Search Results (720)

Global trade facilitates multiple introductions of alien species, yet the role of genetic admixture between divergent lineages in driving invasion success remains debated. Here, we address this question by analyzing dynamic genetic changes across invasion stages in the dioecious weed Amaranthus palmeri, introduced to China from North and South America. Combining chloroplast phylogeography with nuclear genetic analyses, we systematically investigated genetic changes in populations at casual, naturalized, invasive, and dispersal stages. Initial casual populations originated from distinct North and South American lineages, but all established populations (naturalized, invasive, dispersal) retained only North American haplotypes. South American genetic introgression decreased progressively during invasion (from 34% in naturalized to 3% in dispersal populations), accompanied by declining inbreeding coefficients. Established populations exhibited high inter-population crosses within the North American lineage (54–60%), maintaining genetic diversity and overcoming bottlenecks. Our findings demonstrate that invasion success in A. palmeri may be driven by gene flow within the North American lineage, rather than admixture between divergent lineages. These findings enhance our understanding of the genetic mechanisms underpinning plant invasions, highlighting lineage-specific management as a critical strategy for controlling invasive populations. Full article

To identify the root-knot nematodes (RKNs) infecting onions in Yuanmou County, Yunnan Province, morphological and molecular biological techniques were used. Observation of their life cycle and pathogenicity was conducted through artificial inoculation experiments in a greenhouse. The results show that the morphological characteristics and measurement data of the second-stage juveniles (J2s) and females of RKNs infecting onion roots are highly consistent with those of Meloidogyne graminicola (M. graminicola). Sequence alignment of the mitochondrial DNA (mtDNA) COXI region and 28S rDNA D2-D3 region revealed sequence similarities of 99.51–100.00% and 99.48–99.61%, respectively, compared with M. graminicola sequences from GenBank. The specific primers Mg-F3/Mg-R2 reliably amplified a characteristic 369 bp band. Inoculation experiments confirmed that the pathogen can complete its entire life cycle (approximately 26 days (ds)) on the roots of healthy onion seedlings, inducing typical root-knot symptoms and females. In conclusion, the pathogen was identified as M. graminicola, which is the first report of M. graminicola infecting onions in China. This study provides important theoretical support for the molecular diagnosis of onion root-knot nematode disease and the green control of Allium L. vegetables in China. Full article

(1) Background: Tolypocladium spp. are fungi known for producing cyclosporin A and their ability to infect insects. However, their pathogenicity against the lepidopteran pest Plutella xylostella has not been previously reported. (2) Methods: Four Tolypocladium strains were isolated from soil and identified through morphological and phylogenetic analyses (ITS, gene sequencing). Growth rates, sporulation capacity, and stress tolerance (45 °C heat, UV) were evaluated. Pathogenicity was assessed via larval bioassays, and immune responses were analyzed by quantifying Toll pathway gene expression and enzyme activities (PO, CAT, POD, GSTs, CarE, AChE) from 24 to 96 h post-inoculation. (3) Results: Strains N8-SF-04092 and O1/O2/O3-SF-04630/04927/04931 were identified as Tolypocladium cylindrosporum and Tolypocladium inflatum, respectively. Strain O2 showed the highest growth rate (p < 0.05), while O3 and N8 exhibited superior sporulation (>7 × 10⁵ spores/mm²). N8 also demonstrated notable thermotolerance. In pathogenicity assays, O1, O3, and N8 caused 98.3%, 93.3%, and 96.7% larval mortality, respectively, with LT₅₀ values (3.89–4.45 days) significantly lower than O2 (p < 0.05). Immune gene expression in P. xylostella was transiently activated at 24 h but suppressed from 48 to 96 h by N8 (p < 0.05), while O1 induced partial activation at 24 h and 96 h but suppression at 48 h and 72 h. Protective enzymes (PO, CAT) were initially upregulated (24–48 h) but inhibited after 72 h (p < 0.01). POD activity showed opposing trends between O1 (initially activated then suppressed) and N8 (initially suppressed then activated). Detoxification enzymes (GSTs, CarE, AchE) were predominantly suppressed, except for GSTs, which increased at 72–96 h. (4) Conclusions: Strains O1 and N8 exhibit high virulence against P. xylostella by disrupting immune responses through dynamic modulation of Toll pathway genes and enzyme activities. The thermotolerance of strain N8 further enhances its promising biocontrol agent for field application. Full article

