Abstract:

Lepidopteran insects, as major agricultural pests, engage in a complex molecular dialogue with their host plants. Their oral secretions (OS), a mixture of saliva from salivary glands and digestive fluids from the gut, are introduced into plant tissue during larval feeding, thereby influencing plant defense responses. Through long-term co-evolution with host plants, lepidopteran insects have been able to produce OS containing a sophisticated array of components, including both elicitors that activate plant defenses and effectors that suppress them. This review systematically summarizes recent research advances in the interaction systems between lepidopteran insects and plants, with a focus on the composition, functions, and mechanisms of action of salivary proteins. Additionally, it highlights current limitations in research methodologies, such as techniques for identifying salivary proteins, understanding transmembrane transport mechanisms, and assessing functional conservation. Future studies should integrate multi-omics technologies, cross-species comparisons, and multi-host plant systems to further elucidate the evolutionary and functional diversity of lepidopteran salivary proteins, providing a theoretical foundation for developing novel pest control strategies.

Abstract:

【Aim】This study investigated the aerial insect species composition and the population dynamics of Spodoptera frugiperda in Nanning, aiming to identify the species composition and the dynamics of dominant pests, provide basic bases for pest monitoring and early warning, and formulate more effective strategies for the control of migratory pests.【Method】A searchlight trap aerial monitoring station was set up in the scientific research base of Guangxi Academy of Agricultural Sciences, Wuming, Nanning. Insects were collected from April to December 2022, followed by classification, identification, and statistical analysis.【Result】A total of 181 insect species belonging to 45 families of 10 orders were collected by the searchlight trap. Lepidoptera, Hemiptera, Orthoptera, and Coleoptera were the dominant taxa. The dominant species was Physopelta gutta. The abundant species included S. frugiperda and S. litura. The common species were Physopelta cincticollis, Helicoverpa armigera, Diaphania indica, Spoladea recurvalis, Gryllotalpa orientalis, and Heortia vitessoides. The population dynamics of S. frugiperda showed five distinct peaks, with the occurrence period concentrated from July to October, and the peak trap catch observed from mid-August to early September.【Conclusion】The aerial insects in Nanning are characterized by high species diversity and abundance. These research findings provide a foundation and data for pest forecasting, prediction and scientific control.

Abstract:

【Aim】This study aims to examine the function of LdecOR30 in the Colorado potato beetle, Leptinotarsa decemlineata. To do so, the odorant receptor gene OR30 from the antennae was cloned to determine the expression levels of LdecOR30 in different tissue samples of male and female adults, and investigate its electrophysiological responses to the main alcohols in various odor molecules.【Method】On the basis of the full-length transcriptome and next-generation transcriptome re-sequencing data of L. decemlineata, the coding sequence (CDS) of LdecOR30 was cloned by PCR. Quantitative real-time PCR (qPCR) was employed to analyze the expression profiles of LdecOR30 in the antennae, head (without antennae), thorax, abdomen, legs, and wings. The electrophysiological responses of LdecOR30 to 16 alcohols were examined via the Drosophila empty neuron system combined with single sensillum recording. A Y-tube olfactometer was employed to test the effects of specifically responsive compounds on the behavior of L. decemlineata.【Result】The full-length cDNA sequence of LdecOR30 was successfully cloned. Sequence analysis indicated that this odorant receptor contained six transmembrane domains. qPCR results showed significantly higher expression of LdecOR30 in the antennae of both male and female adults than in other tissue samples. Single sensillum recordings in the Drosophila empty neuron system indicated that LdecOR30 responded to five alcohols, with an increase of over 20 spikes per second. Y-tube olfactometer assays demonstrated that cis-3-hexen-1-ol had a significant attractive effect on female beetles, with an attraction rate of 80%, while 1-octen-3-ol exhibited significant repellency of 70% to both male and female adults.【Conclusion】The odorant receptor gene LdecOR30 is highly expressed in the antennae of L. decemlineata adults, regardless of sex, and responds to five different alcohols, including cis-3-hexen-1-ol. These findings suggest that LdecOR30 plays an important role in the recognition and localization of host plants by L. decemlineata.

