A comprehensive survey across Liaoning Province (China) was conducted to identify the ecological drivers shaping native assemblages of entomopathogenic nematodes (EPNs) and to assess their potential for biocontrol of Holotrichia dionphalia. From 291 soil samples, 28 EPN isolates representing eight species were recovered: Steinernema ceratophorum, S. fetiae, S. longicaudum, S. monticolum, S. populi (newly recorded in the province), S. xinbinense, Heterorhabditis beicherriana, and H. megidis, along with one unidentified species belonging to the Feltiae clade. EPN community structure was primarily shaped by vegetation and altitude, with forest habitats at mid-elevations (100-300 m) supporting the highest species richness. Soil texture, pH, organic matter, and total nitrogen acted as secondary, species-selective filters, revealing clear niche differentiation among taxa. Virulence assays identified S. populi isolates as the most virulent, causing 85-92% mortality at 14 days with 800 IJs/larva, followed by S. longicaudum isolates (67-73%). These findings expand the known distribution of native EPNs in Northeast China, clarify the ecological filters underlying their occurrence, and identify promising native EPN populations for region-specific biocontrol of H. dionphalia.
Larix olgensis, a keystone timber species in Northeast China, is increasingly threatened by Neofusicoccum laricinum-induced shoot blight, a devastating disease that compromises forest health and necessitates sustainable management strategies. Here, we demonstrate that the endophytic bacterium Bacillus amyloliquefaciens JL54 elicits multifaceted defense responses in L. olgensis, enhancing resistance to pathogen infection. Greenhouse assays revealed that JL54 pretreatment reduced disease incidence by 12.5% and achieved 43.75% control efficacy while maintaining host vigor. Histochemical analyses identified JL54-induced rapid hydrogen peroxide (H2O2) accumulation, extensive lignin deposition, and localized programmed cell death (PCD), indicative of a primed immune response. Transcriptomic analyses uncovered distinct temporal defense patterns: early-stage responses (0 h post-inoculation) were characterized by upregulation of cutin, suberin, and wax biosynthesis pathways, reinforcing physical barriers, whereas late-stage responses (12 h post-inoculation) were dominated by ribosome- and proteostasis-related pathways (e.g., heat shock proteins [HSPs], glutathione S-transferases [GSTs]) to mitigate cellular damage. Biochemical assays corroborated these findings, with JL54 colonization reducing membrane lipid peroxidation (27.2% decrease in malondialdehyde content) and significantly elevating the activity of key defense enzymes, including peroxidase (POD), phenylalanine ammonia-lyase (PAL), and GST. Phytohormone profiling implicated jasmonic acid (JA) as the central mediator of induced systemic resistance (ISR), with JL54-potentiated JA signaling preceding pathogen containment. Collectively, these results demonstrate that JL54 contributes to a coordinated defense strategy in L. olgensis, integrating structural reinforcement (cuticle/lignin), oxidative stress management, and JA-mediated immune priming. These insights advance the understanding of endophyte-conferred resistance in conifers and highlight JL54’s potential as a biocontrol agent for sustainable forestry.
Cistanche Herba (Rou Cong Rong), a critically endangered edible tonic and medicinal plant, is traditionally valued for its nephroprotective and kidney-yang tonifying properties. However, wild populations are declining due to habitat loss, overharvesting, and increasing market demand, leading to widespread adulteration in commercial supplies. Conventional authentication methods, such as morphological examination, photochemical profiling, and ITS/ITS2 barcoding, often fail with processed materials due to DNA degradation. To overcome these limitations, we developed a high-throughput single-nucleotide polymorphism (SNP) genotyping platform that integrates multiplex PCR with MALDI-TOF mass spectrometry, targeting validated nuclear ITS and chloroplast-encoded ribosomal protein large subunit 16 (rpl16) loci. The assay utilizes four diagnostic SNPs specific to C. deserticola, allowing unambiguous differentiation from six adulterants. It demonstrates high sensitivity, detecting 0.07% genomic DNA (6.8 pg/μL) in mixed samples and 1% C. deserticola powder in dried tissue mixture. When validated on 27 dried specimens, the method showed 100% concordance with Sanger sequencing while reducing the total analysis time to approximately 10 hours. By overcoming the resolution limitations of traditional techniques, this approach provides a rapid and scalable solution to combat herbal substitution, support CITES compliance, ensure the integrity of functional foods and traditional medicines.
