Proteomic insights into adventitious root formation in Larix kaempferi.

The adventitious root formaton (ARF) in excised plant parts is essential for the survival of isolated plant fragments. In this study, we explored the complex mechanisms of ARF in Larix kaempferi by conducting a comprehensive proteomic analysis across three distinct stages: the induction of adventitious root primordia (C1, 0-25 d), the formation of adventitious root primordia (C2, 25-35 d), and the elongation of adventitious roots (C3, 35-45 d). We identified 1976 proteins, with 263 and 156 proteins exhibiting increased abundance in the C2/C1 and C3/C2 transitions, respectively. In contrast, a decrease in the abundance of 106 and 132 proteins suggests a significant demand for metabolic processes during the C2/C1 phase. The abundance of IAA-amino acid hydrolase and S-adenosylmethionine synthase were increased in the C2/C1 phase, underscoring the role of auxin in adventitious root induction. The decrease in abundance of photosynthesis-related proteins during the C2/C1 phase highlights the significance of initial light conditions in adventitious root induction. Moreover, variation in cell wall synthesis and metabolic proteins in the C2/C1 and C3/C2 stages suggests that cell wall metabolism is integral to adventitious root regeneration. Gene Ontology enrichment analysis revealed pathways related to protein modification enzymes, including deubiquitinases and kinases, which are crucial for modulating protein modifications to promote ARF. Furthermore, the increased abundance of antioxidant enzymes, such as peroxidases and glutathione peroxidases, indicates a potential approach for enhancing ARF by supplementing the culture medium with antioxidants. Our study provides insights into metabolic changes during ARF in L. kaempferi, offering strategies to enhance adventitious root regeneration. These findings have the potential to refine plant propagation techniques and expedite breeding processes. SIGNFICANCE: The main challenge in the asexual reproduction technology of Larix kaempferi lies in adventitious root formation (ARF). While numerous studies have concentrated on the efficiency of ARF, proteomic data are currently scarce. In this study, we collected samples from three stages of ARF in L. kaempferi and subsequently performed proteomic analysis. The data generated not only reveal changes in protein abundance but also elucidate key metabolic processes involved in ARF. These insights offer a novel perspective on addressing the challenge of adventurous root regeneration.

Unraveling the Contribution of MulSOS2 in Conferring Salinity Tolerance in Mulberry (Morus atropurpurea Roxb).

Salinity is one of the most serious threats to sustainable agriculture. The Salt Overly Sensitive (SOS) signaling pathway plays an important role in salinity tolerance in plants, and the SOS2 gene plays a critical role in this pathway. Mulberry not only has important economic value but also is an important ecological tree species; however, the roles of the SOS2 gene associated with salt stress have not been reported in mulberry. To gain insight into the response of mulberry to salt stress, SOS2 (designated MulSOS2) was cloned from mulberry (Morus atropurpurea Roxb), and sequence analysis of the amino acids of MulSOS2 showed that it shares some conserved domains with its homologs from other plant species. Our data showed that the MulSOS2 gene was expressed at different levels in different tissues of mulberry, and its expression was induced substantially not only by NaCl but also by ABA. In addition, MulSOS2 was exogenously expressed in Arabidopsis, and the results showed that under salt stress, transgenic MulSOS2 plants accumulated more proline and less malondialdehyde than the wild-type plants and exhibited increased tolerance to salt stress. Moreover, the MulSOS2 gene was transiently overexpressed in mulberry leaves and stably overexpressed in the hairy roots, and similar results were obtained for resistance to salt stress in transgenic mulberry plants. Taken together, the results of this study are helpful to further explore the function of the MulSOS2 gene, which provides a valuable gene for the genetic breeding of salt tolerance in mulberry.

Exploring the role of the LkABCG36 transporter in lignin accumulation.

