Search Results (207)

Defensins are a class of small cysteine-rich cationic antimicrobial peptides (AMPs) that play vital roles in immune-regulating insect–microbe interaction, offering great potential for developing pest control approaches using RNA interference (RNAi) and insect pathogens. However, the biocontrol potential of defensins from the destructive rice pest Nilaparvata lugens (brown planthopper, BPH) remains largely unexplored. Here, we identified and functionally characterized a defensin-encoding gene NldefB in BPH. The open reading frame (ORF) of NldefB is 315 bp in length, encoding 104 amino acids with a conserved Knot1 domain. The qRT-PCR results showed that the transcription level of NldefB went upward with the increasing developmental stages, with the highest expressions in the female adults and their fat body. The expression of NldefB was continuously induced by bacterial pathogens but exhibited a pattern of initial increase followed by a decrease when challenged by a fungal pathogen Metarhizium anisopliae. RNAi-mediated silencing of NldefB significantly decreased the host survival rate, egg production and hatchability, as well as the capability to resist fungal infection. Additionally, NldefB suppression resulted in a significant increase in microbial loads. Our findings underscored that NldefB plays essential roles in regulating host development, pathogen defense, and microbial maintenance, providing a potential target for RNAi- and microbe-mediated BPH biocontrol. Full article

The brown planthopper, Nilaparvata lugens, a major rice pest, harbors yeast-like symbionts (YLSs) that form mutualistic relationships with the host, significantly influencing its development and reproduction. As proteasome subunits play major roles in the assembly and functional maintenance of the proteasome, but their regulation on the YLSs in N. lugens are unclear. In this study, we analyzed the spatiotemporal and temporal expression patterns of five N. lugens proteasome subunits (NlPSMA2, NlPSMB5, NlPSMC4, NlPSMD10, NlPSMD13), and further verified their functions on the transovarial transmission of YLSs, in addition to the reproduction of N. lugens, based on RNA interference (RNAi). The results showed that NlPSMA2, NlPSMB5, NlPSMC4, NlPSMD10, and NlPSMD13 were highly expressed in ovarian follicular cells of N. lugens upon sexual maturation. After suppressing the expression of these genes by RNAi, N. lugens exhibited a shortened lifespan, abnormal pear-shaped follicles, and impaired oviposition capacity, but the number of YLSs in the whole body and the oocyte of N. lugens were significantly increased. These results indicate that the proteasome subunits play crucial roles in the reproduction of N. lugens and the transovarial transmission of its YLSs. Full article

The fragrant and soft rice variety Diantun 502 has been a major cultivar for high-quality rice production in Yunnan Province since its approval in 1993. Over 30 years of widespread cultivation, several issues affecting this variety—including high susceptibility to rice blast, reduced yield, and declining quality—have been noted. To address these limitations, this study aimed to improve and upgrade Diantun 502. During the breeding process, parent lines with soft rice traits were selected, and molecular marker-assisted selection was employed using the soft rice gene Wx^hp and the fragrance gene badh2. Priority was given to grain quality while also considering agronomic performance. Natural induction tests were conducted in rice blast-prone regions. After 9 years of selection and evaluation, the new variety—Diangu 1839—was successfully developed. Comparative analysis of agronomic and economic traits, as well as gene loci between Diantun 502 and the improved variety Diangu 1839, revealed that the observed trait changes in Diangu 1839 corresponded with the presence of the targeted gene loci. This study involved a comparative analysis of agronomic and economic traits as well as key gene loci between Diantun 502 and the improved variety Diangu 1839. The results showed that, compared to Diantun 502, Diangu 1839 achieved a 14.1% increase in yield and a significant 25.6% reduction in chalky grain rate. Importantly, the retention of badh2 and Wx^hp genes ensured the preservation of excellent eating quality, while rice blast resistance was enhanced. Although Diangu 1839 demonstrated significant improvements in yield, rice quality, and disease resistance, its resistance to brown planthopper remains limited due to the lack of corresponding resistance genes. The technical system and breeding experience established in this study provide important technical references for the genetic improvement of high-quality, fragrant, and soft rice varieties. Full article

Rice planthoppers are the most destructive pests of rice production and the vectors of rice viruses. Fenmezoditiaz as a novel mesoionic insecticide is used for rice planthopper management by targeting the insect’s neural nicotinic acetylcholine receptor. This study aimed to evaluate the effects of fenmezoditiaz on the acquisition, propagation, and transmission of southern rice black-streaked dwarf virus (SRBSDV) by the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacida). The results revealed that sublethal concentrations of fenmezoditiaz significantly impaired SRBSDV acquisition and viral replication in S. furcifera. Fenmezoditiaz-treated viruliferous S. furcifera exhibited a lower transmission efficiency of SRBSDV to un-infected rice seedlings. Electrical penetration graph (EPG) recordings revealed prolonged non-probing (NP), salivary secretion (N2/N3), and xylem feeding (N5) durations, alongside shortened phloem contact behavior (N4a/N4b), of fenmezoditiaz-treated individuals, indicating disrupted feeding behaviors, which are critical for reducing viral infection. By reducing viral titers and interfering with phloem ingestion, fenmezoditiaz significantly suppresses SRBSDV transmission. These findings revealed fenmezoditiaz’s dual role in pest control and viral transmission blockage, providing a foundation for incorporation into integrated management of vector-borne plant viruses. Full article

