Brown Planthopper Research Articles

The Jinggangmycin-induced Mthl2 gene regulates the development and stress resistance in Nilaparvata lugens Stål (Hemiptera: Delphacidae)

Methuselah (Mth) belongs to the GPCR family B, which regulates various biological processes and stress responses. The previous transcriptome data showed jinggangmycin (JGM)-induced Mthl2 expression. However, its detailed functional role remained unclear in brown planthopper, Nilaparvata lugens Stål. In adult N. lugens, the Mthl2 gene showed dominant expressions, notably in ovaries and fat body tissues. The 3rd instar nymphs treated with JGM increased starvation, oxidative stress, and high temperature (34 °C) tolerance of the adults. On the contrary, under dsMthl2 treatment, completely opposite phenotypes were observed. The lipid synthesis genes (DGAT1and PNPLA3) of both females and males treated with JGM in the nymphal stage were observed with high expressions, while the lipolysis of the Lipase 3 gene was observed with low expressions. The JGM increased triglyceride (TG) content, fat body droplet size, and the number of fat body droplets. The same treatment also increased the Glutathione S-transferase (GST), catalase (CAT), and superoxide dismutase (SOD) activities. An increase in the heat shock protein (HSP70 and HSP90) expression levels was also observed under JGM treatment but not dsMthl2. The current study demonstrated the influential role of the Mthl genes, particularly the Mthl2 gene, in modulating the growth and development and stress-responsiveness in N. lugens. Thus, providing a platform for future applied research programs controlling N. lugens population in rice fields.

Characterization of the complete genome of oat sterile dwarf virus: a fijivirus occurring in the temperate climate zone of Europe.

Oat sterile dwarf virus (OSDV) is a fijivirus whose genome segments 7 to 10 were sequenced earlier. In the current study, the complete genome was sequenced. To confirm the genome ends, rapid amplification and sequencing of cDNA ends were performed. The complete OSDV genome consists of 10 double-stranded RNA (dsRNA) segments with a total size of 28,686 bp. The sense strand sequence of all segments has the terminal consensus sequence motif 5'-AACGA(5-7)… U(6-8)(A/U)GUC-3', in which the length of the stretches of A and U varies, being slightly shorter for segments 1-4 and longer for segments 5-10. The 3' end of segment 3 is …UGUC, not AGUC as in the other segments. Segments 5, 7, and 10 contain two small ORFs, while each of the other segments contains one long ORF. ORF7-2 and ORF9 are slightly longer than annotated before. Phylogenetic analysis based on amino acid sequences of the RNA-directed RNA polymerase (RdRP) placed OSDV between the plant fijiviruses and Nilaparvata lugens reovirus (NLRV), an insect fijivirus that does not replicate in plants. OSDV RdRP shares 48-49% sequence identity with other plant-infecting fijivirus RdRPs and 30% identity with that of NLRV. OSDV has earlier been reported in several Northern and Central European countries. The sequencing of the complete genome serves as a reference for identifying all segments in future high-throughput sequencing datasets, enabling the investigation of the molecular epidemiology and evolution of OSDV.

Ecological engineering in low land rice for brown plant hopper, Nilaparvata lugens (Stål) management.

Rice field bunds and edges can act as near crop habitats, available for planting flowering plants to attract and conserve the natural enemies. We evaluated the effect of ecological engineering on the incidence of Brown Planthopper (BPH), Nilaparvata lugens (Stål)(Hemiptera; Delphacidae) and the abundance of its predators in the rice variety Pusa Basmati-1121. Plots included the oilseed crops viz. sesamum, sunflower and soybean, with plantings of flowering crops marigold, balsam and gaillardia as bund flora around the edges of rice plots. Ecologically engineered plots contained both crops+flowers and resulted in a significantly reduced BPH population per hill in rice plots for 2019 (6.3) and 2020 (9.4) compared to the control plots (9.8 and 14.4). Ecologically engineered plots also witnessed the delayed appearance of BPH during each growing season. Peak BPH populations are lower in the ecologically engineered plots than in the control grounds. Furthermore, the activity of natural enemies, viz., spiders, mirid bugs and rove beetles was the highest in rice fields planted with oilseed crops like sesamum, sunflower and soybean. Olfactory response studies showed that the attraction response of spiders toward sesamum and balsam leaves was more significant than in other crop plants. Rice yield was enhanced in plots planted with crops+flowers during both seasons compared to control plots. Planting of oilseed crops plants such as sesamum, sunflower and soybean with flowering crops such as marigold, balsam and gaillardia as bund flora on the bunds around the main rice field enhanced the natural enemy activity, suppressed the planthopper population, and increased yields. Based on the results, we recommend including ecological engineering techniques as one of the management components in the Integrated Pest Management programme for rice crops.

