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Background Plant breeding for resistance to agricultural pests is an essential element in the development of integrated crop management systems; however, the molecular and genetic mechanisms underlying resistance are poorly understood. In this pilot study, a transcriptomic analysis of a resistant (R) vs. a susceptible (S) variety of alfalfa, with (+T) or without (−T) thrips (= 4 treatments) was conducted, ‘GN-1’ (China) was defined as the resistant cultivar, and ‘WL323’ (America) was defined as the susceptible cultivar. Results A total of 970 mRNAs were differentially expressed, of which 129 up- and 191 down-regulated genes were identified in the R + T/R-T plants, while 413 up- and 237 down-regulated genes were identified in the S + T/S-T plants. KEGG analysis mapped 33 and 80 differentially expressed genes to 11 and 14 substantially enriched pathways for GN-1 and WL323, respectively. Five shared pathways were linked to plant resistance traits, including beta-Alanine metabolism, fatty acid degradation, chloroalkane and chloroalkene degradation, flavonoid biosynthesis, and phenylalanine metabolism. Conclusions Results indicated both thrips resistant and susceptible alfalfa cultivars can regulate gene expression in the salicylic acid (SA) and flavonoid biosynthesis pathways to induce defensive genes and protein expression (e.g. polyphenol oxidase, protease inhibitor), which enhances plant defence capacity.

Background Locust migration is one of the main causes of locust plagues. While existing research has highlighted the adaptive migratory capabilities of locusts, the evolutionary patterns of their migration remain elusive. This study aims to explore these evolutionary patterns of locust migratory behavior at the genomic level. To achieve this, we conducted comparative genomics analysis using genomic data from 10 locust species with diverse migratory tendencies. Results We identified 1064 genes showing signatures of positive selection in five migratory locust species using a dN/dS model. The BUSTED-PH model revealed 116 genes associated with migratory phenotypes. Gene ontology enrichment analysis indicated that these genes were predominantly related to metabolism and mitochondria-related pathways through both methods. Additionally, the evolutionary rate (RER) analysis between migratory and non-migratory locusts revealed significant divergence in energy metabolism pathways. Notably, of the genes analyzed, the SETX gene consistently showed evidence of positive selection across all five migratory species. Conclusions The findings suggest that the evolution of migratory behavior is associated with increased selective pressure on metabolism and mitochondria-related pathways. Hundreds of genes undergo selective changes during repetitive transitions to migratory behavior. These findings enhance our understanding of the genetic and phenotypic relationships underlying different locust migratory behaviors, providing important data for understanding the biological mechanisms behind locust outbreaks.

Outbreaks of locust plagues are becoming increasingly frequent against the backdrop of climate change. Locust outbreaks in the Caucasus and Central Asia, especially in Kazakhstan, pose continuous threats to neighboring countries, including China, Kyrgyzstan, and more. However, locust outbreak forecasts and migration movement are yet to be studied in this area. In our study, we collected water level data in major lakes and water bodies, as well as annual average precipitation in the past 15 years in Kazakhstan, to analyze their contributions to locust outbreaks. Multiple linear regression analysis revealed a significant negative correlation between overall lake water level and the following year’s locust outbreak area in Kazakhstan. Considering that the overall lake water levels in 2023 and 2024 reached a quite low level historically, we predicted heavy locust outbreaks in 2025. Furthermore, through wind field analysis and wind-born trajectory modeling, we identified two migration routes of locusts from Kazakhstan into Xinjiang, China, riding the northwest wind, with lakes near the Sino-Kazakhstan border as the main sources. Overall, our study identified high locust outbreak challenges in Kazakhstan in recent years and determined two wind-supported migration routes of locusts invading China, which are significant for guiding monitoring and prevention efforts in the Sino-Kazakhstan border area.