The brown planthopper, Nilaparvata lugens (Stål, 1854), is the most devastating pest of rice (Oryza sativa L.). Although insecticides are used to control this pest, host plant resistance is a more effective and economic solution. Therefore, identification of N. lugens-resistant genes and elucidation of their underlying resistance mechanisms are critical for developing elite rice cultivars with enhanced and durable resistance. Research has shown that in the long-term evolutionary arms race, rice has developed complex defense systems against N. lugens, while N. lugens has developed diverse and sophisticated strategies to overcome the plant’s defenses. This review emphasizes recent advances in the molecular interactions between rice and the N. lugens, particularly focusing on the resistance mechanisms of 17 cloned major N. lugens resistance genes, which have significantly improved our understanding of the molecular basis of rice–N. lugens interactions. We also highlight the roles of several N. lugens salivary components in activating or suppressing rice defense responses. These insights provide a foundation for developing sustainable and effective strategies to manage this devastating pest of rice. Full article

Insects and their bacterial endosymbionts form intricate ecological relationships, yet their role in host–pathogen interactions are not fully elucidated. The small brown planthopper (Laodelphax striatellus), a polyphagous pest of cereal crops, acts as a key vector for rice stripe virus (RSV), a significant threat to rice production. This study aimed to compare the endosymbiont community structures of nonviruliferous and RSV-viruliferous L. striatellus populations using 16S rRNA gene sequencing with high-throughput sequencing technology. Wolbachia was highly dominant in both groups; however, the prevalence of other endosymbionts, specifically Rickettsia and Burkholderia, differed markedly depending on RSV infection. Comprehensive microbial diversity and composition analyses revealed distinct community structures between nonviruliferous and RSV-viruliferous populations, highlighting potential interactions and implications for vector competence and virus transmission dynamics. These findings contribute to understanding virus-insect-endosymbiont dynamics and could inform strategies to mitigate viral spread by targeting symbiotic bacteria. Full article

The brown planthopper (BPH), Nilaparvata lugens, is the most destructive insect pest of rice. BPH infestations severely threaten rice yield worldwide. The gustatory receptor NlGr23 plays a critical role in mediating the repulsive reaction to oxalic acid of the BPH. We integrated transcriptomic and proteomic analyses to determine the metabolic and behavioral consequences of NlGr23 silencing. The RNAi-mediated knockdown of NlGr23 increased body weight and honeydew production, indicating enhanced feeding activity. The results of multiomics profiling revealed disrupted lipid homeostasis, identifying 187 differentially expressed genes and 150 differentially expressed proteins. These genes were enriched in pathways including glycerophospholipid metabolism, fatty acid biosynthesis, and AMPK signaling. The results of biochemical assays showed that NlGr23 silencing elevated triacylglycerol levels by 68.83%, and reduced glycerol and free fatty acid levels, suggesting impaired lipolysis. The NlGr23 loss-of-function mutation mechanistically activates the AMPK pathway, suppresses lipid breakdown, and promotes energy storage. This study established NlGr23 as a key regulator linking chemosensation to metabolic reprogramming, providing new insights into gustatory receptor-mediated energy homeostasis in the BPH. Full article

Rice (Oryza sativa L.) has long been threatened by the brown planthopper (BPH, Nilaparvata lugens) and white-backed planthopper (WBPH, Sogatella furcifera). It is difficult to detect and count rice planthoppers from RGB images, and there are a limited number of publicly available datasets for agricultural pests. This study publishes a publicly available planthopper dataset, explores the potential of YOLOv8-p2 and proposes an efficient improvement strategy, designated SwinT YOLOv8-p2, for detecting and counting BPH and WBPH from RGB images. The Swin Transformer was incorporated into the YOLOv8-p2 in the strategy. Additionally, the Spatial and Channel Reconstruction Convolution (SCConv) was applied, replacing Convolution (Conv) in the C2f module of YOLOv8. The dataset contains diverse pest small targets, and it is easily available to the public. YOLOv8-p2 can accurately detect different pests, with mAP50, mAP50:95, F1-score, Recall, Precision and FPS up to 0.847, 0.835, 0.899, 0.985, 0.826 and 16.69, respectively. The performance of rice planthopper detection was significantly improved by SwinT YOLOv8-p2, with increases in mAP50 and mAP50:95 ranging from 1.9% to 61.8%. Furthermore, the correlation relationship between the manually counted and detected insects was strong for SwinT YOLOv8-p2, with an R² above 0.85, and RMSE and MAE below 0.64 and 0.11. Our results suggest that SwinT YOLOv8-p2 can efficiently detect and count rice planthoppers. Full article

