Characterization of heat shock protein 70 transcript from Nilaparvata lugens (Stål): Its response to temperature and insecticide stresses

De novo Transcriptomic analysis to unveil the deltamethrin induced resistance mechanisms in Callosobruchus chinensis (L.)

The use of synthetic insecticides has been crucial in the management of insect pests however the extensive use of insecticides can result in the development of resistance. Callosobruchus chinensis is a highly destructive pest of stored grains, it's a major feeder and infests a range of stored grains that are vital to both global food security and human nutrition. We extensively investigated gene expression changes of adults in response to deltamethrin to decipher the mechanism behind the insecticide resistance. The analysis of gene expression revealed 25,343 unigenes with a mean length of 1,435 bp. All the expressed genes were identified, and analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Exposure to deltamethrin (4.6 ppm) causes 320 differentially expressed genes (DEGs), of which 280 down-regulated and 50 up-regulated. The transcriptome analysis revealed that DEGs were found to be enriched in pathways related to xenobiotics metabolism, signal transduction, cellular processes, organismal systems and information processing. The quantitative real-time PCR was used to validate the DEGs encoding metabolic detoxification. To the best of our knowledge, these results offer the first toxicity mechanisms enabling a more comprehensive comprehension of the action and detoxification of deltamethrin in C. chinensis.

Characterizing Three Heat Shock Protein 70 Genes of Aphis gossypii and Their Expression in Response to Temperature and Insecticide Stress

Aphis gossypii is a highly polyphagous pest that causes substantial agricultural damage. Temperature and insecticides are two major abiotic stresses affecting their population abundance. Heat shock proteins play an essential role in cell protection when insects are exposed to environmental stresses. Three ApHsp70 genes were cloned from A. gossypii, and characterized their molecular features and expression profiles in response to temperature and insecticide stress. The deduced amino acid sequences of these proteins exhibited characteristic Hsp70 family signatures, and their tissue-specific expression patterns revealed their highest activity to be in the salivary glands under 35 °C. The temperature inductive assay further indicated that the expression of the three ApHsp70 genes was markedly upregulated under heat stress but not under cold shock. Furthermore, exposure to LC25 and LC50 concentrations of three insecticides triggered the upregulation of these ApHsp70 genes. The RNA interference (RNAi)-mediated suppression of ApHsp68 expression heightened cotton aphid's susceptibility to insecticides (acetamiprid and sulfoxaflor). Moreover, our study found that the sulfoxaflor-resistant strain of A. gossypii (Sul-R) displayed a higher survival rate compared with the sulfoxaflor-sensitive strain (Sul-S) under heat shock conditions. These results suggest that these three ApHsp70 genes play an essential role in response to both heat and insecticide stress.

Comparative transcriptomic and metabolomics analysis of ovary in Nilaparvata lugens after trehalase inhibition

The fecundity of Nilaparvata lugens (brown planthopper) is influenced by trehalase (TRE). To investigate the mechanism by which trehalose affects the reproduction of N. lugens, we conducted a comparative transcriptomic and metabolomic analysis of the ovaries of N. lugens following injection with dsTREs and validamycin (a TRE inhibitor). The results revealed that 844 differentially expressed genes (DEGs) were identified between the dsGFP and dsTREs injection groups, with 317 up-regulated genes and 527 down-regulated genes. Additionally, 1451 DEGs were identified between the water and validamycin injection groups, with 637 up-regulated genes and 814 down-regulated genes. The total number of DEGs identified between the two comparison groups was 236. The overlapping DEGs were implicated in various biological processes, including protein metabolism, fatty acid metabolism, AMPK signaling, mTOR signaling, insulin/insulin-like growth factor signaling (IIS), the tricarboxylic acid (TCA) cycle, oxidative phosphorylation, and the cellular process of meiosis in oocytes. These results suggest that the inhibition of TRE expression may lead to alterations in ovarian nutrient and energy metabolism by modulating glucose transport and affecting amino acid metabolic pathways. These alterations may influence the reproduction of N. lugens by modulating reproductive regulatory signals. These findings provide robust evidence supporting the mechanism through which trehalase inhibition reduces the reproductive capacity of N. lugens.