Plant-derived volatile organic compounds (VOCs) are widely used as insect attractants for population monitoring, offering an efficient and eco-friendly approach to pest management. Since thrips are the dominant pest species in alfalfa (Medicago sativa) crops, alfalfa volatiles produced in the presence of Odontothrips loti and compounds with attractive potential to both O. loti and Frankliniella occidentalis were investigated. Using gas chromatography–mass spectrometry (GC-MS), 96 VOCs were identified from seven alfalfa cultivars with varying levels of thrips resistance with and without damage by O. loti. Eleven volatiles were selected for Y-tube olfactometer assays. The semiochemical p-Menth-8-en-2-one, which was suppressed in alfalfa subject O. loti damage, significantly attracted both O. loti and F. occidentalis in Y-olfactometer bioassays; the response rates were 2.05~3.07 times compared to control (p < 0.05). Further experiments confirmed p-Menth-8-en-2-one, dispensed through PE (Polyethylene) vials, was the most effective lure material with the concentrations of 10 ng/μL. This study demonstrated that the alfalfa-derived volatile p-Menth-8-en-2-one, shows significant attraction to thrips, which can be utilized for monitoring and management of odontothrips loti and frankliniella occidentalis.

Metarhizium anisopliae, an entomopathogenic fungus, can produce four extracellular proteases, subtilisin (Pr1), trypsin (Pr2), metalloproteases (Pr3), and cysteine proteases (Pr4), which are important for pathogenicity of M. anisopliae in target hosts. In order to understand their function in M. anisopliae pathogenicity, third-instar nymphs of Locusta migratoria were fed with a diet containing either conidia of M. anisopliae strain IPPM202 or in combination with one of the four inhibitors (TPCK: tosyl-phenylalanine chloromethyl-ketone, inhibitor of Pr1; EDTA: ethylenediaminetetraacetic acid, inhibitor of Pr3; APMSF: 4-amidinophenyl methanesulfonyl fluoride, inhibitor of Pr2; CI1: cathepsin inhibitor 1, inhibitor of Pr4). The effects on mortality, midgut integrity, and the gut enzymes peroxidase (POD), catalase (CAT), superoxide dismutase (SOD), and phenol oxidase (PO) were examined. The results indicated that exposure to IPPM202/TPCK and IPPM202/CI1 caused decreased mortality to L. migratoria with no loss of midgut epithelial cellular integrity. On the other hand, exposure to IPPM202/APMSF or IPPM202/EDTA mixtures resulted in higher mortality similar to PPM202, with severely damaged epithelial gut cells with fragmented microvilli, broken endoplasmic reticulum, and disrupted nucleus membrane. The activity of the protective enzymes POD, SOD, CAT, and PO all increased significantly when L. migratoria was treated with IPPM202 only, but decreased when any one of the inhibitors was added. We further concluded that TPCK, a subtilisin (Pr1) inhibitor, and CI1, a cysteine protease (Pr4) inhibitor, played important roles in the pathogenicity of the M. anisopliae strain IPPM202. Conversely, trypsin (Pr2) and metalloproteases (Pr3) did not have a role in the given process. We further concluded that trypsin (Pr2) and metalloproteases (Pr3) do not contribute to the fungal infection process, while the subtilisin (Pr1) inhibitor TPCK and cysteine protease (Pr4) inhibitor CI1 play critical roles in the pathogenicity of Metarhizium anisopliae strain IPPM202, thus providing a foundation for targeted biocontrol strategies.

Plant-derived volatile organic compounds (VOCs) are widely used as insect attractants for population monitoring, offering an efficient and eco-friendly approach to pest management. Since thrips are the dominant pest species in alfalfa fields, this study aimed to identify a suitable attractant trap design that could be employed to monitor Odontothrips loti and Frankliniella occidentalis. The field experiment showed that p-Menth-8-en-2-one, dispensed through PE (Polyethylene) vials positioned at the top of the alfalfa canopy, attracted the most thrips, with the optimal concentrations of 1 µg/µL for O. loti and 50 µg/µL for F. occidentalis, respectively. When both species occur in alfalfa, PVC pipes dispensing p-Menth-8-en-2-one at a concentration of 1 µg/µL provide an effective attractant for both species, offering an indication of presence and relative abundance. Understanding the incidence and abundance of both species in the field provides growers an opportunity to target treatments to protect crops before significant damage occurs, reduce insecticide overuse, and support integrated pest management strategies for these two high-impact pests.

