Search Results (321)

Effective and sustainable control strategies for pine wilt disease, caused by the pine wood nematode (Bursaphelenchus xylophilus), are urgently needed, as reliance on conventional chemical nematicides faces increasing limitations. In this study, a new kind of integrated approach is proposed. It pairs microbial fermentation filtrates with the green chemicals arecoline and sodium silicate. The filtrates were obtained from bacterial and fungal strains that were had isolated from Pinus massoniana rhizosphere soil. The nematicidal efficacy of individual and combined treatments was evaluated in vitro, while their ability to induce systemic resistance in P. massoniana seedlings was assessed through defense enzyme assays, malondialdehyde (MDA) content measurement, and defense-related gene expression analysis. Results identified several highly effective combinations, particularly arecoline plus CSZ33 and sodium silicate plus CSUFT-F23, which achieved over 72% control efficacy. These formulations not only showed direct toxicity but also significantly enhanced the plant’s antioxidant capacity and upregulated key defense genes. Furthermore, untargeted metabolomics linked these effects to specific bioactive metabolites in the fermentation filtrates, such as D-glutamic acid. This work demonstrates that hybrid bio-chemical formulations can successfully merge immediate pathogen suppression with long-term host resistance priming, offering a promising, sustainable strategy for the integrated management of pine wilt disease. Full article

The NAC transcription factor superfamily is one of the most prominent plant-specific regulatory gene families, extensively participating in multiple metabolic processes that govern plant growth, tissue development and stress adaptation. Masson pine (Pinus massoniana Lamb.) is a native dominant conifer widely cultivated across South China, whose timber resources possess great exploitation potential in pulp manufacturing and the paper industry. In this study, a total of 98 non-redundant NAC family members were mined at the genome-wide level. Functional validation revealed that PmNAC82, a member belonging to the VND evolutionary subgroup, acts as a core regulatory factor controlling wood formation. Subcellular localization tests confirmed PmNAC82 exclusively resides in the cell nucleus. Heterologous genetic transformation in poplar demonstrated that this gene positively regulates the accumulation of lignin and cellulose. Furthermore, through RT-qPCR, yeast one-hybrid assays, and EMSA, we confirmed that PmNAC82 can bind to the promoters of PtrMYB3, PtrMYB21 and PmCesA7. These findings provide a solid foundation for further investigation into the molecular functions of NAC genes in Masson pine as well as their potential application towards molecular breeding strategies aimed at improving wood quality. Full article

This study aimed to reveal the rhizosphere microbial community structure, carbon–nitrogen–phosphorus (C-N-P) nutrient cycling processes, and functional gene characteristics of Pinus massoniana and Schima superba in mixed forests. Furthermore, we sought to elucidate the microbial mechanisms by which mixed-species afforestation enhances soil quality improvement, providing a theoretical basis in soil microbiology for the cultivation of these mixed forests. The research subjects included pure P. massoniana plantations (CLPs), pure S. superba plantations (CLSs), and individual P. massoniana (HJP) and S. superba (HJS) trees within mixed plantations (HJLs). We collected rhizosphere and bulk soil samples to analyze their physicochemical properties and enzyme activities. Metagenomic sequencing was employed to profile the rhizosphere microbial communities and functional genes involved in C-N-P cycling. Furthermore, by integrating a functional gene co-occurrence network analysis with structural equation modeling (SEM), we systematically elucidated the coupling relationships among the stand types, soil properties, microbial communities, and nutrient cycling. Mixed planting significantly improved soil quality; compared to the CLP and CLS forests, the nitrate nitrogen (NO₃⁻-N) content in the mixed forest soils increased by 121.01% and 120.10% (p < 0.05), and the activity of urease (URE) also significantly increased by 123.99% and 49.56%, respectively. Mixing significantly altered the microbial community structure. In the bacterial community of the mixed forests, the abundance of nitrogen-fixing and potentially phosphorus-solubilizing bacteria from the genera Paraburkholderia and Burkholderia increased. In the fungal community, the arbuscular mycorrhizal fungus Rhizophagus, which possesses a nutrient absorption advantage, exhibited absolute dominance, with its relative abundance ranging from 14.84% to 88.81%. The abundances of genes associated with denitrification and phosphorus starvation regulation were significantly upregulated in the mixed forests; notably, the abundance of phosphorus starvation regulation genes in the HJSs was 18.84% higher than that in the CLSs. A co-occurrence network analysis demonstrated that the proportion of positive correlation edges in the HJP nitrogen cycling network reached as high as 75.0%, and the average degree of the HJS phosphorus cycling network (2.691) surpassed that of the CLSs. The structural equation modeling further revealed that the association strength between the fungi and phosphorus cycling genes in the mixed forests increased to R² = 0.915 (p < 0.01) from R² = 0.213 in the pure forests. This mixed planting practice transforms nutrient cycling from a resource-competitive mode to a microbially synergized mode, thereby forming an efficient endogenous nutrient cycling system. This synergistic rhizosphere microbial effect is a key internal mechanism for overcoming nutrient bottlenecks and should serve as a diagnostic indicator of soil recovery in the ecological restoration of degraded pine forests. Full article