Knocking Out OsRLK7-1 Impairs Rice Growth and Development but Enhances Its Resistance to Planthoppers.

Leucine-rich repeat receptor-like kinases (LRR-RLKs) are an important subfamily of receptor-like kinases (RLKs) in plants that play key roles in sensing different biotic and abiotic stress. However, the role of LRR-RLKs in herbivore-induced plant defense remains largely elusive. Here, we found that the expression of a rice gene, OsRLK7-1, was induced by mechanical wounding, but was slightly suppressed by the infestation of gravid females of brown planthopper (BPH, Nilaparvata lugens) or white-backed planthopper (WBPH, Sogatella furcifera). Through targeted disruption of OsRLK7-1 (resulting in the ko-rlk lines), we observed an augmentation in transcript levels of BPH-induced OsMPK3, OsWRKY30, OsWRKY33, and OsWRKY45, alongside heightened levels of planthopper-induced jasmonic acid, JA-isoleucine, and abscisic acid in plant tissues. These dynamic changes further facilitated the biosynthesis of multiple phenolamides within the rice plants, culminating in an enhanced resistance to planthopper infestations under both lab and field conditions. In addition, knocking out OsRLK7-1 impaired plant growth and reproduction. These results suggest that OsRLK7-1 plays an important role in regulating rice growth, development, and rice-planthopper interactions.

Landscape structure influences natural pest suppression in a rice agroecosystem

Agricultural landscapes are constantly changing as farmers adopt new production practices and respond to changing environmental conditions. Some of these changes alter landscape structure with impacts on natural pest control, pesticide use, and conservation of biodiversity. In rice agroecosystems the effect of landscape structure on natural enemies and pest suppression is often poorly understood. Here we investigate the effect of landscape composition and configuration on a key pest of rice, the brown planthopper (Nilaparvata lugens). Using N. lugens as sentinel prey coupled with predator exclusions, we investigated landscape effects on herbivore suppression and rice grain yield at multiple spatial scales in two regions of Bangladesh. Ladybird beetles and spiders were the most abundant natural enemies of N. lugens with landscape effects observed at all scales on ladybird beetles. Specifically, ladybird beetles were positively influenced by road edges, and fallow land, while spiders were strongly influenced only by rice phenology. Predator exclusion cages showed that N. lugens abundance significantly increased in caged plots, reducing rice gain yield. We also used an estimated biocontrol service index that showed a significant positive relationship with landscape diversity and a significant negative impact on pest density and yield loss. These results suggest that promoting fallow lands and fragmented patches between rice fields could lead to more sustainable insect pest management in rice agroecosystems, potentially reducing the practice of prophylactic insecticide use.

Genome-wide identification, characterization, and expression analysis of the Ovate family protein in Oryza sativa under biotic and abiotic stresses

The Ovate Family Proteins (OFPs) are plant-specific transcription factors with a conserved OVATE domain. The OFPs regulate organ shape in Arabidopsis and many crops, including rice, tomato, and melon. However, little is known regarding the OFPs' potential role in regulating plant immune response to biotic/abiotic stresses. Herein, we reported the identification, bioinformatic, and Insilco analysis of OFPs in rice (Oryza sativa L). Thirty-one OsOFP genes were identified from the rice genome database and further divided into six subgroups based on their sequence similarities. Gene expression analysis in developmental stages indicated that some members of the OsOFP gene family displayed tissue-specific patterns. Enrichment of hormonal-related cis-acting elements and varied expression under phytohormones further validated their participation in hormone-mediated plant growth. The microarray expression analysis showed their possible involvement against salinity, drought, brown planthopper (BPH)_striped rice stemborer (SSB) (OsOFP25), and rice leaf folder (RLF) (OsOFP26) infestations. The higher expression of OsOFP25 in the OsWRKY65-OE line implies their key role in reproductive biology. These results provide a systematic analysis of the OsOFPs and lay a foundation for the functional characterization of this gene family.