Medicago sativa L. (alfalfa, syn. lucerne) is an important forage crop for livestock, which is subject to attack from a range of insect pests and susceptible to diseases that can reduce production and persistence. This review considers the main insect pests affecting M. sativa in China and New Zealand as well as the wider plant resistance mechanisms and multitrophic interaction that occur between plants, insect pests, entomopathogens, endophytes, the environment, and climate change. This is with a view to identifying new research opportunities applicable to M. sativa that can be applied to improving production and persistence of this important agricultural crop. These opportunities include identification and activity of entomopathogens/endophytes (e.g., Bacillus and Pseudomonas spp., Metarhizium spp.) and plant growth enhancers ( Trichoderma ), as well as multitrophic plant-insect-microbial interactions.

The locust Oedaleus decorus undergoes massive outbreaks and engages in round-trip migratory flights across northern China and Mongolia. However, its specific genetic structure remains poorly understood. In this study, we sequenced the complete mitochondrial genomes of 163 O. decorus individuals from 16 locations in northern China using high-throughput sequencing data and analyzed its population structure. The results showed that these mitochondrial genomes are 15,142 to 15,914 bp in sizes, with size variation attributed to A + T-rich regions in intergenic spacers. All 13 protein-coding genes exhibited conserved lengths across samples. The overall genetic differentiation between populations was small (Fst = 0.00843), with high gene flow (Nm = 29.40). Both genetic differentiation and DAPC analyses revealed significant genetic differentiation in the New Barag Left Banner (NBL) population compared to the Zhengxiangbai Banner (ZB), Taibus Banner (TP), Xianghuang Banner (XH), and Zhenglan Banner (ZL) populations. The phylogenetic tree and haplotype network suggest Hap_20 is presumably a relatively ancestral haplotype and all haplotypes were divided into two clades, and no population formed a distinct independent clade. Our findings indicate that the O. decorus population in North China exhibits mitochondrial subtype differentiation. The lack of difference in genetic structure across different regions in North China is consistent with a high level of migratory activity by O. decorus in the region.

FK506 binding proteins (FKBPs) are a highly-conserved group of proteins known to bind to FK506, an immunosuppressive drug. They play different physiological roles, including transcription regulation, protein folding, signal transduction and immunosuppression. A number of FKBP genes have been identified in eukaryotes; however, very little information about these genes has been reported in Locusta migratoria . Here, we identified and characterized 10 FKBP genes from L. migratoria . Phylogenetic analysis and comparison of domain architectures indicated that the LmFKBP family can be divided into two subfamilies and five subclasses. Developmental and tissue expression pattern analysis revealed that all LmFKBPs transcripts, including LmFKBP46 , LmFKBP12 , LmFKBP47 , LmFKBP79 , LmFKBP16 , LmFKBP24 , LmFKBP44b , LmFKBP53 , were periodically expressed during different developmental stages and mainly expressed in the fat body, hemolymph, testis, and ovary. In brief, our work depicts a outline but panoramic picture of LmFKBP family in L. migratoria , and provides a solid foundation to further investigate the molecular functions of LmFKBPs .

We studied the role of plant primary and secondary metabolites in mediating plant-insect interactions by conducting a no-choice single-plant species field experiment to compare the suitability, enzyme activities, and gene expression of Oedaleus asiaticus grasshoppers feeding on four host and non-host plants with different chemical traits. O. asiaticus growth showed a positive relationship to food nutrition content and a negative relationship to secondary compounds content. Grasshopper amylase, chymotrypsin, and lipase activities were positively related to food starch, crude protein, and lipid content, respectively. Activity of cytochrome P450s, glutathione-S-transferase, and carboxylesterase were positively related to levels of secondary plant compounds. Gene expression of UDP-glucuronosyltransferase 2C1, cytochrome P450 6K1 were also positively related to secondary compounds content in the diet. Grasshoppers feeding on Artemisia frigida , a species with low nutrient content and a high level of secondary compounds, had reduced growth and digestive enzyme activity. They also had higher detoxification enzyme activity and gene expression compared to grasshoppers feeding on the grasses Cleistogenes squarrosa , Leymus chinensis , or Stipa krylovii . These results illustrated Oedaleus asiaticus adaptive responses to diet stress resulting from toxic chemicals, and support the hypothesis that nutritious food benefits insect growth, but plant secondary compounds are detrimental for insect growth.