Accurate estimation of forest aboveground biomass (AGB) is pivotal for assessing forest carbon sequestration and informing global change studies. Conventional LiDAR-based AGB estimation approaches primarily rely on height and density metrics, which inadequately characterize the complex three-dimensional (3D) structure of forest canopies. This study developed and evaluated a novel method utilizing voxel-based 3D canopy structural metrics derived from airborne LiDAR (ALS) to improve AGB estimation accuracy across diverse forest types. First, voxel-based metrics (Voxel Canopy Height Model (VCHM), canopy volume, and canopy surface area) were extracted from voxelized point clouds. Their distribution patterns across five forest types (Pinus massoniana, Cunninghamia lanceolata, coniferous, broadleaf, and mixed conifer–broadleaf forests) and their correlations with AGB were systematically examined. The results revealed distinct 3D canopy architectures among forest types, with all three voxel metrics showing highly significant positive correlations with AGB; VCHM demonstrated the strongest association. We then constructed two Random Forest models: a baseline model using traditional metrics only, and an enhanced model integrating both traditional and voxel-based metrics. The 10-fold cross-validation indicated that the model incorporating voxel metrics achieved markedly higher accuracy (R² in 0.490–0.684) than the traditional model (R² in 0.480–0.607), representing a relative improvement of 2.1% to 32.7%. The most substantial gain occurred in structurally complex broadleaf forests. The enhanced model was subsequently applied to generate a wall-to-wall AGB map of the study region, yielding a total estimated AGB stock of 8.36 × 10⁶ t, which exhibited a patchy spatial distribution. Pinus massoniana forests accounted for the largest proportion (57.8%) of the total stock. This study demonstrates that voxel-based 3D canopy metrics can more effectively capture forest structural heterogeneity and substantially improve the accuracy of AGB estimation models, particularly for complex forest stands. The findings provide a significant advancement toward precise, stand-scale forest biomass monitoring founded on detailed 3D structural information. Full article

Pathogenesis-related protein 1 (PR1) plays important roles in plant responses to both biotic and abiotic stresses; however, its role in mediating defense against pine wood nematode in Pinus massoniana remains unclear. In this study, a total of 63 PR1 family members were identified in P. massoniana using bioinformatics approaches and were named PmPR1-1 to PmPR1-63 based on their phylogenetic relationships. Phylogenetic analysis showed that these members were distributed among four of the six subfamilies. Most of the encoded proteins were hydrophilic, with lengths ranging from 131 to 406 amino acids. Their promoter regions contained multiple cis-acting elements associated with phytohormone signaling and stress responses, and some members formed gene clusters on chromosomes 2, 5, and 9. qRT-PCR (quantitative reverse transcription polymerase chain reaction) analysis showed that the clustered genes PmPR1-46, PmPR1-55, PmPR1-56, and PmPR1-61 were significantly upregulated in the early stage of pine wood nematode inoculation in both resistant and susceptible P. massoniana plants, with higher expression levels in resistant plants. Transient overexpression of PmPR1-61 increased SOD and PPO activities as well as proline content while decreasing CAT activity. These results suggest that the PmPR1 family may be involved in the defense response of P. massoniana against pine wood nematode. Among them, PmPR1-55, PmPR1-56, and PmPR1-61 represent candidate resistance genes worthy of further investigation and provide valuable gene resources for elucidating resistance mechanisms and supporting molecular breeding in P. massoniana. Full article