Abstract:

【Aim】This study investigated the inhibitory effects of Callicarpa nudiflora leaf extract on the seed germination, stem cutting rooting, and potted plant growth of Mikania micrantha and analyzed the rhizosphere microbiome, aiming to reveal the potential ecological mechanisms of the allelopathic effects.【Method】This study investigated the allelopathic effects of 75% ethanol extract from C. nudiflora leaves on the seed germination, stem cutting rooting, and potted plant growth of M. micrantha and analyzed the rhizosphere microbiome to elucidate underlying mechanisms.【Result】(1) The 0.1% extract from January-harvested leaves (LY-H) exhibited the strongest inhibition on seed germination, reducing the germination rate, germination energy, and germination index by 77.1%, 76.2%, and 74.3%, respectively (p<0.01), compared with the control group (CK), with a synthetical allelopathic effect index (SE) of ?0.76. (2) The 0.1% extract from July-harvested leaves (XY-H) suppressed stem cutting rooting, decreasing the root number and length by 68.7% and 57.6%, respectively (p<0.05), with a SE of ?0.632. (3) In pot experiments, LY-H treatment reduced the total bolting length and stem weight of M. micrantha by 50.0% and 38.3%, respectively (p<0.05), showcasing persistent inhibitory effect. (4) The rhizosphere microbial analysis revealed that treated groups showed decreased abundance of nitrogen-fixing bacteria (e.g., Rhizobium) and nitrifying bacteria (e.g., Nitrospira) (p<0.01) and increased abundance of soil-remediating bacteria (e.g., Pseudomonas), suggesting that microbiome remodeling may indirectly enhance allelopathy by limiting nitrogen availability.【Conclusion】C. nudiflora leaf extract suppresses the growth of M. micrantha through dual pathways of allelochemical action and microbial regulation. The findings provide a novel eco-friendly strategy for invasive plant management.

Abstract:

【Aim】Global warming affects the geographical distribution patterns of invasive species. The Colorado potato beetle, Leptinotarsa decemlineata Say, is a quarantine pest causing substantial economic losses in global agricultural production. Studying its potential distribution dynamics under future climate change holds critical implications for the early monitoring, warning, and the development of control strategies for this pest.【Method】A parameter-optimized MaxEnt model was developed integrating 2 113 global distribution records and 8 key environmental variables to predict the global potential geographic distribution of L. decemlineata under the near-current (1970—2000) and future climate scenarios (SSP1-2.6, SSP2-4.5, and SSP5-8.5) across two periods (2021—2040 and 2041—2060).【Result】The mean temperature of coldest quarter (bio11) and precipitation of driest month (bio14) were identified as the dominant environmental variables shaping the potential distribution of L. decemlineata. Currently, highly suitable habitats are primarily concentrated in North America, Europe, and parts of Asia. Under SSP1-2.6, the potential distribution exhibi-ted a trend of initial increase followed by decrease, while under SSP2-4.5 and SSP5-8.5, the trend was initial decrease followed by increase, with the peak occurring during 2021—2040 under SSP5-8.5.【Conclusion】Environmental factors, primarily bio11 and bio14, collectively shape the boundaries of the potential geographic distribution of L. decemlineata. North America, Europe, and parts of Asia, South America, Oceania, and Africa consistently remain highly suitable habitats. Climate change is accelerating the expansion of this insect towards higher latitudes. The findings provide a scientific basis for formulating cross-border quarantine policies and early warning and control strategies against L. decemlineata.

Abstract:

【Aim】Ambrosia trifida, an invasive alien plant, exhibits strong ecological adaptability, causing severe damage to agriculture, forestry, animal husbandry and related industries in China, while posing significant threats to ecosystems and biodiversity. Studying the potential geographic distribution of A. trifida in Guizhou province is crucial for monitoring, early warning, and control of this plant.【Method】The information of 108 domestic occurrence records and 38 environmental and soil variables, as well as the MaxEnt model, ArcGIS software, and Pearson correlation analysis, were employed to predict the potential suitable areas of A. trifida in Guizhou under historical (1970—2000) and future climate scenarios (SSP1-26, SSP2-45, SSP3-70, and SSP5-85).【Result】The AUC value of the MaxEnt model constructed with 19 variables reached 0.945, indicating higher predictive reliability. The presence probability of A. trifida increased with increases in mean diurnal range (b2, 2.79-11.56℃), isothermality (b3, 15.38-24.16), precipitation of driest month (b14, 0-4.83 mm or greater than 16.54 mm), precipitation of coldest quarter (b19, 0-16.26 mm), precipitation seasonality (b15, coefficient of variation: 11.53-51.06 or 90.28-144.72), and precipitation of warmest quarter (b18, 0-83.71 mm or 219.99-418.74 mm). Under historical conditions, the total suitable area of A. trifida in China was 199 910 km²(20.82% of the national territory), with high, medium, and low suitable areas accounting for 0.61%, 5.84%, and 14.37%, respectively. In Guizhou, the medium suitable areas (15.49%, 25 800 km²) concentrated in central-eastern Guiyang City, central-southwestern Qiandongnan Prefecture, and parts bordering Bijie City and Zunyi City. The low suitable area was 71 900 km², accounting for 43.21%. No high suitableareas were identified. Over the four future scenarios and periods, the sum of low and medium suitable areas fluctuated between 48 400 km² and 86 800 km². Compared to the current situation, this represented a decline of 11.15% to 50.49%. Unsuitable areas will still dominate, and there will still be no high suitable areas.【Conclusion】Elevation (el), mean diurnal range (b2), isothermality (b3), precipitation of driest month (b14), precipitation of coldest quarter (b19), precipitation seasonality (b15), precipitation of warmest quarter (b18), and soil sulfate content (t_CaSO₄) were identified as critical factors influencing the distribution of A. trifida. In Guizhou, 58.71% of the area was suitable. Under four future scenarios, medium and low suitable areas showed initial expansion followed by contraction toward central and southwestern Guizhou. The contraction/expansion of medium suitable areas was concentrated in Zunyi Ccity, Tongren City, and border between Qiandongnan Prefecture and Qiannan Prefecture, while that of low suitable areas occurred in central-western regions (Anshun City, Liupanshui City, and Qianxinan Prefecture). This study provides critical insights for early monitoring, intervention, and control of A. trifida to mitigate its ecological and economic impacts in Guizhou.

Abstract:

【Aim】This study examines the distribution patterns and invasion risks of alien invasive plants after soil erosion control in Changting County, Fujian Province. It aimed to provide a scientific basis for the formulation of risk-based tiered monitoring strategies and targeted management measures.【Method】The line transect method was used for on-site investigations on the composition, habitat types, and invasion areas of introduced alien plant species. A risk assessment system for invasive alien plants in Changting County was constructed, and the risk levels were graded. The distribution characteristics of the invasive plants with the highest risk level were analyzed.【Result】A total of 50 alien invasive plant species were recorded, belonging to 35 genera of 20 families. Herbaceous species predominated, with 48 species accounting for 96% of the total. Asteraceae had the highest representation, with 16 species (32% of the total), followed by Amaranthaceae with 6 species (12% of the total). Approximately 90% of the invasive species originated from the Americas. The risk assessment results indicated that invasive alien plants in Changting County can be classified into five risk grades: extremely high risk (Grade Ⅰ, 6 species), high risk (Grade Ⅱ, 8 species), moderate risk (Grade Ⅲ, 16 species), low risk (Grade Ⅳ, 16 species), and extremely low risk (Grade Ⅴ, 4 species). In Changting County, invasive species were mainly distributed along roadsides, with the highest species richness observed in the southern townships. Extremely high-risk alien plants were concentrated in the central and northeastern townships, with Xinqiao and Sanzhou towns exhibiting the highest overall invasion risk.【Conclusion】The invasive plants in Changting County are mainly members of Asteraceae, herbaceous plants, and species originated from the Americas. A new invasive plant, Erigeron sumatrensis, was also discovered. It is suggested that the dominant species of Asteraceae should be controlled by using native plants with similar ecological niches, and special attention should be paid to the areas with high road density and the boundaries of towns.

Abstract:

