Brown Planthopper Nilaparvata Lugens Research Articles

Impact of Abiotic Factors on the Incidence of Brown Plant Hopper Nilaparvata lugens Stal in Rice Crop at Cuddalore District, Tamil Nadu, India

Rice is a dietary staple of more than half of world’s population, and more than 90% of world’s rice is grown and consumed in Asia alone but faces significant threat from insect pests most importantly Brown plant hopper (BPH), Nilaparvata lugens Stal, consider to be a major insect pest of rice. This study showcases the correlation between weather parameters and BPH infestation in rice crop grown in two Kharif (rainy) and two Rabi (winter) seasons of 2022 and 2023 in Chidambaram, Tamil Nadu, India. Non-resistant rice varieties (ADT 43 and ADT 54) were used. BPH population and weather data (maximum and minimum temperature, relative humidity, sunshine hours, rainfall, and wind speed) were collected weekly. In all the seasons the BPH population ranged from 0.0 to 8.2 at its peak in our study area. Results showed that BPH populations were higher during kharif seasons compared to rabi seasons. Maximum temperature and sunshine hours exhibited a positive correlation with BPH population, while rainfall and minimum temperature were negatively correlated. By taking into account these weather parameters, farmers can predict and monitor fluctuations in pest populations. This enables them to apply pesticides strategically, only when economically justified, and to implement a range of integrated pest management techniques.

Insecticidal activities of three recombinant venom proteins of the predatory stink bug, Arma custos.

Widespread resistance of insect pests to insecticides and transgenic crops in the field is a significant challenge for sustainable agriculture, and calls for the development of novel alternative strategies to control insect pests. One potential resource for the discovery of novel insecticidal molecules is natural toxins, particularly those derived from the venoms of insect predators. In this study, we identified three insecticidal proteinaceous toxins from the venom glands (VGs) of the predatory stink bug, Arma custos (Hemiptera: Asopinae). Transcriptomic analysis of A. custos VGs revealed 151 potentially secreted VG-rich venom proteins. Three VG-rich venom proteins (designated AcVP1 ~ 3) were produced by overexpression in Escherichia coli. Injection of the recombinant proteins into tobacco cutworm (Spodoptera litura) larvae showed that all of the three recombinant proteins caused paralysis, liquefaction and death. Injection of recombinant proteins into rice brown planthopper (Nilaparvata lugens) nymphs showed higher insecticidal activities, among which a trypsin (AcVP2) caused 100% mortality postinjection at 1.27 pmol mg-1 body weight. A natural toolkit for the discovery of insecticidal toxins from predatory insects has been revealed by the present study. © 2024 Society of Chemical Industry.

Identification of a vital transcription factor of the alanine aminotransferase in the brown planthopper and its upstream regulatory pathways

The brown planthopper (Nilaparvata lugens) is an important insect pest of rice, and can rapidly adapt to insect-resistant rice varieties. In our previous studies, alanine aminotransferase in N. lugens (NlALT) was found to play an important role in the adaptation of the brown planthopper to resistant rice IR36. Here, we further identified CCAAT/enhancer binding protein (NlC/EBP) as a vital transcription factor of NlALT. Nlp38b in the MAPKs pathway regulated the expression of NlALT by influencing the phosphorylation level of NlC/EBP. In addition, we found that NlGRL101, a G protein-coupled receptor (GPCR), was significantly higher expressed in the N. lugens population adapted to IR36 (P-IR36). After knockdown of NlGRL101 through RNAi in P-IR36 population, lower expressions of Nlp38b and NlC/EBP, along with reduced phosphorylation levels of Nlp38b and NlC/EBP were observed; moreover, NlALT activity and honeydew amount were decreased by 15.68% and 76.08%, respectively. These results indicated that insect-resistant rice IR36 induced expression of NlGRL101, which enhanced expression of NlALT through Nlp38b and NlC/EBP. These findings are helpful for better understanding of insect adaptation to resistant crop varieties.