Secondary cell wall (SCW) formation and lignin biosynthesis are critical biological processes that determine wood properties. Masson pine (Pinus massoniana Lamb) is a fast-growing conifer species with significant economic value for the pulp and paper industry. While R2R3-MYB transcription factors are known as master regulators of SCW biosynthesis, the specific R2R3-MYB members regulating lignin formation in Masson pine remain largely uncharacterized. In this study, we identified 317 R2R3-MYB genes in the Masson pine genome. Phylogenetic analysis revealed that PmMYB289, a member of the P20 subgroup, is highly homologous to the Arabidopsis SCW regulators AtMYB52 and AtMYB54. Expression profiling demonstrated that PmMYB289 is predominantly expressed in highly lignified old stems. Transcriptional activation assays confirmed that PmMYB289 lacks autoactivation activity. Subcellular localization analysis revealed that PmMYB289 was localized to the nucleus. Ectopic overexpression of PmMYB289 in tobacco (Nicotiana benthamiana) resulted in dwarfed plant growth, reduced stem diameter, and curled leaves. Molecular analysis of these transgenic lines showed a significant downregulation of most key SCW biosynthetic genes, with the exception of NbPAL1. These findings indicate that PmMYB289 acts as a crucial transcriptional repressor in SCW biosynthesis, providing valuable genetic resources for the molecular breeding of superior Masson pine varieties. Full article

Ubiquitins (Ubs) play a crucial role in plant–pathogen interactions, particularly the RPL40 family, which is essential for protein synthesis. While Pinus massoniana is highly susceptible to pine wilt disease (PWD) caused by Bursaphelenchus xylophilus, the defense mechanisms mediated by RPL40s remain poorly understood. Here, we performed a genome-wide identification of the ubiquitin and ubiquitin-like gene family (PmUBQs) in P. massoniana. We identified 30 PmUBQ genes unevenly distributed across 11 chromosomes, which were classified into six subfamilies based on phylogenetic analysis. An analysis of promoter regions indicated that the PmUBQ genes were enriched with cis-acting elements associated with stress responses, hormone regulation, and development. Specifically, two group II members, PmRPL40-1 and PmRPL40-2, located on chromosomes 12 and 11, respectively, were identified and exhibited distinct responses to B. xylophilus infection in resistant and susceptible P. massoniana. PmRPL40-1 was significantly highly expressed in the 15 days post-inoculation, while PmRPL40-2 was downregulated on day 1 and then upregulated. Moreover, both genes showed peak divergence at 15 days post-inoculation; the expression levels of PmRPL40-1 and PmRPL40-2 in resistant P. massoniana were approximately 1.8- and 3.7-fold higher, respectively, than in susceptible P. massoniana. These patterns suggest that PmRPL40s might be involved in the rapid activation of defense responses and late-stage cell repair. Notably, transient overexpression of PmRPL40-1 in P. massoniana led to a significant 1.6-fold increase in the jasmonic acid (JA) content (p < 0.0001). These findings reveal the key PmUBQ genes and suggest that PmRPL40s contribute to PWD resistance potentially through the modulation of JA signaling, offering potential targets for molecular breeding in P. massoniana. Full article