【Aim】This study investigated the antibacterial mechanism of the extract from a biocontrol bacterium isolated from tobacco rhizosphere soil against Ralstonia solanacearum, the causal agent of tobacco bacterial wilt, aiming to provide a new candidate strain for the biocontrol of this disease.【Method】Antagonistic bacteria with significant inhibitory effects against R. solanacearum were isolated from the rhizosphere soil of healthy tobacco plants via the plate confrontation assay. The selected strain was identified through morphological, physiological, biochemical, and molecular biological analyses. Its disease control and plant growth-promoting efficacy were evaluated through greenhouse experiments, and its colonization in tobacco rhizosphere soil and tobacco plants was detected via an antibiotic marker method. Furthermore, a 96-well plate method was employed to determine the minimum inhibitory concentration (MIC) of the bacterial extract against R. solanacearum, and thus evaluating the effect of the strain on R. solanacearum.【Result】A biocontrol bacterial strain, designated FY3-17, which exhibited significant inhibitory activity against R. solanacearum, was isolated from tobacco rhizosphere soil and identified as Serratia marcescens. Greenhouse experiment results showed that the fermentation broth of FY3-17 provided the control efficacy of 73.98% against tobacco bacterial wilt and significantly promoted tobacco plant growth. Furthermore, this strain stably colonized both the tobacco rhizosphere soil and the tobacco plants. On day 42 post-inoculation, the maximum colonization density (2.0×10⁴ CFU·g^-1) was observed in rhizosphere soil, followed by roots (5.35×10³ CFU·g^-1), stems (8.90×10² CFU·g^-1), and leaves (4.57×10¹ CFU·g^-1). Additionally, the extract of FY3-17 significantly inhibited the growth of R. solanacearum, with an MIC of 40 μg·mL^-1, and it interfered with the biofilm formation and extracellular polysaccharide production.【Conclusion】The S. marcescens strain FY3-17 screened in this study demonstrates considerable potential for controlling tobacco bacterial wilt and promoting plant growth, indicating promising prospects for development and application.

Abstract:

【Aim】The fusion TEER-decreasing protein (fTDP) induces tobacco resistance to tobacco mosaic virus (TMV). To enhance the field efficacy and stability of fTDP, we optimized the combination ratios of agents and explored the induction mechanism. 【Method】Using Nicotiana tabacum var. Samsun NN and N. tabacum K326 as materials, we analyzed the number of necrotic spots, disease symptoms, and expression levels of the TMV coat protein gene (TMV-CP) in tobacco plants treated with different agents to identify the most effective antiviral agent. The optimal ratio of the selected agent, ningnanmycin, to fTDP was determined via the co-toxicity coefficient method. The disease resistance efficacy and resistance pathways of the fTDP/ningnanmycin combined agent were evaluated based on indicators such as plant growth status, defense enzymes, and defense genes. The field application efficacy of the combined agent was measured with Yunyan 87 as the material. 【Result】Ningnanmycin and fTDP delayed the appearance of mosaic symptoms of tobacco and significantly reduced the viral load. When the mass ratio of fTDP to ningnanmycin was 3 : 7, the combined agent exhibited a significant synergistic effect of TMV inactivation, with a co-toxicity coefficient of 152. When the mass ratio of fTDP to ningnanmycin was 1 : 9, the combined agent protected tobacco K326 from TMV infection, with a significant synergistic effect. In addition, the combined agent increased salicylic acid content, defense enzyme activity, and expression levels of multiple disease resistance-related protein genes in tobacco K326. Field trial results demonstrated that the combined agent at this ratio exhibited higher and more stable efficacy than the single agents, achieving the control efficacy of 77.8%. 【Conclusion】The fTDP/ningnanmycin combined agent enhances tobacco resistance to TMV by activating the salicylic acid signaling pathway. When the mass ratio of fTDP to ningnanmycin was 1 : 9, the combined agent outperformed single agents in both antiviral activity and cost reduction in both laboratory and field settings.

Abstract:

【Aim】This study aims to develop a rapid, sensitive, convenient, and visual loop-mediated isothermal amplification (LAMP) detection method for Albonectria rigidiuscula, providing technical support for the rapid detection and accurate management of this invasive pest.【Method】LAMP primers were designed based on the EF-1α and Tub sequences of A. rigidiuscula, and a set of effective primers was screened. The reaction temperature was optimized, and the specificity and sensitivity of the method were evaluated. Additionally, the host of A. rigidiuscula was detected.【Result】The visual LAMP detection method established in this study achieved the detection of A. rigidiuscula within 1 h. No amplification band was produced for the 19 other pathogenic strains tested, and only A. rigidiuscula exhibited amplification, which demonstrated the excellent specificity of the established method. The optimal detection temperature was 65 ℃, and the detection sensitivity reached 21.84×10^-4 ng·μL^-1. In practical applications, the method achieved an accuracy rate of 100%, and the test results could be intuitively interpreted.【Conclusion】The LAMP method developed in this study for the detection of A. rigidiuscula features a short reaction time, strong specificity, high sensitivity, simple operation, and visual detection results. It is suitable for port quarantine and field detection of A. rigidiuscula.