NPF and sNPF can regulate the feeding behaviour and affect the growth and antioxidant levels of the rice brown planthopper, Nilaparvata lugens.

Neuropeptide F (NPF) and short neuropeptide F (sNPF) are important neuropeptides and mainly affect feeding behaviour of insects. However, the regulation of insect feeding behaviour by NPF and sNPF appears to differ between species, and it is not clear how NPF and sNPF regulate the food intake of the brown planthopper (Nilaparvata lugens). Therefore, the functions of NPF and sNPF in regulating food intake and affecting the growth and antioxidant levels of N. lugens fed on host rice plants were investigated by knocking down NPF and sNPF respectively and simultaneously knocking down both of them by RNA interference. The results showed that NPF and sNPF were mainly expressed in the head of N. lugens, and N. lugens increased food intake after NPF and sNPF were knocked down, which was reflected in the prolonged duration of N4a and N4b waves in the electrical penetration graph (EPG) experiment after knocking down NPF and sNPF. In addition, knocking down NPF and sNPF led to the increase of body weight and mortality of N. lugens, and also led to the increase of antioxidant level of N. lugens. So it was concluded that NPF and sNPF could regulate food intake, maintain body weight stability and oxidative balance in N. lugens. Our study clarified the molecular mechanism of NPF and sNPF regulating feeding behaviour and affect the growth and antioxidant level of N. lugens.

Functional Analysis of CPSF30 in Nilaparvata lugens Using RNA Interference Reveals Its Essential Role in Development and Survival.

The brown planthopper (Nilaparvata lugens) is a major pest threatening global rice production, significantly reducing yields annually. As N. lugens increasingly develops resistance to conventional control methods, such as chemical pesticides, there is an urgent need for innovative and sustainable pest management strategies. Cleavage and Polyadenylation Specificity Factor 30 (CPSF30) is a key protein involved in mRNA 3' end processing, yet its function in N. lugens remains poorly understood. This study aims to elucidate the role of CPSF30 in the growth and development of N. lugens and evaluate its potential as a target for RNA interference (RNAi)-based pest control strategies. We cloned and characterized the cDNA sequence of NlCPSF30, which encodes a protein of 341 amino acids containing five CCCH zinc-finger domains and two CCHC zinc-knuckle domains. Sequence alignment revealed that NlCPSF30 is highly conserved among insect species, particularly in the zinc-finger domains essential for RNA binding and processing. Phylogenetic analysis showed that NlCPSF30 is closely related to CPSF30 proteins from other hemipteran species. Expression analysis indicated that NlCPSF30 is most highly expressed in the fat body and during the adult stage, with significantly higher expression in females than in males. RNAi-mediated silencing of NlCPSF30 in third-instar nymphs resulted in severe phenotypic abnormalities, including disrupted molting and increased mortality following injection of double-stranded RNA (dsRNA) targeting NlCPSF30. Moreover, it influenced the expression of genes associated with hormone regulation, namely NlHry, NlE93, and NlKr-h1. These results suggest that NlCPSF30 is integral to critical physiological processes, with its disruption leading to increased mortality. Our findings identify NlCPSF30 as an essential gene for N. lugens' survival and a promising target for RNAi-based pest management strategies. This study provides a valuable molecular target and theoretical insights for developing RNAi-based control methods against N. lugens.

AKH/AKHR signalling system induced antioxidant response mediated by entomopathogenic fungi in Nilaparvata lugens (Stål)

The brown planthopper Nilaparvata lugens is one of the most economically important rice crop pests in Asia. Entomopathogenic fungi (EPF) have been developed as a biological control of N. lugens. Insect adipokinetic hormones (AKHs) are pleiotropic hormones that play a protective role in response to oxidative stress. However, the role of AKH in the anti-oxidative response of N. lugens to EPFs (Metarhizium anisopliae and Beauveria bassiana) infection remains largely unexplored. In this study, the results of relative enzyme activities and expression levels of antioxidant enzymes demonstrated the response of the antioxidant system of N. lugens to EPF infection. Additionally, the expression of AKH/adipokinetic hormone receptor (AKHR) also induced responding to the infection of EPF in N. lugens. Silencing NlAKH or NlAKHR significantly increased mortality in nymphs treated with fungi compared with controls, whereas the injection of AKH peptide decreased mortality. Further research indicated that the AKH/AKHR system positively influenced antioxidant enzymes, potentially involving the transcription factors forkhead-box O and Cap’ n’ collar C. These findings provide an important theoretical basis for developing new pest control agents targeting the neuropeptide AKH and offer new insights for mitigating brown planthopper resistance and promoting green control strategies.