This study systematically investigated the pretreatment effects of diol-based DESs (deep eutectic solvents) on Pinus massoniana Lamb. (P. massoniana). A diol-based DES system (Choline chloride (ChCl): AlCl₃: BDO) was developed to degrade and disassemble P. massoniana, thereby facilitating saccharification and achieving the utilization of high-value lignin. The DES-based pretreatment achieved a glucan recovery yield of 92.95% and a xylan yield of 71.73% at 130 °C. Meanwhile, the lignin removal yields reached 61.96% at 130 °C, and the lignin recovered from DES fractionation was also preserved well; moreover, the β-O-4′ linkage content was retained at approximately 51.63%. DES was also demonstrated to be promising for promoting cellulose saccharification, lignin fractionation and enzymatic hydrolysis. The preservation mechanism was speculated to involve the introduction of diol -OH groups at the C_α-position of the lignin β-O-4′ structure via etherification. In addition, FT-IR indicated that the main structure of cellulose in P. massoniana remained unchanged after pretreatment. The grafting of diol onto the C_α-position of the β-O-4′ linkages was confirmed by 2D-HSQC, which could inhibit lignin further condensation; ³¹P NMR revealed that the total phenolic -OH content increased significantly and was enhanced by pretreatment, which indicated that methoxy and ether bond groups were reduced. Full article

Masson Pine (Pinus massoniana), an important afforestation species in southern China, is severely threatened by pine wilt disease caused by pine wood nematode (Bursaphelenchus xylophilus, PWN). To differentiate mortality induced by B. xylophilus from that caused by abiotic environmental factors, hyperspectral imaging and needle chlorophyll content were measured and analyzed for the early detection physiological changes in Masson pine seedlings under various environmental stressors. Four-year-old Masson pine seedlings were subjected to PWN inoculation, mechanical injury, drought, and waterlogging treatments. Hyperspectral reflectance and needle chlorophyll content of Masson pine were measured concurrently at 7-day intervals. The results showed that hyperspectral imaging responses varied among the stressors. Both PWN and waterlogging stress induced rapid mortality, with spectral changes observed as early as the 3rd week and reaching statistical significance by the 5th week. Under PWN infection, hyperspectral reflectance increased markedly in the 405–580 nm range, accompanied by a pronounced blue-shift of the red edge position (680–750 nm), while needle chlorophyll content declined sharply from approximately 0.8 mg g⁻¹ to 0.48 mg g⁻¹. Waterlogging stress produced a uniform increase in reflectance within the 500–580 nm range, with the hyperspectral curve gradually flattening, and needle chlorophyll content decreasing from 0.75 mg g⁻¹ to 0.6 mg g⁻¹. Conversely, drought-stressed seedlings exhibited only minor hyperspectral changes and maintained relatively stable chlorophyll levels, demonstrating the inherent drought tolerance of Masson pine. The RF and XGBoost models performed best in fitting the entire process of pine wood nematode infection and waterlogging stress, with all R² values greater than 0.69. The distinct hyperspectral imaging patterns under nematode infection and water-related stresses provide a reliable basis for early diagnosis and monitoring pine wilt disease in Masson pine stands. Full article

Persistent cloud cover and frequent rainfall in subtropical regions throughout the year significantly limit the applicability of optical remote sensing for tree species identification, thereby constraining dynamic forest monitoring and precise management of forest resources. To address this challenge, this study proposes a tree species identification method that integrates multi-source remote sensing temporal features. By combining multi-temporal optical imagery from Sentinel-2 and dual-polarisation Synthetic Aperture Radar (SAR) data from Sentinel-1, we constructed a comprehensive feature set that incorporates spectral, structural, and phenological attributes, including various vegetation indices, backscatter coefficients, and polarimetric decomposition parameters. Through correlation analysis and assessment of temporal feature variability, five distinct integration strategies (T1-T5) were developed to classify six typical subtropical tree species: Pinus massoniana, Pinus elliottii, Acacia, Eucalyptus grandis, Mangrove, and Other hardwoods, using a random forest classifier. The results indicate that the multi-source feature fusion approach significantly outperforms single-source models, with the T5 strategy achieving the highest overall accuracy (OA) of 95.33% and a Kappa coefficient of 0.94. The red-edge vegetation indices and SAR polarimetric features were identified as major contributors to improving the classification accuracy of hardwood species. This study demonstrates that multi-source remote sensing data fusion can effectively mitigate the spatiotemporal constraints of optical imagery, providing a viable solution and technical framework for high-accuracy remote sensing classification in complex subtropical forest environments. Full article