Long non-coding RNAs (lncRNAs) are emerging as crucial regulators of various biological processes in plants, including development, stress responses, and pathogen defense. Advances in multi-omics sequencing analysis and molecular biology methods have significantly expanded our understanding of the plant lncRNA landscape, revealing novel lncRNAs across diverse species. In this review, we provided an overview of the essential roles of lncRNAs in multilevel regulatory functions in plant growth, development, and stress responses. Moreover, we bridged the module network among these different conditions. One of the most important functions of lncRNA is gene expression regulation. Thus, we summarized the plant lncRNAs acting in cis/trans and as endogenous target mimics (eTMs) to influence the expression of target genes in transcription and post-transcription regulation. This review also sheds light on several application values in agricultural production and development of plant-specific databases and bioinformatic tools. These datasets facilitated the exploration of lncRNA function, enabling the identification of their expression patterns, phylogenetic relationships, and molecular interactions. As research progresses, multi-omics approaches will provide deeper insights into the regulatory mechanisms of lncRNAs, offering promising strategies for enhancing crop resilience and productivity in response to climate change. Full article

Herbivore-induced plant volatiles (HIPVs) are well known for their roles in herbivore deterrence and attraction of natural enemies, but their direct impact on insect reproduction remains largely unexplored. In this study, we provide novel evidence that two representative HIPVs, 2-heptanol and α-cedrene, exert opposing effects on the reproduction of Chilo suppressalis, a major rice pest. While both volatiles repelled adults, α-cedrene unexpectedly enhanced oviposition, whereas 2-heptanol significantly suppressed egg laying. To examine these effects, we conducted oviposition assays, preoviposition and longevity tests, combined with qPCR and transcriptome analyses to explore underlying molecular responses. Mechanistically, α-cedrene upregulated Kr-h1, a gene linked to juvenile hormone signaling and vitellogenesis, promoting reproductive investment. Transcriptomic profiling revealed divergent molecular responses: α-cedrene activated reproductive pathways, whereas 2-heptanol induced stress- and immune-related genes, suggesting a trade-off between stress defense and reproduction. These findings demonstrate that HIPVs can exert compound-specific reproductive effects beyond repellency. This work fills a key knowledge gap and highlights the potential of HIPVs as precision tools in pest management strategies that exploit behavioral and physiological vulnerabilities beyond repellency. Full article

Global warming and anthropogenic climate change are projected to expand the geographic distribution and population abundance of ectothermic species and exacerbate the biological invasion of exotic species. DNA methylation, as a reversible epigenetic modification, could provide a putative link between the phenotypic plasticity of invasive species and environmental temperature variations. We assessed and interpreted the epigenetic mechanisms of invasive and indigenous species’ differential tolerance to thermal stress through the invasive species Bemisia tabaci Mediterranean (MED) and the indigenous species Bemisia tabaci AsiaII3. We examine their thermal tolerance following exposure to heat and cold stress. We found that MED exhibits higher thermal resistance than AsiaII3 under heat stress. The fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) results proved that the increased thermal tolerance in MED is closely related to DNA methylation changes, other than genetic variation. Furthermore, the quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting analysis of DNA methyltransferases (Dnmts) suggested that increased expression of Dnmt3 regulates the higher thermal tolerance of female MED adults. A mechanism is revealed whereby DNA methylation enhances thermal tolerance in invasive species. Our results show that the Dnmt-mediated regulation mechanism is particularly significant for understanding invasive species’ successful invasion and rapid adaptation under global warming, providing new potential targets for controlling invasive species worldwide. Full article

Disparities in the functional classification of secretory genes among aphid taxa may be attributed to variations in coding sequences and gene expression profiles. However, the driving factors that regulate sequence evolution remain unclear. This study aimed to investigate the differences in coding sequences and expression patterns of secretory genes between the rose grain aphid (Metopolophium dirhodum) and the pea aphid (Acrythosiphon pisum), with a particular focus on their roles in evolutionary adaptations and functional diversity. The study involved the rearing of aphids, RNA extraction, de novo transcriptome assembly, functional annotation, secretory protein prediction, and comparative analysis of coding sequences and expression patterns across various functional categories using bioinformatics tools. The results revealed that metabolic genes exhibited greater coding sequence divergence, indicating the influence of positive selection. Moreover, significant expression divergence was noted among functional categories, particularly in metabolic and genetic information processing genes, which exhibited higher variability. This study enhances our understanding of the molecular mechanisms that contribute to phenotypic and genetic diversity among aphid species. This study elucidates the relationship between variations in coding sequences and differences in gene expression among functional categories, thereby establishing a foundation for future studies on gene evolution in response to environmental pressures. Full article