Rice, a vital crop, faces significant threats from the brown planthopper (BPH), which impacts plant growth and yield. Pyramiding the BPH resistance genes BPH14 and BPH15 provides rice crops with reliable and lasting protection against BPH. Nonetheless, current research lacks clarity on the molecular processes responsible for BPH14/BPH15-mediated resistance to BPH. In this study, utilizing high-throughput metabolomics and integrating transcriptomic data, we investigated the metabolic adaptations of the BPH14/BPH15 pyramiding line (B1415) and its recurrent parent (RP) during early and late infestation stages. The analysis identified 1007 metabolites, mainly consisting of lipids and lipid-like molecules, together with phenylpropanoid and polyketide classes. Differentially accumulated metabolites (DAMs) displayed different patterns in B1415 and RP, particularly in flavonoid and phenylpropanoid biosynthesis pathways, which were more pronounced in the resistant B1415. Furthermore, ferulic acid (FA) was found to negatively regulate BPH resistance. These findings elucidate critical metabolic pathways involved in rice defense mechanisms and underscore the potential of B1415’s enhanced metabolic responses in conferring durable resistance against BPH. Full article

Spiders play a crucial role as predators in terrestrial ecosystems, particularly in controlling insect populations. Tetragnatha keyserlingi Simon (Araneae: Tetragnathidae) is a dominant species in rice field ecosystems, where it builds webs amidst rice clusters to capture prey. Despite its known predation on major rice pests like rice planthoppers, comprehensive field reports on its prey composition are scarce. Herein, we performed a field investigation to explore the population dynamic relationships between T. keyserlingi and major rice pests. Additionally, we employed DNA metabarcoding to analyze the prey spectrum of this spider from both the spider’s opisthosoma and its web. The results showed that the population dynamics of T. keyserlingi and Nilaparvata lugens (Stål) displayed synchrony. Dietary DNA metabarcoding analysis revealed that, compared with the opisthosoma, DNA extracted from spider webs exhibited a higher abundance of prey reads and yielded a higher diversity of identified prey species. Phytophagous pests were the dominant prey group identified in both sample types. In web samples, the most abundant prey reads were from Chironomidae, followed by Delphacidae, Ceratopogonidae, Aleyrodidae, Muscidae, Coenagrionidae, and other prey families. Notably, Delphacidae constituted the predominant prey reads identified from the spider’s opisthosoma, and the corresponding positive rate for Delphacidae was 86.7%. These results indicate that the web of T. keyserlingi can capture a diverse range of prey in rice fields. Among the prey captured by the spider web, rice planthoppers appear to be a primary dietary component of T. keyserlingi, emphasizing its potential as a biocontrol agent for rice planthoppers in integrated pest management strategies. Leveraging spider web DNA metabarcoding enhances our understanding of T. keyserlingi’s prey capture ability, as the residual prey DNA in webs provides critical insights into the foraging dynamics and ecological interactions of web-building spiders. Full article

Recently, rice yield has been severely affected by both brown planthopper (BPH, Nilaparvata lugens) infestation and high-temperature stress. Numerous previous studies have identified genes conferring resistance to BPH and high-temperature tolerance in rice, respectively. However, it remains unclear how rice synergistically responds to these two stress factors. In the present study, we found that pre-treatment with high temperature can enhance rice seeding resistance to BPH, while BPH feeding did not alter the high-temperature tolerance of rice. This result can be elucidated by the subsequent transcriptome analysis. Differentially expressed genes (DEGs) following high-temperature treatment were enriched in metabolic processes and phenylpropanoid biosynthesis pathways, thereby enhancing rice resistance to BPH. Further weighted gene co-expression network analysis (WGCNA) indicated that genes in the magenta and black modules were predominantly associated with the protein folding and transmembrane transport biological processes. And several candidate genes, including Loc_Os01g02170 and Loc_Os01g59870, were identified that may play crucial roles in simultaneously regulating rice resistance to BPH and high-temperature stress. This research will provide new gene resources for cultivating rice with compound traits and provide ideas for the mechanism analysis of rice response to multiple stresses. Full article