A plant cytorhabdovirus modulates locomotor activity of insect vectors to enhance virus transmission

Transmission of many plant viruses relies on phloem-feeding insect vectors. However, how plant viruses directly modulate insect behavior is largely unknown. Barley yellow striate mosaic virus (BYSMV) is transmitted by the small brown planthopper (SBPH, Laodelphax striatellus). Here, we show that BYSMV infects the central nervous system (CNS) of SBPHs, induces insect hyperactivity, and prolongs phloem feeding duration. The BYSMV accessory protein P6 interacts with the COP9 signalosome subunit 5 (LsCSN5) of SBPHs and suppresses LsCSN5-regulated de-neddylation from the Cullin 1 (CUL1), hereby inhibiting CUL1-based E3 ligases-mediated degradation of the circadian clock protein Timeless (TIM). Thus, virus infection or knockdown of LsCSN5 compromises TIM oscillation and induces high insect locomotor activity for transmission. Additionally, expression of BYSMV P6 in the CNS of transgenic Drosophila melanogaster disturbs circadian rhythm and induces high locomotor activity. Together, our results suggest the molecular mechanisms whereby BYSMV modulates locomotor activity of insect vectors for transmission.

Beneficial interaction between rice stunt virus and its insect vector Nilaparvata lugens Stal based on life table

Beneficial interaction between rice stunt virus and its insect vector Nilaparvata lugens Stal based on life table

Expression Analysis Reveals Differentially Expressed Genes in BPH and WBPH Associated with Resistance in Rice RILs Derived from a Cross between RP2068 and TN1.

BPH (brown planthopper) and WBPH (white backed planthopper) are significant rice pests that often co-occur as sympatric species and cause substantial yield loss. Despite their genetic similarities, different host-resistance genes confer resistance against these two hoppers. The defense mechanisms in rice against these pests are complex, and the molecular processes regulating their responses remain largely unknown. This study used specific recombinant inbred lines (RILs) derived from a cross between rice varieties RP2068-18-3-5 (BPH- and WBPH-resistant) and TN1 (BPH- and WBPH-susceptible) to investigate the mechanisms of interaction between these planthoppers and their rice hosts. WBPH and BPH were allowed to feed on specific RILs, and RNA-Seq was carried out on WBPH insects. Transcriptome profiling and qRT-PCR results revealed differential expression of genes involved in detoxification, digestion, transportation, cuticle formation, splicing, and RNA processing. A higher expression of sugar transporters was observed in both hoppers feeding on rice with resistance against either hopper. This is the first comparative analysis of gene expressions in these insects fed on genetically similar hosts but with differential resistance to BPH and WBPH. These results complement our earlier findings on the differential gene expression of the same RILs (BPH- or WBPH-infested) utilized in this study. Moreover, identifying insect genes and pathways responsible for countering host defense would augment our understanding of BPH and WBPH interaction with their rice hosts and enable us to develop lasting strategies to control these significant pests.

Studies on Compatibility of Insecticides and Fungicides against Brown Plant Hopper and Blast in Rice

Field experiments conducted for evaluation of compatibility of insecticides and fungicides against brown planthopper and blast in rice revealed that pymetrozine in combination with tricyclazole and isoprothiolane and triflumezopyrim in combination with tricyclazole and isoprothiolane were found effective against brown plant hopper and blast and recorded higher grain yields (4872 kg/ha, 4873 kg/ha, 5014 kg/ha and 5088 kg/ha) compared to untreated control (3036 kg/ha). Neither insecticides nor fungicides lost their efficacy against target pest/disease when used as tank mixtures. Insecticides, pymetrozine and triflumezopyrim are compatible with tricyclazole and isoprothiolane fungicides with nil phytotoxicity and can be safely used as tank mixtures for simultaneous management of BPH and blast in rice.

Available cloned genes and markers for genetic improvement of biotic stress resistance in rice.

Biotic stress is one of the major threats to stable rice production. Climate change affects the shifting of pest outbreaks in time and space. Genetic improvement of biotic stress resistance in rice is a cost-effective and environment-friendly way to control diseases and pests compared to other methods such as chemical spraying. Fast deployment of the available and suitable genes/alleles in local elite varieties through marker-assisted selection (MAS) is crucial for stable high-yield rice production. In this review, we focused on consolidating all the available cloned genes/alleles conferring resistance against rice pathogens (virus, bacteria, and fungus) and insect pests, the corresponding donor materials, and the DNA markers linked to the identified genes. To date, 48 genes (independent loci) have been cloned for only major biotic stresses: seven genes for brown planthopper (BPH), 23 for blast, 13 for bacterial blight, and five for viruses. Physical locations of the 48 genes were graphically mapped on the 12 rice chromosomes so that breeders can easily find the locations of the target genes and distances among all the biotic stress resistance genes and any other target trait genes. For efficient use of the cloned genes, we collected all the publically available DNA markers (~500 markers) linked to the identified genes. In case of no available cloned genes yet for the other biotic stresses, we provided brief information such as donor germplasm, quantitative trait loci (QTLs), and the related papers. All the information described in this review can contribute to the fast genetic improvement of biotic stress resistance in rice for stable high-yield rice production.

