Search Results (37)

Background: The phylogenetic placement and chloroplast-inferred maternal relationships of commercial pluot cultivars remain unclear, largely because plastome-level evidence is limited for assessing their affinities with Prunus salicina and Prunus ussuriensis. Although chloroplast genome structure has been well characterized in angiosperms and in several Prunus species, complete plastome resources and comparative genomic evidence for commercial pluot cultivars remain scarce. Methods: Here, we assembled the complete chloroplast genomes of six commercial pluot cultivars and performed comparative genomic, phylogenomic, and divergence time analyses using representative Prunus species. Results: All genomes exhibited the typical circular quadripartite structure and ranged from 157,865 to 158,138 bp in length. Genome organization, GC content, and gene content were highly conserved, whereas the IR regions showed an elevated GC content of approximately 42.6%, owing to rRNA gene enrichment. IR boundary comparison revealed contraction at the IRb/SSC boundary in P. ussuriensis, while pluot cultivars were structurally more similar to P. salicina. In total, 370 SSR loci and four hypervariable regions, namely rpoB–trnC-GCA, petN–psbM, trnV-UAC–trnM-CAU, and trnP-UGG–psaJ, were identified as candidate molecular markers for Prunus germplasm identification and genetic analysis. Phylogenomic analysis resolved four major clades within Prunus and showed that ‘Flavor King’, ‘Flavor Supreme’, and ‘Flavor Queen’ grouped with P. ussuriensis, whereas ‘Flavorosa’, ‘Dinosaur Egg’, and ‘Flavorich’ grouped with P. salicina. Conclusion: Overall, this study provides the first comparative plastome analysis of six commercial pluot cultivars and offers chloroplast-level evidence for their maternal affinities within Prunus, together with useful marker resources for cultivar identification and germplasm evaluation. Full article

Plant detritus plays a pivotal role in regulating soil nutrient dynamics within forest ecosystems. Understanding short-to-medium-term responses of soil-available nitrogen (AN) and phosphorus (AP) to altered detritus inputs is important for forest nutrient management. In this study, we investigated the effects of changing detritus inputs on soil AN and AP in two representative forest types in Northeast China—Korean pine (Pinus koraiensis Siebold et Zucc.) forest (KP) and Aspen (Populus ussuriensis Kom.)−birch (Betula platyphylla Sukaczev) forest (AB). Using the detritus input and removal treatments (DIRTs) method, we established six experimental treatments and measured soil ammonium nitrogen (NH₄⁺-N), soil nitrate nitrogen (NO₃⁻-N), and AP contents monthly from May to October. The results showed that significant differences in NH₄⁺-N, NO₃⁻-N, and AP contents were observed among treatments. Under the six DIRTs, the fluctuation ranges of NH₄⁺-N, NO₃⁻-N, and AP contents in KP soil were 1.16–12.52 mg/kg, 7.34–35.40 mg/kg, and 9.63–31.72 mg/kg, respectively. For AB soil, the fluctuation ranges of the above three nutrients under the six DIRTs were 2.94–13.17 mg/kg, 3.45–28.47 mg/kg, and 1.77–25.60 mg/kg, respectively. Root treatments exerted stronger effects on AN and AP than litter: root exclusion generally reduced NH₄⁺-N but increased NO₃⁻-N and AP, with the direction and magnitude of the response to this treatment varying with month and forest type, whereas litter treatments showed no consistent trends. The soil-available N:P ratio was lower in the KP forest than in the AB forest; root exclusion significantly reduced the N:P ratio in the AB forest but had no significant effect on that in the KP forest. In terms of seasonal dynamics, the study found that AN peaked in May and AP in July. In conclusion, these findings reflect the short-to-medium-term effects of plant detritus, forest type, and month on soil-available nitrogen and phosphorus, providing scientific insights into how detritus changes alter soil nutrients in temperate forests. Full article