Nitrogen input reduces the physical defense of rice plant against planthopper, Nilaparvata lugens (Hemiptera: Delphacidae).

Nitrogen has important effects on plant growth and defense. Although studies on the alternation in plant chemical defense by nitrogen fertilization have been extensively reported, how it affects physical defense is poorly understood. Two rice (Oryza sativa L.) (Poales: Poaceae) varieties (LDQ7 and YLY1) were applied with varying nitrogen regimes (0.90 and 180kg ha-1) to study their physical defense against the brown planthopper (BPH) Nilaparvata lugens (Hemiptera: Delphacidae) in this study. Results of the electrical penetration graph showed that BPH searching and penetrating duration time was shortened with increasing nitrogen application. Also, the tubercle papicle of rice leaves decreased with increasing nitrogen application, while rice leaves' surface structure and waxy composition changed with increasing nitrogen application. In field experiments, BPH populations increased with the application of nitrogen fertilizer. These findings suggest that nitrogen input can affect plant-insect interactions by reducing the physical defense of plants, which provides new ideas for the organic combinations of yield increase and pest control in rice fields.

Tendency to mate with short-winged partner of the brown planthopper Nilaparvata lugens (Hemiptera: Delphacidae).

Wing dimorphism is a distinguishing characteristic of brown planthopper Nilaparvata lugens (Stål) populations, wherein adults exhibit 2 distinct morphs: long-winged and short-winged. The presence of long-winged individuals often heralds the onset of migration, while short-winged morphs signify high reproduction and can be associated with population outbreaks. This phenomenon underscores the adaptability of these insects in response to environmental cues and their impact on agricultural ecosystems. Wing morphs of N. lugens are controlled by genetical and environmental factors. Mate choice between long and short-winged adults affects wing morphs of offspring. In this study, we found that the wild population had no persistent preference for choosing long-winged or short-winged adults to mate. But in 2 multigenerational selected lineages for long and short-winged morphs, the short-winged males preferred to short-winged females to mate and the long-winged males had no preference. In the nearly pure-bred lineages of long-winged and short-winged morphs, both wing morphs of females preferred for short-winged males. Purification of wing morph lineages enhanced mating preference for short-winged partners. When the wing developmental gene InR1 or InR2 was interfered by RNAi, the pure-bred lineage of long-winged morph mainly produced short-winged adults and the short-winged morphs produced long-winged adults, and these adults exhibited preference to mate with short-winged partners. The tendency to mate with short-winged morphs leads to more short-winged offspring which easily causes the rapid growth of populations.

Feeding Behavior of Brown Planthopper (Nilaparvata lugens) on Pigmented Rice Monitored by Electrical Penetration Graph (EPG)

Feeding Behavior of Brown Planthopper (Nilaparvata lugens) on Pigmented Rice Monitored by Electrical Penetration Graph (EPG)

Serotonin suppresses intraspecific aggression in an agrobiont spider, Pardosa pseudoannulata, without affecting predation on insects.