Genotypic and phenotypic analysis of backcross inbred lines for brown plant hopper resistance in rice

Genotypic and phenotypic analysis of backcross inbred lines for brown plant hopper resistance in rice

Rice brown planthopper monitoring and detection by spectral reflectance: a review

Brown planthopper (BPH) has been one of the main pests of rice worldwide. Monitoring is important factor for determining attacks and estimating their effects. The traditional monitoring approach is usually conducted through visual observation and field scouting, with limitations such as subjectivity and time consumption. Remote sensing is an alternative pest monitoring method that covers a larger area in a shorter time. This paper discusses a remote-sensing method that uses a spectral approach to detect BPH attacks. Literature was filtered and processed using the PRISMA method. According to the spectral sensor, studies were classified into multispectral and hyperspectral sensors. Based on this scale, there are four studies on the panicle, leaf, canopy, and field levels. The model used single-wave reflectance and spectral indices as predictors. Various algorithms were used in the studies: linear regression, Principal Component Analysis, and Machine Learning to estimate the severity class, BPH Population density, and yield loss. A combination of spectral reflectance with other parameters, such as weather, fertilizer application, and infestation time, was conducted to improve the performance of the detection model. This review provides state-of-the-art spectral reflectance usage for detecting BPH attacks and opportunities for future development.

Molecular analysis of NlugCSP3 with behaviorally active ligands of the brown planthopper, Nilaparvata lugens (Hemiptera: Delphacidae)

The insect olfactory system is sensitive to the complicated chemical environment. Insect’s chemosensory proteins (CSPs) supposedly act as transport of plant volatiles across the sensillar lymph and competitive fluorescent binding assay was commonly used to test the binding affinities with various plant volatiles. However, extensive research to determine the physiological role of CSPs is necessary and helpful through binding interaction of a protein with the plant volatiles. In this comparative study, we employed phylogenetic analysis, fluorescence spectra, quenching mode, and thermodynamic force to characterize Nilaparvata lugens CSP3 (NlugCSP3). The phylogenetic tree revealed that amino acid sequence of NlugCSP3 showed extremely close similarities with Laodelphax striatella (LstrCSP10 & LstrCSP11) and Sogatella furcifera (SurCSP3). The Stern-Volmer (SV) curve of NlugCSP3 fluorescence quenching indicated that nonadecane and 2-tridecanone clearly quenched NlugCSP3 fluorescence as a stable static quenching mode. Meanwhile, α-terpinene and farnesene collided with NlugCSP3, instead of forming stable complexes. The thermodynamic analysis of NlugCSP3 revealed that spontaneous binding interaction occurred in nonadecane and 2-tridecanone and is driven primarily by hydrophobic interactions. This study not only provides the information about the binding interaction of protein with the volatiles, but also improves the efficient recognition of behaviorally elicited volatiles that could be used in the management of brown planthopper.

Screening of Rice Genotypes for their Reaction to Resistance against Brown Planthopper Nilaparvata lugens (Stal.)

Screening of Rice Genotypes for their Reaction to Resistance against Brown Planthopper Nilaparvata lugens (Stal.)

Molecular Diversity and Population Structure Analysis in Rice Genotype using SSR Markers

The use of advanced molecular technologies is one possible approach to understand their diversity. A study was undertaken to evaluate forty two rice genotype including six checks during kharif 2019. The result of the investigation was allele number was recorded for the five markers with an average of 2.6 allele per locus. Out of twenty five markers 12 markers showed highly PIC value. However, UPGMA cluster diagram mean of 67% level of similarity showed forty two accessions into 10 distinct clusters. Maximum cluster II had 13 genotypes followed by cluster IV, X, III and IX consisting of eleven, six three and two genotype respectively. Population structure analysis population inferred ancestry, 10 pure accessions were assigned to subgroup SG1 whereas 30 pure accessions were assigned to subgroup SG2 and two lines were assigned to admixture (AD). It was observed that the genotypes of subgroup 1 have brown planthopper resistant, whereas the genotypes of subgroup 2 have high yielding.

Large scale rice germplasm screening for identification of novel brown planthopper resistance sources.