Background/Objectives: Eleocharis ussuriensis Zinserl. is a perennial riparian sedge widely distributed in Northeast Asia and a dominant component of freshwater vegetation in South Korea. However, the intraspecific genetic structure of this species across contrasting hydrological habitats remains insufficiently understood. This study aimed to develop novel SSR markers from whole-genome data and investigate genetic variation and population structure among E. ussuriensis populations in South Korea. Methods: Twenty-one novel simple sequence repeat (SSR) markers were developed from whole-genome sequence data and applied to analyze genetic variation in 120 individuals from 6 populations. Genetic diversity, differentiation, and gene flow were estimated using allele-frequency-based metrics, and population genetic structure was further evaluated using spatial information derived from geographic coordinates. Results: A total of 201 alleles were detected, with a mean polymorphism information content (PIC) of 0.759, indicating high marker informativeness. Mean genetic diversity across populations showed observed heterozygosity (Ho = 0.360) and expected heterozygosity (He = 0.281), while multilocus genotype ratios (G/N) ranged from 0.30 to 1.00 among populations. Genetic differentiation was substantial (F_ST = 0.373–0.669; Jost’s D = 0.540–0.997). Mantel tests revealed that genetic differentiation was significantly correlated with geographic distance (r = 0.67, p < 0.001). Both allele-frequency-based and spatially explicit approaches suggested genetic structuring among populations. Conclusions: The results suggest spatial tendencies in genetic structure among populations, reflecting patterns of allele distribution across regions. These findings provide baseline information on genetic variation in E. ussuriensis and may contribute to a better understanding of its ecological dynamics. Full article

Inefficient fertilization practices frequently take place in orchards in Dangshan County, leading to substantial changes in soil properties and pear tree growth. To comprehensively evaluate the long-term impact and identify limiting factors, this study assessed the effects of 30-year fertilization across different soil layers in “Dangshansuli” pear orchards. In May 2020, 30 soil samples were collected from a long-term fertilized plot and an unfertilized sandy control. The analyses focused on the physicochemical properties, mineral elements, heavy metals, chemical compound diversity, and allelopathic effects. The results showed that long-term fertilization significantly reduced soil pH (e.g., from 8.1 to 7.3 in the topsoil) and increased the content of soil organic matter by about 3.7-fold in the 0–20 cm layer. The contents of available potassium, exchangeable calcium, and magnesium in fertilized soil were optimal for pear growth, whereas available iron was deficient. Although fertilization led to the accumulation of heavy metals (Cu, Hg, Ni, Cr, As, Mn), their concentrations remained within national safety limits. The number of chemical compounds detected in fertilized soil was over 40% higher than in the control. Allelopathy tests indicated that 0.18 mmol·L⁻¹ of octadecane strongly inhibited the root growth of “Shanli” (Pyrus ussuriensis Maxim.) tissue-cultured seedlings by more than 50%. These findings provide a scientific basis for optimizing fertilization strategies in “Dangshansuli” pear orchards. Full article

Background/Objectives: Pyrus ussuriensis Maxim. has been cultivated in many regions worldwide. This plant is also regarded as a profitable fruit crop for the development of many food and functional products. There is limited research on the application of the LC-MS associated reaction method for screening active compounds. In this study, we developed an analytical technique employing an ultra-high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) system. Methods: The metabolite annotation procedure was used to interpret and validate data analysis via spectral matching against public databases. Results: As a result, metabolites from P. ussuriensis water and EtOH extracts were identified, and their quantities were further evaluated. The established method was employed to determine antioxidant capacity using a pre-incubation UHPLC-2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, thereby identifying antioxidant ingredients. The antioxidative interference of active constituents was predicted by calculating the decrease in the peak areas of the chemical composition detected in chromatograms between treated and non-treated samples. Furthermore, drug-likeness was also assessed via pharmacokinetics (absorption, distribution, metabolism, and excretion: ADME) evaluation. Conclusions: The online UHPLC-MS-DPPH method would be a powerful tool for the rapid characterization of antioxidant ingredients in plant extracts. The current study highlights the value of P. ussuriensis for improved health benefits. Full article

The genus Pseudobagrus represents a group of economically and ecologically significant freshwater bagrid catfishes in East Asia, yet its taxonomy remains contentious. This study employed the complete mitochondrial genomes of 15 Pseudobagrus species to clarify their phylogenetic relationships. The mitogenomes ranged from 16,526 to 16,647 bp, exhibiting a conserved gene order and significant AT bias (average A + T = 57.85%). All genomes contained 13 protein-coding genes (PCGs), 22 tRNAs, two rRNAs, and a control region. Start codons were predominantly ATG, except for COI (GTG), while stop codons varied among TAA, TAG, and incomplete T--. Codon usage bias favored NNU and NNA codons, and 12 optimal codons were identified in P. albomarginatus. The phylogenetic trees based on concatenated PCGs revealed two major clades. Clade I contained 14 species. Within this clade, P. albomarginatus, P. tenuis, and P. brevicorpus clustered together first, and then this trio grouped with P. ussuriensis. Pseudobagrus trilineatus formed the separate Clade II. These results provide a molecular foundation for species delimitation and systematic revision within Pseudobagrus, supporting the monophyly of the genus while highlighting cryptic diversity and taxonomic complexity. Full article