Spiders are an abundant group of natural enemies preying on insect pests in agroecosystem. But their potential in biological control has not been fully realized due to difficult mass production. One hindrance is the intense intraspecific aggression in spiders. Neurotransmitters such as serotonin play important roles in modulating aggression. Here, we investigated the regulatory function of serotonin (5-hydroxytryptamine [5-HT]) signaling in the intraspecific aggression in a wandering spider Pardosa pseudoannulata (Araneae, Lycosidae). The aggression was quantified with 5 escalated aggression behaviors as approach, chasing, lunging, boxing, and biting. Virgin (VG) females exhibited higher aggression levels but less 5-HT content than post-reproductive (PR) females. Systemic increase of 5-HT via 5-HT injection decreased aggression, while decrease of 5-HT via RNA interference (RNAi) of the tryptophan hydroxylase gene, increased aggression. The involvement of the four 5-HT receptors were determined via individual or combined RNAi. Co-RNAi of the three 5-HT1 genes increased overall aggression with decreased incidents of approach, chasing, lunging, and increased biting. RNAi of 5-HT1B decreased approach and increased biting, whereas RNAi of 5-HT1A or 5-HT1C did not affect aggression. RNAi of 5-HT7 decreased approach only. Therefore, different 5-HT receptor types contribute to different aspects of the inhibitory effects of 5-HT on aggression and provide several pharmacological targets for manipulating spider aggression. 5-HT injection did not affect spiders' predation on their insect prey, the brown planthopper Nilaparvata lugens. The findings reveal 1 neuronal mechanism regulating intraspecific aggression in spiders and provide an insight in developing aggression suppression strategies for spider mass rearing.

RNAseq-Based Carboxylesterase Nl-EST1 Gene Expression Plasticity Identification and Its Potential Involvement in Fenobucarb Resistance in the Brown Planthopper Nilaparvata lugens.

Carbamate insecticides have been used for over four decades to control brown planthopper, Nilaparvata lugens, but resistance has been reported in many countries, including the Republic of Korea. The bioassay results on resistance to fenobucarb showed that the LC50 values were 3.08 for the susceptible strain, 10.06 for the 2015 strain, and 73.98 mg/L for the 2019 strain. Compared to the susceptible strain, the 2015 and 2019 strains exhibited resistance levels 3.27 and 24.02 times higher, respectively. To elucidate the reason for the varying levels of resistance to fenobucarb in these strains, mutations in the acetylcholinesterase 1 (ACE1) gene, the target gene of carbamate, were investigated, but no previously reported mutations were confirmed. Through RNA-seq analysis focusing on the expression of detoxification enzyme genes as an alternative resistance mechanism, it was found that the carboxylesterase gene Nl-EST1 was overexpressed 2.4 times in the 2015 strain and 4.7 times in the 2019 strain compared to the susceptible strain. This indicates a strong correlation between the level of resistance development in each strain and the expression level of Nl-EST1. Previously, Nl-EST1 was reported in an organophosphorus insecticide-resistant strain of Sri Lanka 2000. Thus, Nl-EST1 is crucial for developing resistance to organophosphorus and carbamate insecticides. Resistance-related genes such as Nl-EST1 could serve as expression markers for resistance diagnosis, and can apply to integrated resistance management of N. lugens.

The symbiont Acinetobacter baumannii enhances the insect host resistance to entomopathogenic fungus Metarhizium anisopliae

Major symbiotic organisms have evolved to establish beneficial relationships with hosts. However, understanding the interactions between symbionts and insect hosts, particularly for their roles in defense against pathogens, is still limited. In a previous study, we proposed that the fungus Metarhizium anisopliae can infect the brown planthopper Nilaparvata lugens, a harmful pest for rice crops. To expand on this, we investigated changes in N. lugens’ intestinal commensal community after M. anisopliae infection and identified key gut microbiotas involved. Our results showed significant alterations in gut microbiota abundance and composition at different time points following infection with M. anisopliae. Notably, certain symbionts, like Acinetobacter baumannii, exhibited significant variations in response to the fungal infection. The decrease in these symbionts had a considerable impact on the insect host’s survival. Interestingly, reintroducing A. baumannii enhanced the host’s resistance to M. anisopliae, emphasizing its role in pathogen defense. Additionally, A. baumannii stimulated host immune responses, as evidenced by increased expression of immune genes after reintroduction. Overall, our findings highlight the significance of preserving a stable gut microbial community for the survival of insects. In specific conditions, the symbiotic microorganism A. baumannii can enhance the host’s ability to resist entomopathogenic pathogens through immune regulation.