Aims:β diversity reflects the differences in species composition among communities,serving as a key indicator linking local and regional biodiversity while characterizing spatial distribution patterns of species.In this study,using data from a large forest observation network in the Xiaoxing'an Mountains,we disentangled the patterns,components,and influencing factors of forest β diversity,aiming to provide a scientific basis for biodiversity conservation in this region. Methods:Using the Podani partitioning method,we decomposed β diversity to assess the relative contributions of species replacement and richness difference.We further quantified the local contribution to β diversity(LCBD)and the species contribution to β diversity(SCBD)to identify ecologically unique sites and key species.In addition,regression and variance partitioning analyses were applied to evaluate the relative effects of environmental,spatial and human disturbance factors on community composition,thereby uncovering the ecological mechanisms underlying forest community assembly and biodiversity patterns. Results:(1)Species replacement was the dominant process driving community dissimilarity across the study area.(2)The SCBD values ranged from 0.002％to 21.918％,with Betula platyphylla contributing the most and Populus suaveolens the least.Species with higher SCBD values largely overlapped with the dominant tree species in the region.(3)LCBD values ranged from 0.537％to 2.677％.Plots with higher species richness exhibited higher LCBD values,with southeastern sites generally having greater LCBD values than those in the northwestern.(4)Climatic factors were identified as the primary drivers of LCBD variation.The interaction between climate,spatial,topographic,and human disturbance variables influenced water availability and habitat heterogeneity,thereby indirectly shaping species spatial distribution patterns. Conclusion:Our findings reveal the spatial patterns and ecological drivers of forest β diversity in the Xiaoxing'an Mountains,highlight key regions and species essential for maintaining β diversity,and provide scientific evidence for forest ecosystem management and biodiversity conservation in this region.
Botryosphaeria dothidea is a destructive pathogen responsible for poplar canker, a disease that severely damages poplar trees by inducing stem lesions, growth inhibition, and eventual tree death, thereby causing substantial economic losses in forestry. Although conventional chemical fungicides are effective, their use poses significant environmental and health concerns, highlighting the need for safer biological control strategies. This study investigated the potential of Streptomyces spiroverticillatus, an antagonistic bacterium, to induce resistance in poplar against B. dothidea. Treatment with the cell-free supernatant (CFS) of S. spiroverticillatus markedly enhanced key defense-related physiological and biochemical responses in poplar leaves. Biochemical assays revealed that treated plants exhibited a 20% increase in total phenolics, a 37% rise in flavonoids, and a 40%–62% elevation in lignin content compared with controls. Furthermore, the activities of phenylalanine ammonia-lyase (PAL) and chitinase—enzymes critical for antimicrobial compound biosynthesis and fungal cell wall degradation—increased by 90% and 28%, respectively. Field trials confirmed the biocontrol efficacy of S. spiroverticillatus, reducing disease incidence by 61.17% (preventive) and 71.29% (curative), with corresponding disease reduction rates of 46.26% and 54.83%, respectively. These results outperformed carbendazim treatments, which showed preventive and curative efficacies of 49.97% and 50.04%, and disease reduction rates of 34.18% and 38.42%, respectively. These findings demonstrate that S. spiroverticillatus activates the innate defense mechanisms of poplar, stimulates the accumulation of antimicrobial metabolites and strengthens resistance against B. dothidea. This study identifies S. spiroverticillatus as a promising and environmentally sustainable biocontrol agent for the effective management of poplar canker.
