Due to insufficient molecular biology and genetic research on Rosa anemoniflora, this endangered plant has not yet received effective protection. Therefore, the complete chloroplast genome sequence of R. anemoniflora, along with comparative analysis of the chloroplast genomes of related species, is necessary and crucial for reconstructing phylogenetic relationships and developing genetic markers to conserve these species. A series of analyses, including genome structure, GC content, gene number, selection pressure, and nucleotide diversity, were performed by comparing the chloroplast genomes of R. anemoniflora and its relatives. The results indicate that the chloroplast genomes of R. anemoniflora and its close relatives are highly conserved in all genome characteristics, and all protein-coding genes in R. anemoniflora have not experienced significant positive or negative selection pressures. Comparative analysis revealed several variation hotspots, such as the atpH-atpI region, which can serve as a DNA barcode for distinguishing R. anemoniflora from its close relatives. Finally, the results confirmed that R. anemoniflora belongs to Rosa section Synstylae and that R. anemoniflora and its close relatives likely originated from the Fujian and Taiwan regions of China and diverged approximately 3.24 million years ago. This study provides crucial information for future biodiversity conservation and genetic resource management.

Introduction: Coniferous_to_broadleaved forest conversion reshapes soil carbon cycling in coastal sandy ecosystems, yet its regulation on component soil respiration and thermal sensitivity remains poorly quantified. To explore the regulatory effects and underlying mechanisms of such vegetation shift on soil carbon cycling in subtropical coastal sandy lands, we carried out this comparative field study. Methods: We investigated the conversion from Pinus elliottii (coniferous forest) to Eucalyptus urophylla × E. grandis (broadleaved forest) using a paired adjacent plot design and two_year continuous in_situ observations. Key indicators including soil respiration components, litter properties, fine root biomass, microbial activity and soil microclimate were monitored. Results: Results showed that the conversion significantly increased total soil respiration (by 25.52%), root respiration (by 62.74%), and heterotrophic respiration (by 9.01%). This promotion was driven by the coupled effects of improved litter quality (low C/N ratio and lignin content), a sharp increase in fine root biomass (by 272.5%), and enhanced microbial activity. It also notably reduced the temperature sensitivity ( Q ₁₀ from 2.29 to 1.55) of soil respiration, with root respiration becoming nearly temperature_insensitive ( Q ₁₀ =1.25). Additionally, the explanatory power of soil temperature for respiration decreased significantly (from 76% to 37.7%), while the regulatory role of litter quality, fine root biomass, and soil microbial activity became prominent, and soil moisture did not act as a limiting factor for soil respiration throughout the study period. Discussion: This conversion achieves a virtuous cycle of “high carbon turnover and high carbon sequestration”, clarifying the above_belowground coupling mechanism of soil carbon dynamics. Our findings thereby provide important scientific support for the optimization of coastal protection forests and the enhancement of carbon sequestration capacity in fragile coastal ecosystems.

The independent origins of plant parasitism in nematodes offer a classic model for studying the evolution of parasitic adaptations. Using comparative genomics, we analyzed representative nematodes from the superfamilies Aphelenchoidea and Tylenchoidea within the suborder Tylenchina, uncovering the genetic basis of cross-superfamily molecular convergence and lineage-specific divergence. Overall, sequence-level molecular convergence was relatively weak, reflecting dilution of evolutionary contrast by closely related ancestral genetic backgrounds and the diverse genetic mechanisms by which different lineages attain the plant-parasitic phenotype. Nevertheless, these two independently evolved parasitic lineages exhibited a predictable, general-purpose molecular arsenal for breaching host physical and immune barriers. At the metabolic level, the unsaturated fatty acid biosynthesis pathway (ko01040) underwent concordant and significant contraction across plant-parasitic lineages throughout the suborder, suggesting a possible shift toward greater reliance on host-derived lipids, although this remains to be functionally tested. At the sequence level, the two superfamilies displayed strong site-level convergence in core genes including host recognition (GRK, Tr-type G), effector protein folding (PDI), plant nitrogen assimilation (asparagine synthetase), and interfacial stress perception (DOMON, alkaline ceramidase), which may contribute to the molecular framework for breaching parasitic barriers and warrant further experimental validation. Building on this foundation, life-history and niche differentiation drove a dual-track paradigm. The Tylenchoidea lineage, represented by sedentary endoparasites, followed a path of large-scale genome-wide streamlining, with extensive outsourcing and degeneration of autonomous metabolic pathways, highly adapted to the stable internal environment of specialized root feeding sites. In contrast, the migratory parasitic Aphelenchoidea displayed a dual paradigm of conserved genome-wide metabolic versatility coupled with precise micro-level remodeling of stress-resistance networks, which we propose, as candidate hypotheses, may facilitate adaptation to the high-stress aerial environment and multiple hosts through micro-scale remodeling of mitochondrial stress responses, host-lipid utilization, and medium-sensing proteins. This contrast between macro-scale degeneration and micro-scale specialization provides a genomic perspective that may help inform future work on the origin and evolutionary radiation of parasitism in invertebrates.