From molecular to physiological responses: improved stress tolerance and longevity in Drosophila melanogaster under fluctuating thermal regimes

Climate change introduces greater thermal variability, profoundly affecting ectothermic species whose body temperatures rely heavily on the environment. Understanding the physiological and metabolic responses to such variability is crucial for predicting how these species will cope with changing climates. This study investigates how chronic thermal stress impacts mitochondrial metabolism and physiological parameters in Drosophila melanogaster, hypothesizing that a fluctuating thermal regime (FTR) activates protective mechanisms enhancing stress tolerance and longevity. To test this, Drosophila were exposed to constant 24°C or to an FTR of 24°C:15°C (day:night) cycle following an initial 5 day period at 24°C. The FTR group exhibited rapid transcript level changes after the first day of FTR, particularly those related to heat shock proteins, mitophagy and regulatory factors, which returned to initial levels after 5 days. Mitochondrial respiration rates initially decreased after 1 and 2 days of FTR, then recovered by day 5, indicating rapid acclimation. Enhanced antioxidant enzyme activities were observed early in the FTR group, after 1 day for mtSOD and SODcyt+ext and 3 days for both SOD and catalase, followed by a decline by day 5, suggesting efficient oxidative stress management. The FTR group showed lower CTmax on day 3, reflecting possible physiological strain at that time point, and complete recovery by day 5. Longevity increased under FTR, highlighting the activation of protective mechanisms with beneficial long-term effects. These results suggest that FTR prompts a temporal succession of rapid physiological adjustments at different levels of organisation, enhancing long-term survival in D. melanogaster.

Comparative Transcriptome Analysis Highlights the Role of NlABCG14 in the Honeydew Production of Virulent Brown Planthoppers (Nilaparvata lugens Stål) to Resistant Rice Variety

Brown planthoppers (BPHs, Nilaparvata lugens Stål) are a major threat to rice cultivation in Asia, necessitating the development of pest-resistant varieties for effective management. However, the adaptability of BPHs has resulted in the development of virulent populations, such as biotype Y BPHs, which exhibit significant virulence against the rice variety YHY15 that harbors the resistance gene Bph15. The various response mechanisms of BPH populations to resistant rice varieties are critical yet underexplored. Via RNA sequencing, the present study identified distinct transcriptional profiles in avirulent (biotype 1) and virulent (biotype Y) BPH nymphs both before and after feeding on YHY15 rice. Our findings revealed differential expression patterns of gene clusters involved in protein synthesis, hydrolysis, fatty acid biosynthesis, metabolism, cuticle composition, and translocation. Further analysis elucidated changes in the expression of genes associated with longevity and structural components of cuticles, highlighting specific disruptions in both biotype 1 and biotype Y BPHs. Moreover, the two biotypes showed differences in the expression level of genes involved in ATP-binding cassette (ABC) transporters. A functional assessment of ABC transporter genes revealed a role of NlABCG14 in the honeydew production of biotype Y BPHs to YHY15 rice, without impacting their survival and developmental dynamics. These insights deepen our understanding of the mechanisms of virulent BPHs response to resistant rice varieties and highlight potential targets for improving pest management strategies.

Insight into Rice Resistance to the Brown Planthopper: Gene Cloning, Functional Analysis, and Breeding Applications

This review provides a comprehensive overview of the current understanding of rice resistance to the brown planthopper (BPH), a major pest that poses significant threats to rice production through direct feeding damage and by transmitting viruses such as Rice grassy stunt virus (RGSV) and Rice ragged stunt virus (RRSV). We highlight the emergence of various BPH biotypes that have overcome specific resistance genes in rice. Advances in genetic mapping and cloning have identified 17 BPH resistance genes, classified into typical R genes encoding nucleotide-binding leucine-rich repeat (NLR) proteins and atypical R genes such as lectin receptor kinases and proteins affecting cell wall composition. The molecular mechanisms of these genes involve the activation of plant defense pathways mediated by phytohormones like jasmonic acid (JA), salicylic acid (SA), and ethylene, as well as the production of defensive metabolites. We also examine the complex interactions between BPH salivary proteins and rice defense responses, noting how salivary effectors can both suppress and trigger plant immunity. The development and improvement of BPH-resistant rice varieties through conventional breeding and molecular marker-assisted selection are discussed, including strategies like gene pyramiding to enhance resistance durability. Finally, we outline the challenges and future directions in breeding for durable BPH resistance, emphasizing the need for continued research on resistance mechanisms and the development of rice varieties with broad-spectrum and long-lasting resistance.