Through research on the effects of soil and meteorological factors on poplar wood properties, poplar clones with enhanced cold tolerance, drought resistance, and salt–alkali tolerance were selected for large-scale cultivation in the Western Songnen Plain, Northern China. We evaluated wood physical properties (basic density) and anatomical characteristics (annual ring width—RW, vessel number—CNO, vessel lumen area—LA) of 15-year-old Populus simonii × P. nigra, Populus alba × P. berolinensis, P. euramericana N3016 × P. ussuriensis, and Populus pseudo-cathayana × P. deltodides clones in the typical black soil area and saline–alkali land. The results showed that black soil region was more suitable for poplar growth, which was influenced by both soil and meteorological factors. Among soil factors, pH was the primary factor influencing the radial growth of poplar clones, exhibiting a negative correlation for all clones except P. alba × P. berolinensis. Furthermore, P. euramericana N3016 × P. ussuriensis was affected by organic carbon, while P. simonii × P. nigra and P. alba × P. berolinensis were more influenced by potassium. Among climatic factors, basic wood density, annual ring characteristics, and vessel structural parameters in all clones were primarily influenced by wind speed and sunshine, with air temperature having the least effect. Among the four clones, P. alba × P. berolinensis displayed better growth performance (higher RW) and basic wood density (0.29–0.41 g/cm³) at both sites, while P. simonii × P. nigra proved suitable for cold regions. Both clones showing dual adaptability to saline–alkali and black soil environments in Northeast China. Full article

Pseudobagras ussuriensis is a valuable freshwater fish species with enormous breeding potential. To clarify the relationship between the main visceral indices and body weight in this species, 139 cultured individuals were randomly selected to measure body weight and six major organs (namely the intestine, liver, swim bladder, kidney, spleen, and gonadal), and then the causal network of internal organs and body weight of one-year-old P. ussuriensis was analyzed by path analysis, and sex-specific regression models were developed. The results showed that the correlations between body weight and the masses of the intestine, liver, swim bladder, kidney, and gonad were significant, while the spleen mass showed a significant positive correlation with body weight. Path analysis revealed that the direct path coefficients of the intestine, liver, swim bladder, kidney, and gonad on body weight were significant, and that of the spleen was significant. Through regression analysis, multiple linear regression equations were established. Importantly, the swim bladder had the greatest direct effect on body weight in males, whereas the intestine exhibited the strongest direct effect in females. These findings provide valuable insights for the selection and breeding of P. ussuriensis based on visceral indices. Full article

(1) Background: Nitrogen is a key element that is essential for plant growth, and it is absorbed by roots from the soil. Nitrogen stress severely limits forest tree productivity; therefore, elucidating the molecular mechanisms underlying nitrogen stress tolerance in forest trees is critical for sustainable forestry. (2) Methods: Phenotypic analyses of wild-type (WT) Populus ussuriensis (P. ussuriensis) plantlets grown in vitro were carried out at different time points under both normal and low-nitrogen conditions. Transcriptome analyses of roots were performed at 0, 12, 24, 48, 96, and 336 h under low-nitrogen stress via RNA-seq. A gene regulatory network (GRN) for nitrogen-metabolism-associated DEGs was constructed using a three-gene module framework and a bottom-up Gaussian Graphical Model algorithm. (3) Results: WT P. ussuriensis plantlets grown in vitro exhibited a synergistic response characterized by increased root biomass and suppressed shoot growth. Transcriptome analyses identified 8289 DEGs enriched in nitrogen metabolism, ROS scavenging, root development, and phytohormone signaling. A total of 443 differentially expressed transcription factors (TFs) (mainly MYB, AP2/ERF, and bHLH) were detected. A nitrogen-metabolism-associated GRN comprising 60 nodes was established. (4) Conclusions: Transcriptomic data and nitrogen metabolism pathway predictions from this study establish a systematic foundation for investigating molecular adaptation mechanisms in P. ussuriensis roots under nitrogen stress. Full article