Lignin is a complex biopolymer formed through the condensation of three monomeric precursors known as monolignols. However, the mechanism underlying lignin precursor transport remains elusive, with uncertainty over whether it occurs through passive diffusion or an active energized process. ATP-binding cassette 36 (ABCG36) plays important roles in abiotic stress resistance. In this study, we investigated the transport functions of LkABCG36 (Larix kaempferi) for lignin precursors and the potential effects of LkABCG36 overexpression in plants. LkABCG36 enhanced the ability of tobacco (Nicotiana tabacum) bright yellow-2 (BY-2) cells to resist monolignol alcohol stress. Furthermore, LkABCG36 overexpression promoted lignin deposition in tobacco plant stem tissue. To understand the underlying mechanism, we measured the BY-2 cell ability to export lignin monomers and the uptake of monolignol precursors in inside-out (inverted) plasma membrane vesicles. We found that the transport of coniferyl and sinapyl alcohols is an ATP-dependent process. Our data suggest that LkABCG36 contributes to lignin accumulation in tobacco stem tissues through a mechanism involving the active transport of lignin precursors to the cell wall. These findings shed light on the lignin biosynthesis process, with important implications for enhancing lignin deposition in plants, potentially leading to improved stress tolerance and biomass production.

Hyposterolactone A, a 3α-Hydroxy Steroidal Lactone from the Deep-Sea-Derived Fungus Hypocrea sp. ZEN14.

Chemical investigation of the deep-sea-derived fungus Hypocrea sp. ZEN14 afforded a new 3α-hydroxy steroidal lactone, hyposterolactone A (1) and 25 known secondary metabolites (2-26). The structure of the new compound was established by detailed spectroscopic analysis, electronic circular dichroism (ECD) calculation as well as a J-based configuration analysis. Compound 10 showed potent cytotoxicity against Huh7 and Jurkat cells with IC50 values of 1.4 µM and 6.7 µM, respectively.

Large-Scale Quantitative Proteomic Analysis during Different Stages of Somatic Embryogenesis in Larix olgensis.

Larix olgensis is an economically important tree species native to northeastern China. The use of somatic embryogenesis (SE) is efficient and enables the rapid production of varieties with desirable qualities. Here, isobaric labeling via tandem mass tags was used to conduct a large-scale quantitative proteomic analysis of proteins in three critically important stages of SE in L. olgensis: the primary embryogenic callus, the single embryo, and the cotyledon embryo. We identified 6269 proteins, including 176 shared differentially expressed proteins across the three groups. Many of these proteins are involved in glycolipid metabolism, hormone response/signal transduction, cell synthesis and differentiation, and water transport; proteins involved in stress resistance and secondary metabolism, as well as transcription factors, play key regulatory roles in SE. The results of this study provide new insights into the key pathways and proteins involved in SE in Larix. Our findings have implications for the expression of totipotency, the preparation of synthetic seeds, and genetic transformation.

Fusion gene 4CL-CCR promotes lignification in tobacco suspension cells.

KEY MESSAGE: The fusion gene 4CL-CCR promotes lignification and activates lignin-related MYB expression in tobacco but inhibits auxin-related gene expression and hinders the auxin absorption of cells. Given the importance of lignin polymers in plant growth and their industrial value, it is necessary to investigate how plants synthesize monolignols and regulate the level of lignin in cell walls. In our previous study, expression of the Populus tomentosa fusion gene 4CL-CCR significantly promoted the production of 4-hydroxycinnamyl alcohols. However, the function of 4CL-CCR in organisms remains poorly understood. In this study, the fusion gene 4CL-CCR was heterologously expressed in tobacco suspension cells. We found that the transgenic suspension cells exhibited lignification earlier. Furthermore, 4CL-CCR significantly reduced the content of phenolic acids and increased the content of aldehydes in the medium, which led to an increase in lignin deposition. Moreover, transcriptome results showed that the genes related to lignin synthesis, such as PAL, 4CL, CCoAOMT and CAD, were significantly upregulated in the 4CL-CCR group. The expression of genes related to auxin, such as ARF3, ARF5 and ARF6, was significantly downregulated. The downregulation of auxin affected the expression of transcription factor MYBs. We hypothesize that the upregulated genes MYB306 and MYB315 are involved in the regulation of cell morphogenesis and lignin biosynthesis and eventually enhance lignification in tobacco suspension cells. Our findings provide insight into the function of 4CL-CCR in lignification and how secondary cell walls are formed in plants.

Transcriptomic Insights into Functions of LkABCG36 and LkABCG40 in Nicotiana tabacum.