Tannin-boron (TB) treatment is an effective method for enhancing the biological resistance of some types of wood, although knowledge regarding its efficacy as a preservative in a wider range of wood is limited. In this study, we investigated the effects of TB treatment on the mechanical and microscopic properties, and on biological resistance of six types of wood (Pinus massoniana Lamb., Cunninghamia lanceolata (Lamb.) Hook, Pseudotsuga menziesii (Mirb.) Franco, Intsia bijuga (Colebr.) Kuntze, Tectona grandis L. f., and Quercus mongolica Fisch. ex Ledeb.). The results showed that the six types of wood exhibited different boron retention after leaching, with the highest retention rate, 21.85%, observed in P. massoniana. The TB treatment did not significantly alter the original density and compressive strength of the wood, except in the case of I. bijuga, where the compressive strength significantly decreased after treatment. Scanning electron microscopy revealed that TB preservative is attached around the tracheids of softwood, or deposited within the vessels of hardwood. No-choice feeding tests showed that the TB-treated wood exhibited high resistance to Coptotermes formosanus with a maximum weight loss of 2.5%. TB treatment significantly improved the resistance of P. massoniana, C. lanceolata, P. menziesii, and T. grandis to Trametes hirsuta. These results demonstrate the potential usefulness of TB preservatives in different wood types. Full article

Revegetation is recognized as one of the most effective strategies for the ecological restoration of tailings ponds. However, a systematic understanding of how both plant colonization time and plant type shape the microbial functional potential for coupled biogeochemical cycles remains insufficient. Here, we collected 24 samples comprising bare tailings and rhizosphere tailings from four dominant plant species (Miscanthus sinensis, Pinus massoniana, Lespedeza bicolor, Patrinia villosa) colonizing a lead–zinc mine tailings pond to investigate the effects of revegetation on the contents of carbon (C), nitrogen (N) and phosphorus (P) and microbial functional genes related to their cycles. The results showed that revegetation significantly increased the C, N and P contents in the rhizosphere tailings (p < 0.05), and these increased with plant colonization time. Compared with the bare tailings, the contents of C, N and P increased by 1.10 to 4.12 times, 1.06 to 4.84 times and 0.63 to 7.30 times, respectively. Furthermore, revegetation significantly enriches microbial C-, N- and P-cycling genes. The abundance of C fixation, organic degradation, nitrate reduction and organic P mineralization genes in tailings significantly increased after revegetation. Additionally, revegetation substantially enhanced the density, links and average degree of the network of microbial C-, N- and P-cycling genes. Pathway analysis using partial least squares path modeling indicated that revegetation positively affected microbial C-, N- and P-cycling genes, which were regulated by plant type and colonization time. Collectively, these findings suggest that revegetation can substantially enhance the biogeochemical cycling functions of microorganisms in tailings while also promoting their coupling. Full article