Grapholita molesta is a globally significant fruit pest. Females achieve maximal reproductive output through efficient sperm utilization following a single copulation. Post-mating maturation of eupyrene sperm is a critical step in reproductive success. Here, we report that a male accessory gland-derived serine protease (named GmAGSP1) is essential for this process. GmAGSP1 was only distantly related to other identified sperm-activating SPs, and its transcript was highly expressed in the AG at 48 h after emergence. RNAi-mediated knockdown of GmAGSP1 in males did not affect courtship rate, copulation duration, or mating frequency, whereas male fertility decreased significantly. Mating with GmAGSP1-knockdown males markedly impaired eupyrene sperm maturation in the spermatophores, with phenotypes including failure of eupyrene sperm bundles to dissociate normally and marked reduction in viability of the dissociated eupyrene sperm. Finally, untargeted metabolomic analysis preliminarily demonstrated marked alterations in multiple metabolic pathways within the spermatophore following mating with GmAGSP1-knockdown males. This study advances our understanding of the regulatory mechanism of “sperm activation in the spermatophore’s metabolic microenvironment mediated by male AG-derived SP” while providing critical insights for the development of novel genetic control strategies targeting G. molesta. Full article

The parasitoid wasp Dolichogenidea gelechiidivoris is a key koinobiont solitary endoparasitoid of the invasive agricultural pest Tuta absoluta. This study investigates both the morphological and molecular foundations of sex-specific olfactory differentiation in this species. Morphological analysis revealed that males possess significantly longer antennae (2880.8 ± 20.36 μm) than females (2137.23 ± 43.47 μm), demonstrating pronounced sexual dimorphism. Scanning electron microscopy identified similar sensilla types on both sexes, but differences existed in the length and diameter of specific sensilla. Transcriptomic analysis of adult antennae uncovered molecular differentiation, identifying 11 odorant-binding proteins (OBPs) and 20 odorant receptors (ORs), with 27 chemosensory genes upregulated in females and 4 enriched in males. Integrating morphological and molecular evidence demonstrates complementary sexual specialization in the olfactory apparatus of D. gelechiidivoris. Linking these findings to the potential functions of different sensilla types, as discussed in the context of prior research, provides crucial insights into the sex-specific use of volatile cues. These findings provide critical insights into the use of volatile signals in this highly relevant species for biological control targeting T. absoluta. Full article

Larvae of Episyrphus balteatus De Geer (Diptera: Syrphidae) are important natural enemies of common agricultural pests such as aphids (Hemiptera: Aphididae). This well-known aphidophagous flower fly is used as a biological control agent. The predatory functional responses, control efficacy, and oviposition and predatory preferences of E. balteatus against Aphis craccivora Koch, Myzus persicae Sulzer, and Megoura crassicauda Mordvilko were systematically determined through controlled laboratory experiments. The best functional response model of both second- and third-instar E. balteatus larvae to these three aphid species was the Holling type III model, except for the third-instar larvae to A. craccivora, for which the Holling type II model was superior. The A. craccivora population decline rates for ratios of 1:500 and 1:1000 were 94.67% and 100.00% on day 12 after inoculation; the M. persicae population decline rates for ratios of 1:2000 and 1:4000 reached 96.67% and 95.42% by day 12, and the M. crassicauda population at a ratio of 1:250 was completely eliminated by day 9, achieving a 100.00% population decline rate. The oviposition and predatory preferences of E. balteatus were consistent, in that it preferred M. crassicauda for oviposition and had a positive predatory preference for this aphid species. These results provide scientific evidence for the biological control strategy of E. balteatus against these aphids. Full article

“Rundao118” is a glyphosate-resistant rice; it contains both endogenous wild and mutated 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) genes. Conventional qualitative and quantitative detection methods face significant challenges for direct analysis. Here, we describe five detection methods for identifying EPSPS mutations in this rice line: (1) polymerase chain reaction (PCR) amplification-based Sanger sequencing, (2) next-generation sequencing (NGS) based on PCR amplification, (3) allele-specific PCR (AS-PCR), (4) real-time fluorescent quantitative PCR (qPCR), and (5) blocker displacement amplification (BDA). All five methods effectively identified EPSPS mutations, with the following detection sensitivities: Sanger, 10%; NGS, 1%; AS-PCR, 0.05%; qPCR, 0.01%; and BDA, 0.1%. Among these, the Sanger, NGS, and BDA methods excelled at the rapid identification of single-nucleotide mutations, making them suitable for precise mutation site characterization and identification. In contrast, the AS-PCR and qPCR methods were more appropriate for large-scale rapid screening of known mutation sites. The detection systems established in this study provide a comprehensive technical solution for rapid identification of EPSPS mutations in glyphosate-resistant rice. These methods not only enable accurate determination of mutation sequences but also effectively trace mutation origins, offering crucial technical support for both safety regulations and intellectual property protection. Full article