ATP-binding cassette transporters (ABC transporters) play crucial physiological roles in plants, such as being involved in the growth and development of organs, nutrient acquisition, response to biotic and abiotic stress, disease resistance, and the interaction of the plant with its environment. The ABCG subfamily of proteins are involved in the process of plant vegetative organ development. In contrast, the functions of the ABCG36 and ABCG40 transporters have received considerably less attention. Here, we investigated changes in the transcriptomic data of the stem tissue of transgenic tobacco (Nicotiana tabacum) with LkABCG36 and LkABCG40 (Larix kaempferi) overexpression, and compared them with those of the wild type (WT). Compared with the WT, we identified 1120 and 318 differentially expressed genes (DEGs) in the LkABCG36 and LkABCG40 groups, respectively. We then annotated the function of the DEGs against the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. The results showed enrichment in cell wall biogenesis and hormone signal transduction functional classes in transgenic LkABCG36 tobacco. In transgenic LkABCG40 tobacco, the enrichment was involved in metabolic and biosynthetic processes, mainly those related to environmental adaptation. In addition, among these DEGs, many auxin-related genes were significantly upregulated in the LkABCG36 group, and we found key genes involved in environmental adaptation in the LkABCG40 group, including an encoding resistance protein and a WRKY transcription factor. These results suggest that LkABCG36 and LkABCG40 play important roles in plant development and environmental adaptation. LkABCG36 may promote plant organ growth and development by increasing auxin transport, whereas LkABCG40 may inhibit the expression of WRKY to improve the resistance of transgenic tobacco. Our results are beneficial to researchers pursuing further study of the functions of ABCG36 and ABCG40.

Free water imaging as a novel biomarker in Wilson's disease: A cross-sectional study.

BACKGROUND: The bi-tensor free water imaging may provide more specific information in detecting microstructural brain tissue alterations than conventional single tensor diffusion tensor imaging. The study aimed to investigate microstructural changes in deep gray matter (DGM) nuclei of Wilson's disease (WD) using a bi-tensor free water imaging and whether the findings correlate with the neurological impairment in WD patients. METHODS: The study included 29 WD patients and 25 controls. Free water and free water corrected fractional anisotropy (FAT) in DGM nuclei of WD patients were calculated. The correlations of free water and FAT with the Unified WD Rating Scale (UWDRS) neurological subscale of WD patients were performed. RESULTS: Free water and FAT values were significantly increased in multiple DGM nuclei of neurological WD patients compared to controls. WD patients with normal appearing on conventional MRI also had significantly higher free water and FAT values in multiple DGM nuclei than controls. Positive correlations were noted between the UWDRS neurological subscores and free water values of the putamen and pontine tegmentum as well as FAT values of the dentate nucleus, red nucleus, and globus pallidus. In addition, the measured free water and FAT values of specific structures also showed a positive correlation with specific clinical symptoms in neurological WD patients, such as dysarthria, parkinsonian signs, tremor, dystonia, and ataxia. CONCLUSIONS: Free water imaging detects microstructural changes in both normal and abnormal appearing DGM nuclei of WD patients. Free water imaging indices were correlated with the severity of neurological impairment in WD patients.

Comparison of guidelines for biological ancillary materials used for the manufacture of gene and cellular therapy products in Asia.

BACKGROUND AIMS: Although biologiocal ancillay materials (AMs) have specific risk associated with their derivations, it plays key role to manufature cell and gene therapy (CGT) products. It is important to understand the regulation relevant to AMs for developers. METHODS: The authors investigated the guidelines and pharmacopeia (hereinafter referred to as "guidelines") for biological AMs used for the manufacture of CGT products in Asia (China, India, Japan, Korea and Taiwan). In addition, the authors benchmarked the relevant guidelines in the United States (US) and European Union (EU). RESULTS AND DISCUSSIONS: The guidelines could be classified into two types based on whether specific AMs are scoped: (i) general guidelines for risk assessment of AMs and (ii) guidelines for specific AMs. The authors compared the risk categories for each type of AM provided in the general guidelines between the US and China and the specific requirements for bovine serum and trypsin in the guidelines of China, Japan, Taiwan, US and EU. The authors further compiled in-depth descriptions of the respective regulations in China, India, Japan, Korea and Taiwan. There is limited availability of some guidelines for specific AMs. Moreover, there are no common requirements established across the surveyed countries and regions. Therefore, the authors suggest a risk assessment approach for AMs with consideration of their biological origin and traceability, production steps applied and ability to control or remove AMs from the final medicinal product over the CGT manufacturing process.

Increased Magnetic Susceptibility in the Deep Gray Matter Nuclei of Wilson's Disease: Have We Been Ignoring Atrophy?