Greenhouse gases emitted by humans have exacerbated global climate change. Forests can effectively sequester atmospheric carbon dioxide through photosynthesis, and afforestation has been widely adopted worldwide to mitigate climate change. Cunninghamia lanceolata and Pinus massoniana, as major afforestation tree species, are extensively cultivated in southern China. However, the mechanisms by which climate, topography, biodiversity, forest structure, and forest growth status affect the productivity of these two species remain unclear. This study used forest inventory data from Lishui City combining the Biomod2 model with a structural equation model (SEM) to investigate the differential effects of biotic and abiotic factors on the productivity of the two tree species. The results showed that at the same diameter at breast height (DBH), the biomass of P. massoniana reached 384.67 kg, accounting for 188.75% of that of C. lanceolata (211.07 kg). The dominant climatic factors affecting C. lanceolata and P. massoniana were different; the most important climatic factors affecting C. lanceolata were Bio 17, Bio 15, Bio 05, Bio 08, and Bio 02, while those affecting P. massoniana were Bio 18, Bio 04, and Bio 01. Furthermore, the explanatory power of the structural equation model (SEM) optimized by the Biomod2 model was effectively improved. Biodiversity and forest growth factors were the most important biotic factors affecting C. lanceolata (p < 0.01), while structural diversity and forest growth factors were the most important biotic factors affecting P. massoniana (p < 0.05). Biodiversity and structural diversity exerted divergent effects on C. lanceolata and P. massoniana in different growth stages, exerting negative effects in the early growth stage and positive effects in the late growth stage. These outcomes were jointly driven by the selection effect and niche complementarity. This study recommends the forest management practices should select tree species based on local conditions. Full article

Monitoring spatiotemporal dynamics of aboveground carbon (AGC) storage at the tree species level is crucial for evaluating the ecological impacts of large-scale infrastructure projects and facilitating accurate ecological environmental management. However, existing studies heavily rely on interannual coarse-spatial-resolution forest-type products, leading to significant uncertainties in carbon estimation, particularly in fragmented linear engineering zones. This study integrated Sentinel-1/2 data with a random forest (RF) model to map tree species distribution (overall accuracy = 85.18%; Kappa = 0.8319) and AGC estimation (R² = 0.7057; RMSE = 13.35 Mg ha⁻¹) at a 10 m resolution in the Pinglu Canal Basin from 2019 to 2024. The results revealed a total AGC decline of 16.88% across the watershed. Spatially, the Environmental Impact Area (EIA) functioned as the primary disturbance core (experiencing a 28.91% loss), while the Ecological Buffer Area (EBA) acted as a regional carbon stabilizer. At the species level, while Eucalyptus grandis accounted for the majority of carbon depletion, Pinus massoniana exhibited a resilience-driven rebound in the mid-construction phase. Meanwhile, Litchi chinensis and other native species demonstrated steady gains. Cumulatively, these species-specific carbon gains associated with natural growth and restoration initiatives effectively offset 34.45% of the carbon loss. These findings provide quantitative evidence supporting the potential of green engineering to mitigate the ecological footprint of infrastructure development. This study offers a robust monitoring tool for low-carbon infrastructure and directly supports the United Nations Sustainable Development Goal 15 (SDG 15) related to forest conservation and ecological restoration. Full article

Masson pine (Pinus massoniana Lamb.) is the most widely planted tree species in southern China, playing a critical role in forestry production and reforestation. Understanding the contribution of Masson pine plantations to biodiversity conservation is essential for sustainable land-use policies. We conducted comparative studies to examine the family diversity and composition of ground-dwelling and aerial insects in Masson pine plantations and adjacent natural forests at regional (spanning five forest types across Guangxi, China) and local (at Yachang, Guangxi) scales. We investigated the mechanisms driving the differences in insect community assemblages between the two forest types at the local scale. Our results indicated that aerial insect diversity and composition in Masson pine plantations were comparable to those in natural forests. However, ground-dwelling insects in plantations showed a significant decline in diversity and a notable shift in community composition, with a decrease in highly mobile omnivores (e.g., Drosophilidae and Nitidulidae) and an increase in crawling detritivores (e.g., Blattidae and Gryllidae). These patterns were consistent at both regional and local scales. At the local scale, the shift in ground-dwelling insect community composition was linked to decreased understory tree density (explaining 45.9% of the compositional variation), reduced litter Ca content (29.7%), and increased litter cover (13.5%) in plantations. To enhance ground-dwelling insect diversity in Masson pine plantations, mixed planting with broad-leaved species offers an effective management strategy. This approach both enriches litter nutrients and reduces needle litter accumulation, thereby supporting the recovery of understory vegetation. Full article