Drought stress significantly impairs plant growth and productivity, which triggers complex adaptive responses mediated by diverse gene families. Among these, the TOPLESS (TPL)/TPL-related (TPR) family of transcriptional corepressors plays a crucial role by recruiting epigenetic modifiers through interactions with EAR motif-containing proteins. However, genome-wide studies of this corepressor family and its associated regulatory networks with EAR motif-containing repressors remain limited. This study aimed to characterize the TPL/TPR transcriptional corepressor family in Populus ussuriensis Kom., elucidate their regulatory networks with EAR motif-containing repressors, and validate their functional roles in drought stress adaptation. To this end, we identified 21 TPL/TPR genes in P. ussuriensis (PuTPLs), classified them into five subfamilies, and found they are evolutionarily conserved with Arabidopsis thaliana and Populus trichocarpa, harboring characteristic CTLH and WD40 domains. Given that TPL/TPR proteins are recruited by transcription factors containing repression motifs, we constructed a putative TPL/TPR-EAR motif interaction network representing a core paradigm of negative regulation. Expression profiling under drought stress showed significant upregulation of most PuTPLs in a tissue-specific and temporal manner. Functional validation using transgenic P. ussuriensis lines overexpressing five PuTPLs demonstrated enhanced drought tolerance, evidenced by reduced electrolyte leakage and malondialdehyde content and increased proline accumulation. Our study provides the first comprehensive genome-wide analysis of the TPL/TPR family in P. ussuriensis, establishes a core EAR-mediated negative regulatory network, and validates the critical role of these genes in drought stress adaptation, providing valuable resources for future mechanistic research and breeding of stress-resistant trees. Full article

This study investigated the phylogenetic relationships in the pear calcium-dependent protein kinase (CDPK) pan-gene family and elucidated its role in the resistance to scab disease caused by Venturia nashicola. By integrating data from eight genomic sets from five cultivated pear species, Pyrus bretschneideri, P. ussuriensis, P. sinkiangensis, P pyrifolia, and P. communis, along with P. betulifolia and interspecific hybrids, 63 PyCDPK family members were identified. Among these, P. communis possessed the highest number of CDPK genes, whereas P. bretschneiderilia had the fewest. These genes encode proteins ranging from 459 to 810 amino acids in length, and are predominantly localized to the cell membrane. Six genes, PyCDPK9, PyCDPK11, PyCDPK12, PyCDPK14, PyCDPK16, and PyCDPK19, were classified as core members of the pan-genome, and PyCDPK19 showed evidence of positive selection pressure. Clustering analysis and transcriptomic expression profiling of disease-resistance-related CDPKs identified PyCDPK19 as a key candidate associated with scab resistance. Promoter analysis revealed that the regulatory region of PyCDPK19 contains multiple cis-acting elements involved in defense responses and methyl jasmonate signaling. Transient overexpression of PyCDPK19 in tobacco leaves induced hypersensitive cell necrosis, accompanied by significant increases in hydrogen peroxide (H₂O₂) accumulation and malondialdehyde (MDA) content. Similarly, overexpression in pear fruit callus tissue followed by pathogen inoculation resulted in elevated levels of both H₂O₂ and MDA. Collectively, these findings indicate that PyCDPK19 mediates defense responses through the activation of the reactive oxygen species pathway in both tobacco and pear plants, providing a promising genetic target for enhancing scab resistance in pears. Full article

Drought stress poses a significant threat to tree growth, making the development of drought-resistant species essential for ecological restoration. WRKY transcription factors are critical regulators of plant drought responses; however, the role of WRKY22 in the woody species Populus ussuriensis K. remains unclear. In this study, the PuWRKY22 gene was cloned from P. ussuriensis via homologous cloning and was found to be highly expressed in leaves and responsive to abscisic acid (ABA) signaling. Subcellular localization confirmed that PuWRKY22 is a nuclear protein. Using fluorescein enzyme complementation assays, PuWRKY22 was shown to bind specifically to W-box cis-elements, indicating its function as a transcriptional regulator. Under ABA and osmotic (sorbitol) stress, the seed germination rate, root growth, and biomass of tobacco and Populus davidiana × Populus bolleana strains overexpressing PuWRKY22 were significantly increased. Additionally, these overexpressed strains exhibited a reduction in reactive oxygen species (ROS) accumulation and a decrease in membrane lipid peroxidation. Transcriptomic analyses revealed that PuWRKY22 activates expression of the ABA receptor gene Ptr.PYL4 (Potri.006G104100.v4.1), which regulates stomatal closure to minimize water loss. Consistent with this, stomatal observations and photosynthetic measurements demonstrated that PuWRKY22 enhances drought tolerance by protecting photosystem II and preserving chlorophyll content. Collectively, this study elucidates the molecular mechanism by which PuWRKY22 enhances drought resistance in woody plants through ABA signaling, providing a foundation for breeding drought-tolerant forest species. Full article