Background: Histopathological studies in Wilson's disease (WD) have revealed increased copper and iron concentrations in the deep gray matter nuclei. However, the commonly used mean bulk susceptibility only reflects the regional metal concentration rather than the total metal content, and regional atrophy may affect the assessment of mean bulk susceptibility. Our study aimed to quantitatively assess the changes of metal concentration and total metal content in deep gray matter nuclei by quantitative susceptibility mapping to distinguish patients with neurological and hepatic WD from healthy controls. Methods: Quantitative susceptibility maps were obtained from 20 patients with neurological WD, 10 patients with hepatic WD, and 25 healthy controls on a 3T magnetic resonance imaging system. Mean bulk susceptibility, volumes, and total susceptibility of deep gray matter nuclei in different groups were compared using a linear regression model. The area under the curve (AUC) was calculated by receiver characteristic curve to analyze the diagnostic capability of mean bulk susceptibility and total susceptibility. Results: Mean bulk susceptibility and total susceptibility of multiple deep gray matter nuclei in patients with WD were higher than those in healthy controls. Compared with patients with hepatic WD, patients with neurological WD had higher mean bulk susceptibility but similar total susceptibility in the head of the caudate nuclei, globus pallidus, and putamen. Mean bulk susceptibility of putamen demonstrated the best diagnostic capability for patients with neurological WD, the AUC was 1, and the sensitivity and specificity were all equal to 1. Total susceptibility of pontine tegmentum was most significant for the diagnosis of patients with hepatic WD, the AUC was 0.848, and the sensitivity and specificity were 0.7 and 0.96, respectively. Conclusion: Brain atrophy may affect the assessment of mean bulk susceptibility in the deep gray matter nuclei of patients with WD, and total susceptibility should be an additional metric for total metal content assessment. Mean bulk susceptibility and total susceptibility of deep gray matter nuclei may be helpful for the early diagnosis of WD.

Pancreaticojejunostomy Conducive to Biological Healing in Minimally Invasive Pancreaticoduodenectomy.

BACKGROUND: Pancreaticojejunostomy, an independent risk factor for pancreatic fistula, is the cause of several postoperative complications of pancreaticoduodenectomy. As suturing in minimally invasive surgery is difficult to perform, more simplified methods are needed to guarantee a safe pancreatic anastomosis. The concept of "biological healing" proposed in recent years has changed the conventional understanding of the anastomosis, which recommends rich blood supply, low tension, and loose sutures in the reconstruction of the pancreatic outflow tract. METHODS: A literature search was conducted in PubMed for articles on pancreaticojejunostomy published between January 2014 and December 2021. After following a due selection process, several techniques developed in accordance with the concept of biological healing that were found suitable for minimally invasive surgery and their related clinical outcomes were described in this review. RESULTS: The incidence of clinically relevant pancreatic fistula associated with the presented techniques did not exceed 15.9%, indicating superior results compared to Cattell-Warren double-layer duct-to-mucosa anastomosis (incidence: approximately 20%). The features and drawbacks of these approaches have been enumerated from the viewpoint of biological healing. CONCLUSIONS: This review described several modified pancreaticojejunostomy techniques with the advantages of a simplified procedure and a lower incidence of pancreatic fistula. Surgeons can choose to apply them in clinical practice to improve patient prognosis.

Perivascular space is associated with brain atrophy in patients with multiple sclerosis.

