing on the communication protocol and the design of the fault isolation system. Experimental results verify the effectiveness of the proposed algorithm for the location and prediction of high-impedance and open-circuit faults, and the feasibility of the fault isolation system has also been verified. Moreover, the proposed methods greatly improve the reliability of undersea observation network systems.

Mesoporous ZnCo2O4/rGO nanocomposites enhancing sodium storage.

In this study, mesoporous ZnCo2O4/rGO nanocomposites were favorably synthesized via a simple solvothermal technique. As a prospective anode material for sodium-ion batteries, the resulting ZnCo2O4/rGO-II nanocomposite exhibited superior electrochemical sodium storage performance with predominant specific capacity, favorable cyclability and ascendant rate capability. For example, an outstanding discharge capacity of 210.5 mAh g-1 was delivered at a current density of 200 mA g-1. Notably, the nanocomposite could yield a discharge capacity of 101.7 mAh g-1 at a current density of 1000 mA g-1 after 500 loops, which certifies its superior capacity retention and predominant cycling stability. The boosted performance of the anode materials is due to the mutual synergistic effect resulting from a combination of the mesoporous ZnCo2O4 nanospheres and conducting reduced graphene oxide nanosheets.

Study on the In Vitro and In Vivo Antibacterial Activity and Biocompatibility of Novel TiN/Ag Multilayers Immobilized onto Biomedical Titanium.

To determine the short- and long-term antibacterial properties of a novel biomedical titanium alloy to ensure excellent biocompatibility of the TiN/Ag multilayers loaded with different doses of Ag+. First, nanosized TiN/Ag multilayers were accumulated onto titanium alloy (Ti-6Al-4V) substrates via multi-arc ion plating. Then, the multilayers were implanted with different doses of silver ions (1×1017 ions/cm², 1×1018 ions/cm², 5×1016 ions/cm², and 5×1017 ions/cm²). Both short- and long-term antibacterial properties against Streptococcus mutans and Staphylococcus aureus were assessed via unique methods. Additionally, the response and behaviors of MC3T3-E1 and L929 cells on the different surfaces were evaluated by a variety of methods through comparison to a normal matched substrate (Ti-6Al-4V). In Vitro and In Vivo analyses revealed that the multilayers containing different doses of Ag ions effectively prevented bacterial adhesion and eliminated the majority of adhered bacteria in the initial period. In addition, the antibacterial activity of each TiN/Ag group improved with time, with the antibacterial rate (Ra) ultimately reaching 99% (antibacterial activity: 1 × 1018 ions/cm² > 5 × 1017 ions/cm² > 1 × 1017 ions/cm² > 5 × 1016 ions/cm²). All of the samples loaded with Ag+ exhibited good compatibility, as well as higher cell proliferation and lower apoptosis than the pure Ti-6Al-4V substrates. Considering both bacteriostasis and biocompatibility, 1 × 1017 ions/cm² and 5 × 1017 ions/cm² are the recommended doses for orthopedic and dental implants. The results indicate that all of the samples loaded with Ag+ possess excellent biocompatibility and antibacterial activity against common bacteria that cause implantation infection. The samples loaded with Ag+ can be implanted into soft and hard growing tissues to greatly improve the survival rate of orthopedic and dental implants.

A Fast Binocular Localisation Method for AUV Docking.

Docking technology plays a critical role in realising the long-time operation of autonomous underwater vehicles (AUVs). In this study, a binocular localisation method for AUV docking is presented. An adaptively weighted OTSU method is developed for feature extraction. The foreground object is extracted precisely without mixing or missing lamps, which is independent of the position of the AUV relative to the station. Moreover, this extraction process is more precise compared to other segmentation methods with a low computational load. The mass centre of each lamp on the binary image is used as matching feature for binocular vision. Using this fast feature matching method, the operation frequency of the binocular localisation method exceeds 10 Hz. Meanwhile, a relative pose estimation method is suggested for instances when the two cameras cannot capture all the lamps. The localisation accuracy of the distance in the heading direction as measured by the proposed binocular vision algorithm was tested at fixed points underwater. A simulation experiment using a ship model has been conducted in a laboratory pool to evaluate the feasibility of the algorithm. The test result demonstrates that the average localisation error is approximately 5 cm and the average relative location error is approximately 2% in the range of 3.6 m. As such, the ship model was successfully guided to the docking station for different lateral deviations.

Transcriptomic analyses reveal molecular mechanisms underlying growth heterosis and weakness of rubber tree seedlings.

BACKGROUND: Breeding rubber tree seedling with growth heterosis is vital for natural rubber production. It is the prerequisites for effectively utilizing growth heterosis to elucidate its molecular mechanisms, but the molecular mechanisms remain poorly understood in rubber tree. To elucidate seedling growth heterosis, we conducted comparative transcriptomic analyses between the two hybrids and their parents. RESULTS: By identifying and comparing differently expressed genes (DEGs), we found that the hybrids (BT 3410 and WC 11) show significantly differential expression profiles from their parents (PR 107 and RRIM 600). In BT 3410-parent triad, 1092 (49.95%) and 1094 (50.05%) DEGs indicated clear underdominance or overdominance, respectively. Whereas in WC 11-parent triad, most DEGs (78.2%, 721) showed low- or high-parent dominance; 160 (17.35%) exhibited expression patterns that are not statistically distinguishable from additivity, and 8 (0.87%) and 33 (3.58%) DEGs exhibited underdominance and overdominance, respectively. Furthermore, some biological processes are differentially regulated between two hybrids. Interestingly, the pathway in response to stimulus is significantly downregulated and metabolic pathways are more highly regulated in BT 3410. CONCLUSIONS: Taken together, the genotypes, transcriptomes and biological pathways (especially, carbohydrate metabolism) are highly divergent between two hybrids, which may be associated with growth heterosis and weakness. Analyzing gene action models in hybrid-parent triads, we propose that overdominance may play important roles on growth heterosis, whereas dominance on hybrid weakness in rubber tree seedlings. These findings bring new insights into our understanding of growth heterosis of rubber tree seedling.