Low temperature is a major stress that severely affects tree growth and development. Despite the fact that the molecular mechanisms behind cold tolerance and associated regulatory networks in these trees remain largely unexplored, we conducted a study to examine the overall changes in metabolites and regulatory pathways of Populus ussuriensis kom. when exposed to cold stress, utilizing a comprehensive multi-omics approach. Transcriptomes exposed to cold stress reveal that most of the candidate genes related to the Calvin–Benson–Bassham cycle and flavonoid synthesis were upregulated. Joint analysis revealed that within 6–48 h of low-temperature treatment, differential genes (such as PAL and CHS) in the flavonoid biosynthesis pathway and metabolites (such as quercetin) were significantly upregulated, indicating a positive correlation under short-term stress. However, prolonged treatment (72 h) may trigger metabolic feedback, leading to a decrease in flavonoid content. In addition, the measurements of gas exchange and metabolite assays of P. ussuriensis showed that photosynthetic acclimation led to a change in the sugar accumulation and starch degradation in response to low temperature, indicating that extensive changes occurred due to the cold and improved tolerance in P. ussuriensis. This study provides a new basis for future studies on the molecular mechanism of cold tolerance at the transcriptional and metabolic levels. Full article

As a unique class of plant-specific transcription factors, the GROWTH-REGULATING FACTORs (GRFs) play pivotal roles in regulating plant growth, development, and stress responses. In this study, the woody plant Populus ussuriensis was taken as the research object. Nineteen PuGRFs were identified and classified into six clades, and their potential evolutionary relationships were analyzed. The possible biological functions of PuGRFs were speculated through bioinformatics analysis. Combining real-time fluorescence quantitative PCR, PuGRFs were determined to be actively expressed in young tissues, and there are distinct tissue-specific expressions in the mature tissues of woody plants. We also conducted RT-qPCR of PuGRFs under different abiotic stresses and phytohormone treatments, most of the family members were induced under the treatments of methyl jasmonate (MEJA) and salicylic acid (SA), and we also found that 4 of 19 PuGRFs might participate in abscisic acid (ABA)-mediated osmotic stress in roots. Protein–protein interaction prediction analysis showed that six PuGRFs can interact with two types of growth-regulating interaction factors (GIFs). Further prediction and verification revealed that PuGRF1/2c and PuGRF1/2d, which belong to the same clade and have highly similar sequences, exhibited divergent interaction capabilities with GIFs, indicating evolutionary fine-tuning and functional redundancy within the GRF family. These findings lay a foundation for studying the molecular mechanisms of PuGRFs in P. ussuriensis, suggest that PuGRFs play important roles in responding to hormones and environmental changes, and the potential interaction relationships are worthy of exploration. Full article

In this work, the toxicity level of nano- and microparticles obtained by underwater welding was assessed. The toxicity of nano- and microparticles obtained by underwater welding was evaluated on three types of marine microalgae: Heterosigma akashiwo (Ochrophyta), Porphyridium purpureum (Rhodophyta), and Attheya ussuriensis (Bacillariophyta). The aim was to study the environmental risks associated with the ingress of micro- and nanoparticles of metal oxides into the marine environment. Water samples containing suspensions from wet welding and cutting processes were analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine heavy metal concentrations. Biotesting included evaluation of growth inhibition, cell size change, and membrane potential of microalgae using flow cytometry. The results showed that samples APL-1 and APL-2 (flux-cored wire) were the most toxic, causing concentration-dependent growth inhibition of H. akashiwo and A. ussuriensis (p < 0.0001) as well as membrane depolarization. For P. purpureum, ELc and ELw (coated electrodes) samples stimulated growth, indicating species-specific responses. The stability of the nanoparticles and their bioavailability were found to play a key role in the mechanisms of toxicity. The study highlights the need to control the composition of materials for underwater welding and to develop environmentally friendly technologies. The data obtained are important for predicting the long-term effects of pollution of marine ecosystems by substances formed during underwater welding. Full article