BACKGROUND: Perivascular space (PVS) is associated with neurodegenerative and neuroimmune diseases. Multiple sclerosis (MS) is traditionally a neuroimmune disease. However, studies show neurodegeneration also plays a vital role in MS. At present, most studies conclude severer PVS in MS is an imaging marker of neuroinflammation, while a 7T MRI study suggests that PVS in MS is associated with neurodegeneration. METHODS: In this study, 82 MS patients (n=82) and 32 healthy controls (n=32) were enrolled. The following indexes were measured: the number, size and distribution of PVS, the PVS score, corpus callosum index (CCI), corpus callosum area (CCA), the ratio of the corpus callosum to the cranium (CCR), aligned third ventricle width (a3VW), and unaligned third ventricle width (u3VW). RESULTS: The PVS score (4 vs. 3, P=0.041), PVSs number (103.280±45.107 vs. 87.625±30.139, P=0.035), and enlarged perivascular spaces (EPVSs) number (9 vs. 1, P<0.001) of MS patients were significantly higher than in the healthy controls. PVSs number (23.5 vs. 13) and EPVSs number (1 vs. 0) in the basal ganglia (BG), and EPVSs number (3 vs. 0) in centrum semiovale (CSO) of MS patients were significantly higher than in the healthy controls, P<0.001. In MS patients, PVS was correlated with age and hypertension but not to the extended disability status scale (EDSS) score and other clinical data. In MS patients, PVS score was correlated with CCA (rs=0.272; P=0.013) and the CCR (rs=0.219; P=0.048), and PVSs number was correlated with CCA (rs=0.255; P=0.021), the correlation disappeared after adjusting hypertension and age. In MS patients in remission, PVSs number was correlated with CCA (rs=0.487; P=0.019), CCR (rs=0.479; P=0.021), and PVS score was correlated with CCA (rs=0.453; P=0.03). After adjustment of hypertension and age, the total number of PVSs was correlated with CCA (rs=0.419; P=0.049). CONCLUSIONS: The PVS load in MS patients was heavier than healthy people, especially in BG and CSO. PVS was not correlated with EDSS in MS patients. The PVS of MS patients was associated with CCA and CCR, and PVSs number was independently related with CCA in MS patients in remission.

Anti-HIV Compounds from the Deep-Sea-Derived Fungus Chaetomium globosum.

Chemical investigation on the deep-sea-derived fungus Chaetomium globosum led to the isolation of nine compounds. By extensive analyses of the 1D and 2D NMR as well as HR-ESI-MS spectra, their structures were elucidated as xylariol A (1), 1,3-dihydro-4,5,6-trihydroxy-7-methylisobenzofuran (2), epicoccone B (3), epicoccolide B (4), chaetoglobosin G (5), chaetoglobosin Fex (6), cochliodone A (7), cochliodone B (8), and chaetoviridin A (9), assorting as four phenolics (1-4), two cytochalosans (5-6), and three azaplilones (7-9). Compounds 1-3 were firstly reported from C. globosum. Under the concentrations of 20 µg/mL, 1, 2, and 3 exhibited potent in vitro anti-HIV activity with the inhibition rates of 70 %, 75 %, and 88 %, respectively.

Glutamate correlates negatively with cognitive theory of mind in schizotypy.

This study showed a negative correlation between the glutamate level in the anterior cingulate cortex and cognitive theory of mind in individuals with high level of schizotypy but not in non-schizotypy individuals.

Metabolic tuning of a stable microbial community in the surface oligotrophic Indian Ocean revealed by integrated meta-omics.

Understanding the mechanisms, structuring microbial communities in oligotrophic ocean surface waters remains a major ecological endeavor. Functional redundancy and metabolic tuning are two mechanisms that have been proposed to shape microbial response to environmental forcing. However, little is known about their roles in the oligotrophic surface ocean due to less integrative characterization of community taxonomy and function. Here, we applied an integrated meta-omics-based approach, from genes to proteins, to investigate the microbial community of the oligotrophic northern Indian Ocean. Insignificant spatial variabilities of both genomic and proteomic compositions indicated a stable microbial community that was dominated by Prochlorococcus, Synechococcus, and SAR11. However, fine tuning of some metabolic functions that are mainly driven by salinity and temperature was observed. Intriguingly, a tuning divergence occurred between metabolic potential and activity in response to different environmental perturbations. Our results indicate that metabolic tuning is an important mechanism for sustaining the stability of microbial communities in oligotrophic oceans. In addition, integrated meta-omics provides a powerful tool to comprehensively understand microbial behavior and function in the ocean. Supplementary Information: The online version contains supplementary material available at 10.1007/s42995-021-00119-6.

Striatal GABA level is associated with sensory integration ability in individuals with low levels of negative schizotypy.