Root rot is one of the most serious diseases affecting Astragalus membranaceus, significantly reducing its yield and quality. This study focused on root rot in Astragalus membranaceus var. mongholicus. Pathogenic fungi were isolated and identified. The pathogenicity of seven strains of pathogenic fungi was verified according to Koch’s postulates. The inhibitory effects of eight classic fungicides and nine strains of biocontrol agents on the pathogenic fungi were determined using the mycelial growth rate method. Through morphological and ITS phylogenetic analyses, strains CDF5, CDF6, and CDF7 were identified as Fusarium oxysporum, while strains CDF1, CDF2, CDF3, and CDF4 were identified as Fusarium solani. Indoor virulence tests showed that, among the eight tested fungicides, carbendazim exhibited the strongest inhibitory effect on the mycelial growth of both F. oxysporum and F. solani, with a half-maximal effective concentration (EC₅₀) value of (0.44 ± 0.24) mg/mL, making it a highly promising chemical agent for the control of A. membranaceus var. mongholicus root rot. Among the nine biocontrol agents, KRS006 showed the best inhibitory effect against the seven pathogenic strains, with an inhibition rate ranging from 42.57% to 55.51%, and it can be considered a candidate strain for biological control. This study identified the biocontrol strain KRS006 and the chemical fungicide carbendazim as promising core agents for the biological and chemical control of A. membranaceus var. mongholicus root rot, respectively, providing a theoretical foundation for establishing a dual biocontrol–chemical control strategy. Based on the excellent performance of the biocontrol bacteria and fungicides in the pathogen control tests, future research should focus on field trials to verify the synergistic effect of this integrated control strategy and clarify the interaction mechanism between the antibacterial metabolites produced by the biocontrol bacteria KRS006 and carbendazim. Additionally, continuous monitoring of the evolution of Fusarium spp. resistance to carbendazim is critical to ensure the long-term sustainability of the integrated control system. Full article

Aphelenchoides besseyi is considered a highly prevalent facultative plant-parasitic nematode and has a significant impact on various economically important crops globally. Due to the lack of knowledge on the efficacy of various management techniques, A. besseyi is still challenging to control in the open field. The present investigation successfully shed light on some significant new points, including the following: (1) A. besseyi was confirmed inside all soybean tissues—including roots, stems, leaves, and seeds—indicating its endoparasitic nature and its strong ability to reach the upper foliar system where it causes green stem and foliar retention syndrome (GSFR) symptoms; (2) inoculated plants exhibited reduced vegetative growth parameters, as non-inoculated control soybean plants showed higher values of plant height (PH), fresh root weight (FRW), and fresh shoot weight (FSW) compared to inoculated plants; (3) Yudou 29 was identified as highly resistant to A. besseyi, as results from the resistance screening assay among different Chinese soybean cultivars confirmed its strong resistance under natural field infestation conditions; and (4) soybean seeds may act as inoculum sources of A. besseyi, highlighting the need to develop more effective control measures to prevent or limit nematode dissemination through seed transmission. Full article

A system of field protective forest belts (FPFBs) was created in the middle of the 20th century in Southern Dobrudzha (Northern Bulgaria) to reduce wind erosion, improve soil moisture storage, and increase agricultural crop yields. Since 2020, prolonged climatic drought during growing seasons and the advanced age of trees have adversely impacted the health status of planted species and resulted in the decline and dieback of the FPFBs. Physiologically stressed trees have become less able to resist pests, such as insects and diseases. In this work, an original new methodology for the integrated assessment of the condition of FPFBs and their protective capacity is presented. The presented methods include the assessment of structural and functional characteristics, as well as the health status of the dominant tree species. Five indicators were identified that, to the greatest extent, present the ability of forest belts to perform their protective functions. Each indicator was evaluated separately, and then an overlay analysis was applied to generate an integrated assessment of the condition of individual forest belts. Three groups of FPFBs were differentiated according to their condition: in good condition, in moderate condition, and in bad condition. The methodology was successfully tested in Southern Dobrudzha, but it could be applied to other regions in Bulgaria where FPFBs were planted, regardless of their location, composition, origin, and age. This methodological approach could be transferred to other countries after adapting to their geo-ecological and agroforest specifics. The methodological approach is an informative and useful tool to support decision-making about FPFB management, as well as the proactive planning of necessary forestry activities for the reconstruction of degraded belts. Full article