Bursaphelenchus xylophilus combines strong locomotory capacity with high stress tolerance, and the coordinated action of these two traits underpins its global invasion and dispersal. Yet the molecular mechanisms coupling locomotion to stress tolerance remain poorly understood. Here, we focused on the JIII dispersal-stage juveniles, a life-history stage that simultaneously demands high locomotory output and robust stress resistance. Using weighted gene co-expression network analysis (WGCNA), gene set enrichment analysis (GSEA), and random forest machine learning, we systematically screened for hub genes that may jointly regulate locomotion and stress tolerance, and then functionally validated the candidate target by RNA interference (RNAi). The gene encoding the β subunit of the pyruvate dehydrogenase complex (PDHB) was identified as the core candidate target, positioned at the metabolic hub linking glycolysis to the tricarboxylic acid (TCA) cycle. Silencing of BxPDHB significantly increased pyruvate content (~4.61-fold), markedly reduced ATP levels (~16.30% decrease), drastically decreased head-swing frequency (~50.00% reduction), significantly elevated reactive oxygen species (ROS) levels (~4.26-fold), and decreased survival rate (~26.02% reduction), producing a cascade of substrate accumulation, energy deficiency, impaired locomotion, and exacerbated oxidative stress. These results suggest that PDHB, through its role in the energy output of aerobic respiration, may influence locomotory behavior and antioxidant defense, consistent with a key node linking energy metabolism, locomotion, and oxidative stress. This study highlights the potential hub role of a core energy-metabolism enzyme in the coordinated regulation of locomotion and stress tolerance in B. xylophilus, providing new molecular evidence for understanding its dispersal adaptability. Moreover, as a node that maintains basal energy metabolism across multiple active life stages, PDHB represents a promising candidate molecular target for the development of RNA-based biopesticides delivered via trunk injection or nanocarrier-mediated approaches, with potential application value for the green control of pine wilt disease.

Niche theory is a cornerstone of ecology for understanding species coexistence. However, its application to guide conservation remains challenging. This study focuses on Rosa anemoniflora , a threatened plant endemic to China, and adopts a novel perspective by shifting from traditional interspecific niche comparisons to the analysis of intraspecific variation in niche breadth. We quantified niche breadth across different habitats using a newly developed circular sliding window technique, and then applied correlation, regression, and structural equation modeling to identify key soil factors associated with greater expression of intraspecific niche breadth. Our results indicate that high niche overlap in the herb layer may constrain population regeneration. Notably, soil total potassium (TK) and available potassium (AK) showed contrasting associations with niche breadth: TK was positively correlated, while AK was negatively correlated. This pattern suggests that variation in soil potassium status is closely associated with differences in the realized niche breadth of R. anemoniflora . Our sliding window–based analytical approach provides a methodological pathway for applying niche theory to precision conservation by linking fine-scale environmental variation to intraspecific niche expression. The approach offers a potentially transferable strategy and practical guidance for conserving other threatened species.

Bursaphelenchus xylophilus combines strong locomotory capacity with high stress tolerance, and the coordinated action of these two traits underpins its global invasion and dispersal. Yet the molecular mechanisms coupling locomotion to stress tolerance remain poorly understood. Here, we focused on the JIII dispersal-stage juveniles, a life-history stage that simultaneously demands high locomotory output and robust stress resistance. Using weighted gene co-expression network analysis (WGCNA), gene set enrichment analysis (GSEA), and random forest machine learning, we systematically screened for hub genes that may jointly regulate locomotion and stress tolerance, and then functionally validated the candidate target by RNA interference (RNAi). The gene encoding the β subunit of the pyruvate dehydrogenase complex (PDHB) was identified as the core candidate target, positioned at the metabolic hub linking glycolysis to the tricarboxylic acid (TCA) cycle. Silencing of BxPDHB significantly increased pyruvate content (~4.61-fold), markedly reduced ATP levels (~16.91% decrease), drastically decreased head-swing frequency (~50.00% reduction), significantly elevated reactive oxygen species (ROS) levels (~4.26-fold), and decreased survival rate (~26.02% reduction), producing a cascade of substrate accumulation, energy deficiency, impaired locomotion, and exacerbated oxidative stress. These results indicate that PDHB, by regulating the energy output of aerobic respiration, simultaneously affects locomotory behavior and antioxidant defense, functioning as a key node linking energy metabolism, locomotion, and oxidative stress. This study reveals the hub role of a core energy-metabolism enzyme in the coordinated regulation of locomotion and stress tolerance in B. xylophilus, providing new molecular evidence for understanding its dispersal adaptability. Moreover, as a node that maintains basal energy metabolism across multiple active life stages, PDHB represents a promising candidate molecular target for the development of RNA-based biopesticides delivered via trunk injection or nanocarrier-mediated approaches, with potential application value for the green control of pine wilt disease.