RNAi-mediated silencing of NlGRP3 augments the insecticidal virulence of Metarhizium anisopliae to the brown planthopper Nilaparvata lugens

The rapid development of insecticide resistance reinforces the urgent need to develop eco-friendly strategies for controlling Nilaparvata lugens (brown planthopper, BPH), the most destructive insect pest of rice. Both entomopathogens and RNA interference (RNAi) provide attractive alternatives to chemical insecticides. In this study, we demonstrated the synergistic potential of the combination use of entomopathogen- and RNAi-mediated approaches to control BPH. The β-1, 3-glucan recognition protein (βGRP) encoding gene NlGRP3 was identified and its potential role in immune defense was characterized in BPH. The open reading frame (ORF) of NlGRP3 is 1740 bp in length, encoding a 65.8 kDa protein with conserved CBM39 and GH16 domains that typically existed in the βGRP family members. NlGRP3 was shown to be differentially expressed across developmental stages and highly transcribed in the immune responsive tissues haemolymph and fat body. Topical infection with a fungal entomopathogen Metarhizium anisopliae could significantly up-regulate its expression level. RNAi-mediated silencing of NlGRP3 resulted in significantly decreased survival rate and increased susceptibility to fungal challenge in the fifth-instar BPH nymphs. The greatly enhanced mortality of NlGRP3-silenced BPH following fungal infection might be in part directly due to the immune suppression by down-regulating expressions of antimicrobial peptide genes and the imbalance of the bacterial community harboring in BPH body. Our results highly demonstrated that suppressing the insect innate immune defense through RNAi targeting the immune-related genes could effectively strengthen the biocontrol efficacy of fungal entomopathogens, providing clues to the combination use of RNAi and entomopathogens as a promising approach for BPH control.

Effect of biotic and abiotic factors on the population dynamics of Nilaparvata lugens in the middle Gangetic Plains of India

Aim: To investigate the effect of biotic and abiotic factors on the population dynamics of brown planthopper Nilaparvata lugens (Stal) (Hemiptera: Delphacidae) in the middle Gangetic plains of India. Methodology: Field trials were conducted in the middle Gangetic plains of India at Agricultural Research Farm, B.H.U., Varanasi, Uttar Pradesh, India during Kharif season of 2018 and 2019 on the variety Swarna sub-1 to study the population dynamics and certain biotic and abiotic interaction with brown planthopper. Results: During Kharif 2018 and 2019, the highest mean number of brown planthopper population (45.00 ± 2.31 and 39.33 ±1.82 nos., respectively) were recorded during September in both seasons. Abiotic factors such as rainfall (r = - 0.556), relative humidity in the morning (r = 0.476), maximum temperature (r = 0.511), and sunshine hour (r = - 0.546) influenced planthopper population dynamics, and predictions were made with reasonable accuracy (R2 = 0.89) using the principal component regression analysis technique. Crop phenology was the most influential biotic factor on pest population density. The crop's booting stage had the highest incidence of planthoppers. Three different predatory populations (wolf spider, damselfly and ladybird beetle) were observed to feed on planthoppers in Kharif 2018 and four different predatory populations (wolf spider, damselfly, ladybird beetle and green mirid bug) were observed to feed on planthoppers in Kharif 2019, resulting in a reduction in crop pest density. Interpretation: These findings can be used to develop the precise management strategies for brown planthopper in the rice ecosystem. Key words: Abiotic, Biotic factors, Brown planthopper, Crop phenology, Middle Gangetic Plains, Natural enemies, Rice

Reduction of the natural enemy population by deltamethrin and imidacloprid leads to the resurgence of brown planthopper (Nilaparvata lugens, Hemiptera: Delphacidae (Stal)) in rice

Reduction of the natural enemy population by deltamethrin and imidacloprid leads to the resurgence of brown planthopper (Nilaparvata lugens, Hemiptera: Delphacidae (Stal)) in rice