The crucial roles of the lipase-like protein enhanced disease susceptibility 1 (EDS1) and phytoalexin deficient 4 (PAD4) in disease resistance in Arabidopsis have been identified. However, their function in rice (Oryza sativa L.) resistance to brown planthopper (BPH, Nilaparvata lugens Stål), the most notorious pest of rice, remains unknown. In this study, the transcript levels of OsEDS1 and OsPAD4 were rapidly altered by BPH infestation. Mutation in either OsPAD4 or OsEDS1 resulted in increased rice susceptibility to BPH, which was associated with increased honeydew excretion and an increased host preference of BPH. Furthermore, mutation in either OsPAD4 or OsEDS1 led to decreased basal levels of salicylic acid (SA) and jasmonic acid (JA) in the absence of BPH, along with the depressed expression of the defense-responsive genes OsPAL, OsICS1, OsPR1a, OsLOX1, OsAOS1 and OsJAZ11 involved in SA and JA biosynthesis and signaling. The BPH infestation-mediated elevation of SA levels and the expression of SA biosynthesis and signaling genes was dampened in eds1 and pad4 plants, whereas BPH infestation-mediated depressions of JA levels and the expression of JA biosynthesis and signaling genes were reversed in eds1 and pad4 plants. Taken together, our findings indicated that both OsPAD4 and OsEDS1 positively regulate rice resistance to BPH. Full article

The brown planthopper Nilaparvata lugens, a major rice pest, threatens global food security through rapid reproduction. This study investigates the role of the tramtrack (ttk) gene in male reproductive development and spermatogenesis using RNA interference (RNAi). Gene expression analysis revealed higher ttk levels in testes. RNAi-mediated knockdown of ttk in fourth-instar male nymphs reduced its expression by up to 80%, leading to severely impaired gonad development. Testes, vas deferens, and accessory glands in treated males exhibited 8–89% volume reductions compared to controls, accompanied by a 51–69% decline in sperm count and 60–85% reduction in sperm motility. Consequently, eggs fertilized by treated males showed a 73% decrease in hatching rates, with arrested embryonic development. These findings demonstrate ttk’s critical role in spermatogenesis and gonad maturation in N. lugens, highlighting its potential as an RNAi target for sustainable pest control strategies. Full article

The brown planthopper (BPH) is one of the major rice pests causing significant damage to rice production worldwide, due to its high reproductive capacity and strong migratory ability. A series of BPH-resistant rice varieties have been developed, but the durability of effective resistance is constrained by the evolution of BPH virulence, requiring in-depth insights into resistance mechanisms. In this paper, we used strand-specific lncRNA-seq to characterize the lncRNA regulatory mechanisms on rice response to BPH infestation. Overall, 4321 lncRNAs were identified, 60 of which were significantly upregulated in response to BPH infestation, specifically differing between BPH populations with variable virulence. Differential expression analysis and qRT-PCR validation showed that these lncRNAs are involved in the regulation of several defense pathways, including jasmonic acid signaling and flavonoid biosynthesis, with their distinct roles in resistant and susceptible rice varieties. Notably, lncRNAs like LNC_002533 were found to be negatively correlated with flavonoid biosynthesis, suggesting a potential role in modulating rice defense responses. In contrast, LNC_001986 and LNC_000397 were positively correlated with genes involved in glutathione metabolism, which may be associated with enhanced resistance. These findings highlight the critical regulatory functions of lncRNAs in rice-BPH interactions and provide a molecular framework for improving rice resistance through targeted genetic engineering. This study significantly contributes to functional genomics by elucidating lncRNA-mediated regulatory mechanisms and offers promising avenues for developing durable pest-resistant rice varieties. Full article

The predatory function and numerical responses of natural enemy insects are critical for evaluating their biological control potential, particularly in understanding pest suppression mechanisms and ecological adaptability. Here, we examined the predation capacity of Tytthus chinensis Stål (Hemiptera: Miridae) on Sogatella furcifera eggs under laboratory conditions (24 ± 1 °C, 12:12 h light:dark photoperiod, 75% humidity). Functional response experiments were conducted at different prey densities (3, 4, 10, 20, and 30 eggs/day), and life table parameters were established to evaluate the effects of prey density on the development, reproduction, and population dynamics of T. chinensis. The daily average predation of nymphs significantly increased with age, and their functional responses fitted the Holling Type II response. In the adult stage, the daily average predation of females was significantly higher than that of males, and males had a higher a/T_h ratio, which reflected sex-specific predation strategies. Prey density significantly influenced survival, reproduction, and population dynamics. The minimum prey density required for population stability was 4 eggs/day, and survival and reproduction rates markedly increased at 10 eggs/day. At 30 eggs/day, females reproduced earlier, and the lifespan of males was shortened. These findings confirm the strong pest control ability of T. chinensis and highlight the critical role of S. furcifera egg density in regulating the population dynamics of T. chinensis. Full article