The online version contains supplementary material available at 10.1007/s11032-023-01416-x.

Nicotine perturbs the microbiota of brown planthopper (Nilaparvata lugens stål Hemiptera: Delphinidae)

Bacterial symbionts exhibiting co-evolutionary patterns with insect hosts play a vital role in the nutrient synthesis, metabolism, development, reproduction, and immunity of insects. The brown planthopper (BPH) has a strong ability to adapt to various environmental stresses and can develop resistance to broad-spectrum insecticides. We aimed to investigate whether gut symbionts of BPH play a major role in the detoxification of insecticides and host fitness in unfavorable environments. Nicotine-treated rice plants were exposed to BPH (early stage) and the gut microbiome of the emerging female adults were analyzed using high throughput sequencing (HTS). Nicotine administration altered the diversity and community structure of BPH symbionts with significant increases in bacterial members such as Microbacteriaceae, Comamondaceae, Enterobacteriaceae, and these changes may be associated with host survival strategies in adverse environments. Furthermore, the in-vitro study showed that four intestinal bacterial strains of BPH (Enterobacter NLB1, Bacillus cereus NL1, Ralstonia NLG26, and Delftia NLG11) could degrade nicotine when grown in a nicotine-containing medium, with the highest degradation (71%) observed in Delftia NLG11. RT-qPCR and ELISA analysis revealed an increased expression level of CYP6AY1 and P450 enzyme activities in Delftia NLG11, respectively. CYP6AY1 increased by 20% under the action of Delftia and nicotine, while P450 enzyme activity increased by 18.1%. After CYP6AY1 interference, nicotine tolerance decreased, and the mortality rate reached 76.65% on the first day and 100% on the third day. Moreover, Delftia NLG11 helped axenic BPHs to increase their survival rate when fed nicotine in the liquid-diet sac (LDS) feeding system. Compared with axenic BPHs, the survival rate improved by 25.11% on day 2% and 6.67% on day 3. These results revealed an altered gut microbiota and a cooperative relationship between Delftia NLG11 and CYP6AY1 in nicotine-treated BPH, suggesting that insects can adapt to a hostile environment by interacting with their symbionts and providing a new idea for integrated pest management strategies.

Mitigation of Abiotic and Biotic Stress Using Plant Growth Regulators in Rice

Split plot design experiments were conducted to assess the performance of growth regulating compounds for mitigating moisture stress and the incidence of Brown Plant Hopper (BPH) in rice. The main plot treatments (4) comprised moisture stress free control (M1), moisture stress during panicle initiation stage alone (M2), moisture stress during flowering stage alone (M3), and moisture stress during both panicle initiation and flowering stages (M4). The sub-plot treatments (5) were foliar application of growth regulating compounds including chlormequat chloride at 200 ppm (S1), mepiquat chloride at 200 ppm (S2), brassinolide at 0.1 ppm (S3), pink pigmented facultative methylotrophs (PPFM) at 1% (S4), and no spray control (S5). The reduced plant growth attributes were registered under moisture stress at both panicle initiation and flowering stages. The spraying of 1% PPFM during the flowering or both at panicle initiation and flowering stages led to better performance than the other treatments. Also, spraying 1% PPFM brought down the population of BPH to a considerable level during both years of experiments. This suggests that spraying 1% PPFM in the post-flowering stage helps to mitigate the ill effect the moisture stress and BPH incidence.

Intensitas Serangan Dan Fluktuasi Populasi Wereng Batang Coklat Nilaparvata lugens Dengan Beberapa Teknik Pengendalian Pada Tanaman Padi

The brown planthopper is an important pest in rice cultivation which acts as a vector for viruses that cause grass stunt and hollow stunt disease which can cause rice plants to die or reduce production to the detriment of farmers. This study aimed to obtain a pest control technique capable of suppressing the population and intensity of brown planthopper attacks on rice plants. This study is an experimental study using single-factor Randomized Block Design (RBD) with 4 treatments and 6 replications: C (Control); CC (Combination Control); BC (Biointensive Control); SC (Synthetic Control). The analysis results obtained showed that the SC treatment gave the lowest attack intensity value of 0.00% - 28.67% with a total population of 0 - 89 individuals followed by CC (1.33% - 44.67%) with a total population of 2-114 individuals, BC (2.00%-46%) with a total population of 3 - 103 individuals, and C (2.00% -45.33%) with a total population of 3 - 102 individuals. Synthetic control can be recommended as an alternative pest control technique in reducing the intensity of brown planthopper attacks.