Molecular identification and eco-friendly management of rice brown planthoppers in Bangladesh

Infestation by various insect pests is the main constraint for growing rice where rice brown planthopper (Nilaparvata lugens Stål) can severely damage rice plants directly through feeding. Therefore, the study aims to detect rice brown planthoppers (BPH) and provide environment-friendly management tactics to mitigate the problem which caused by brown planthoppers. The BPH samples were collected from rice fields of different locations in the Patuakhali of Bangladesh for molecular identification. A molecularly single species of rice brown planthopper, Nilaparavata lugens was identified using mitochondrial cytochrome oxidase subunit I (mtCOI) universal marker. The nucleotide sequences of collected samples were compared with other nucleotide sequences from the GenBank database of NCBI, which make single clades in the phylogenetic tree at an insignificant distance. Moreover, brown planthopper management observations were recorded in laboratory conditions after providing an artificial diet with different treatments of plant-based insecticides Neem oil (1 %, 5 %, and 10 %), Castor oil (1 %, 5 %, and 10 %) where only 20 % sucrose solution was used as negative control and Abamectin (1 %, 5 % and 10 %) were also used as a positive control for comparing the efficacy of plant-based insecticides on rice brown planthoppers. The results showed the highest mortality (100 %) of rice brown planthoppers was recorded by Abamectin 10 %, followed by Abamectin 5 %. Neem 10 % performed better than Abamectin 1 % during 1st hour. Initial after exposure of 2nd hour for Abamectin 1 % revealed greater mortality (59 %) than Neem 10 %. Neem 5 % showed less effect on mortality in brown planthopper than Neem 10 % but was higher than Neem 1 % during 6 h of observation. The Castor oil of 10 % caused higher mortality than the Castor of 5 % but not up to the marks of Abamectin and different concentrations of Neem oil. Castor oil of 1 % and control have shown no mortality of brown planthopper for 6 h of observation.

Effects of CO2 elevation on life-history traits of two insecticide-resistant strains of planthopper Nilaparvata lugens on rice.

We made separate experiments to examine life-history traits and activities of protective enzymes as affected by carbon dioxide (CO2) elevation to 780 μL/L as compared to 390 μL/L in imidacloprid- or buprofezin-resistant strains of the brown planthopper (BPH) Nilaparvata lugens. We found an interaction effect between resistance and the CO2 level on the nymphal survival and duration in both resistant strains. Nymphal durations in both resistant strains were much shorter in the resistant than susceptible BPH at 780 μL/L but similar between them or slightly shorter in the resistant than susceptible BPH at 390 μL/L. Nymphal survival was lower for imidacloprid-resistant than its susceptible BPH at 390 μL/L but higher at 780 μL/L; it stayed unaffected by the CO2 elevation in buprofezin-resistant BPH. We did not observe an interaction effect between resistance and the CO2 level on major reproductive parameters in both resistant strains. But the 2 strains were not consistent across CO2 levels in all parameters. Our measurements of protective enzyme activities of superoxide dismutase, catalase, and peroxidase showed an interaction between resistance and the CO2 level. Overall, these enzymes became similar in activity between resistant and susceptible BPH at 780 μL/L compared to 390 μL/L and the change was more distinct in the imidacloprid- than buprofezin-resistant BPH strains. Our findings suggest that CO2 elevation can affect life-history traits of insecticide-resistant BPH, while the effect may vary depending on the kind of insecticides it is resistant to.

Interaction of Predatory Ladybird Beetle, Micraspis discolor with Nilaparvata lugens throughout Paddy Growing Seasons