Recent studies suggest that altered gamma-aminobutyric acidergic (GABAergic) function may result in multisensory integration deficits in schizophrenia. However, it is unclear whether the GABA level is abnormal in individuals with high levels of schizotypal traits and how it would correlate with sensory integration ability in these individuals. This study aimed to compare the GABA level between individuals with high and low levels of negative schizotypy, and examine the relationship between GABA levels and sensory integration ability in each group. In vivo GABA+ and N-acetylaspartate (NAA) levels in the striatum were measured using proton magnetic resonance imaging in 19 participants with high levels of negative schizotypy and 21 participants with low levels of negative schizotypy. The Sensory Integration subscale of the abridged version of the Cambridge Neurological Inventory was used. We examined the group differences in GABA+/NAA levels, and the correlation between striatal GABA+/NAA levels and sensory integration ability in each group. The two groups showed comparable levels of in-vivo GABA+/NAA. In-vivo GABA+/NAA levels were negatively correlated with sensory integration score in participants with low levels of negative schizotypy, but not in participants with high levels of negative schizotypy. Our findings indicate that the increased GABA level is correlated with better sensory integration ability in individuals with low levels of negative schizotypy, implicating the role of GABAergic function in multisensory integration. Unlike schizophrenia patients, individuals with high levels of schizotypy do not exhibit any abnormality in their GABAergic system and sensory integration ability.

Systematic Analysis and Biochemical Characterization of the Caffeoyl Shikimate Esterase Gene Family in Poplar.

Caffeoyl shikimate esterase (CSE) hydrolyzes caffeoyl shikimate into caffeate and shikimate in the phenylpropanoid pathway. In this study, we performed a systematic analysis of the CSE gene family and investigated the possible roles of CSE and CSE-like genes in Populus. We conducted a genome-wide analysis of the CSE gene family, including functional and phylogenetic analyses of CSE and CSE-like genes, using the poplar (Populus trichocarpa) genome. Eighteen CSE and CSE-like genes were identified in the Populus genome, and five phylogenetic groups were identified from phylogenetic analysis. CSEs in Group Ia, which were proposed as bona fide CSEs, have probably been lost in most monocots except Oryza sativa. Primary functional classification showed that PoptrCSE1 and PoptrCSE2 had putative function in lignin biosynthesis. In addition, PoptrCSE2, along with PoptrCSE12, might also respond to stress with a function in cell wall biosynthesis. Enzymatic assay of PoptoCSE1 (Populus tomentosa), -2 and -12 showed that PoptoCSE1 and -2 maintained CSE activity. PoptoCSE1 and 2 had similar biochemical properties, tissue expression patterns and subcellular localization. Most of the PoptrCSE-like genes are homologs of AtMAGL (monoacylglycerol lipase) genes in Arabidopsis and may function as MAG lipase in poplar. Our study provides a systematic understanding of this novel gene family and suggests the function of CSE in monolignol biosynthesis in Populus.

Characterization and functional analysis of the Hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) gene family in poplar.

Hydroxycinnamoyl-CoA: shikimate hydroxycinnamoyl transferase (HCT) divides the mass flux to H, G and S units in monolignol biosynthesis and affects lignin content. Ten HCT homologs were identified in the Populus trichocarpa (Torr. & Gray) genome. Both genome duplication and tandem duplication resulted in the expansion of HCT orthologs in Populus. Comprehensive analysis including motif analysis, phylogenetic analysis, expression profiles and co-expression analysis revealed the divergence and putative function of these candidate PoptrHCTs. PoptrHCT1 and 2 were identified as likely involved in lignin biosynthesis. PoptrHCT9 and 10- are likely to be involved in plant development and the response to cold stress. Similar functional divergence was also identified in Populus tomentosa Carr. Enzymatic assay of PtoHCT1 showed that PtoHCT1 was able to synthesize caffeoyl shikimate using caffeoyl-CoA and shikimic acid as substrates.

Genome sequence and evolution of Betula platyphylla.

Betula L. (birch) is a pioneer hardwood tree species with ecological, economic, and evolutionary importance in the Northern Hemisphere. We sequenced the Betula platyphylla genome and assembled the sequences into 14 chromosomes. The Betula genome lacks evidence of recent whole-genome duplication and has the same paleoploidy level as Vitis vinifera and Prunus mume. Phylogenetic analysis of lignin pathway genes coupled with tissue-specific expression patterns provided clues for understanding the formation of higher ratios of syringyl to guaiacyl lignin observed in Betula species. Our transcriptome analysis of leaf tissues under a time-series cold stress experiment revealed the presence of the MEKK1-MKK2-MPK4 cascade and six additional mitogen-activated protein kinases that can be linked to a gene regulatory network involving many transcription factors and cold tolerance genes. Our genomic and transcriptome analyses provide insight into the structures, features, and evolution of the B. platyphylla genome. The chromosome-level genome and gene resources of B. platyphylla obtained in this study will facilitate the identification of important and essential genes governing important traits of trees and genetic improvement of B. platyphylla.