Coccinellidae is a high-interest family that has performed well and is widely distributed. It is valuable in economic service because it acts as an agricultural biological control agent. The Micraspis discolor (Syn=Verania) (Coleoptera: Coccinellidae) is a successful omnivorous predator in rice ecosystem and functions well as a general biological control for maintaining the population of brown planthopper (BPH) (Nilaparvata lugens), the major rice pest worldwide. Studies of natural enemies’ abundance are necessary to increase the practical use of biological control in agriculture. This study investigated the abundance correlation of M. discolor (prey) and rice pest N. lugens (prey) from two different geographical areas of rice fields in west and south Peninsular Malaysia. The cyclone lightrap and sweep net method succeeded in collecting 185 individuals of M. discolor and N. lugens. The study indicated that M. discolor, and the N. lugens collected from Selangor were more numerous than Johor in the ripening phase than in the reproductive and vegetative phases. M. discolor can be found in all stages of rice growth. There are positive correlations between M. discolor and N. lugens in both localities throughout the rice growing season. The positive correlation highlighted that the number of pests has increased parallel to the number of predators and vice versa. The use of M. discolor as a predator is essential in agriculture, along with the treatment of a healthy ecosystem landscape of diverse vegetation combinations, which helps to reduce the use of pesticides.

Transcriptome-wide N6-methyladenosine profiling reveals growth-defense trade-offs in the response of rice to brown planthopper (Nilaparvata lugens) infestation.

N6-Methyladenosine (m6A) is a common messenger RNA (mRNA) modification that affects various physiological processes in stress responses. However, the role of m6A modifications in plants responses to herbivore stress remains unclear. Here, we found that an infestation of brown planthopper (Nilaparvata lugens) female adults enhanced the resistance of rice to N. lugens. The m6A methylome analysis of N. lugens-infested and uninfested rice samples was performed to explore the interaction between rice and N. lugens. The m6A methylation mainly occurred in genes that were actively expressed in rice following N. lugens infestation, while an analysis of the whole-genomic mRNA distribution of m6A showed that N. lugens infestation caused an overall decrease in the number of m6A methylation sites across the chromosomes. The m6A methylation of genes involved in the m6A modification machinery and several defense-related phytohormones (jasmonic acid and salicylic acid) pathways was increased in N. lugens-infested rice compared to that in uninfested rice. In contrast, m6A modification levels of growth-related phytohormone (auxin and gibberellin) biosynthesis-related genes were significantly attenuated during N. lugens infestation, accompanied by the down-regulated expression of these transcripts, indicating that rice growth was restricted during N. lugens attack to rapidly optimize resource allocation for plant defense. Integrative analysis of the differential patterns of m6A methylation and the corresponding transcripts showed a positive correlation between m6A methylation and transcriptional regulation. The m6A modification is an important strategy for regulating the expression of genes involved in rice defense and growth during rice-N. lugens interactions. These findings provide new ideas for formulating strategies to control herbivorous pests. © 2024 Society of Chemical Industry.

Exploring the Resistance of Pigmented Rice to Brown Planthopper (Nilaparvata lugens Stål) by Phenotypic and Genotypic Analyses

Developing new pigmented rice varieties that meet consumers' preferences requires addressing resistance to brown planthopper (BPH), a highly destructive insect pest of rice. To effectively manage this pest, it is essential to explore BPH resistance genes from rice germplasms and incorporate them into elite varieties. The objective of this study was to identify the source of resistance among local and improved pigmented rice varieties in Indonesia against field BPH. Furthermore, the study aimed to characterize their genetic diversity using molecular markers associated with Bph genes and functional markers for these genes. Eighty-eight local varieties from the Indonesian Agricultural Gene Bank, collected across 18 provinces between 1971 and 2019, and four improved varieties, were evaluated using the standard seed box screening test method. Among these entries, 6 local accessions and 1 improved variety exhibited moderate resistance. Genetic analysis of these entries and three randomly selected susceptible entries using 12 SSR and InDel markers associated with Bph gene loci showed that the moderately resistant entries had higher allele numbers (11 to 13) compared to the susceptible entries (4 to 7). These markers could distinguish the resistant group from the susceptible ones in cluster analysis. Genotyping using functional markers further showed that the moderately resistant entries had 2 to 4 combinations of Bph genes. In contrast, the susceptible entries contained neither Bph genes nor only one gene. Local accessions with a 2 to 4 Bph gene combination can be donors of BPH resistance in improving pigmented rice varieties.