Biodegradation of imidacloprid and diuron by Simplicillium sp. QHSH-33

Imidacloprid (IMI) and diuron (DIU) are widely used pesticides in agricultural production. However, their excessive use and high residues have caused harm to the ecological environment and human health. Microbial remediation as an efficient and low-toxic method has become a research hotspot for controlling environmental pollutants. A fungus QHSH-33, identified as Simplicillium sp., has the ability to degrade neonicotinoids IMI and phenylurea DIU. When QHSH-33 and pesticide were co-cultured in liquid medium for 7 days, the degradation rates of IMI and DIU by QHSH-33 in simulated field soil microenvironment were 50.19 % and 70.57 %, respectively. Through HPLC-MS analysis, it was found that the degradation of IMI mainly involved nitro reduction, hydroxylation and other reactions. Three degradation pathways and eight degradation products were identified, among which two metabolites were obtained by microbial transformation of IMI for the first time. The degradation of DIU mainly involved demethylation and dehalogenation reactions, and two degradation pathways and four degradation products were identified, one of which was a new degradation product of DIU. Toxicity assessment demonstrated that most of the degradation products might be considerably less harmful than IMI and DIU. Whole genome sequencing of QHSH-33 revealed a genome size of 33.2 Mbp with 11,707 genes. The genome of QHSH-33 was annotated by KEGG to reveal 128 genes related to exogenous degradation and metabolism. After local blast with reported IMI and DIU degrading enzymes, seven IMI-degrading related genes and seven DIU-degrading related genes were identified in the QHSH-33 genome. The results of this study will help to expand our knowledge on the microbial decomposition metabolism of IMI and DIU, and provide new insights into the degradation mechanism of IMI and DIU in soil and pure culture system, laying a foundation for QHSH-33 strain applied to the removal, biotransformation or detoxification of IMI and DIU.

Expressional respones of hsp70 genes against abiotic and entomopathgenic stresses in four different noctuid larval species (Lepidoptera: Noctidae)

Heat shock proteins (Hsps) are stress response proteins. In a previous study, host larval Hsp70s were identified as the structural proteins of virions of Heliothis virescens ascovirus 3h (HvAV-3h), an insect virus that mainly infects noctuid larvae. To investigate the response of hsp70s of healthy Mythimna separata, Spodoptera exigua, Spodoptera frugiperda, and Spodoptera litura larvae to various abiotic or entomopathogenic stresses, quantitative PCR was used to detect larval hsp70s expression patterns. Results showed distinct expression patterns of hsp70s in response to different abiotic stresses. Notably, Mshsp70 expression pattern resembled Slhsp70 under most treatments. In healthy larvae, no tissue tropism was observed concerning the relative expression of Mshsp70, Sfhsp70, and Slhsp70. After infection with HvAV-3h, the expression of hsp70s in all dissected tissues of all tested larval species increased. Significant differences were found in the fat bodies of M. separata, S. exigua, and S. litura as well as in the hemolymph of S. exigua and S. litura. Subsequent silencing of Slhsp70, resulted in a significant decrease in DNA replication levels of HvAV-3h in S. litura larvae at 24 and 72 h post RNA interference, indicating that Slhsp70 is necessary for DNA replication in HvAV-3h. These data can provide references for the studying on the stress response of noctuid larvae to different environmental factors.

Latest Review Papers in Molecular Plant Sciences 2023

Success in sustaining food security in the face of global climate change depends on the multi-disciplinary efforts of plant science, physics, mathematics, and computer sciences, whereby each discipline contributes specific concepts, information, and tools [...].

Sublethal effects of chlorantraniliprole on immunity in Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae): Promote encapsulation by upregulating a heat shock protein 70 family gene SfHSP68.1

As an agricultural pest, the fall armyworm (FAW), Spodoptera frugiperda, poses a severe threat to agriculture in China. Chlorantraniliprole has been widely used to control this pest. In our previous studies, we discovered that LD10, LD20, and LD30 chlorantraniliprole promoted encapsulation in the 4th instar larvae of the FAW, with LD30 chlorantraniliprole having the most significant effect. To further investigate the molecular mechanism underlying the sublethal effects of chlorantraniliprole on encapsulation in the FAW, this study conducted the effects of encapsulation in 4th instar larvae of the FAW exposed to LD30 chlorantraniliprole. Then, we analyzed the transcriptome of the FAW hemolymph treated with LD30 chlorantraniliprole and identified genes related to encapsulation using RNAi. Our results showed that the encapsulation in the FAW was enhanced at 6, 12, 18, 24, and 48 h after exposure to LD30 chlorantraniliprole. Additionally, LD30 chlorantraniliprole significantly affected the expression of certain immune-related genes, with the heat shock protein 70 family gene SfHSP68.1 showing the most significant upregulation. Subsequent interference with SfHSP68.1 resulted in a significant inhibition of encapsulation in FAW. These findings suggested that LD30 chlorantraniliprole can promote encapsulation in the FAW by upregulating SfHSP68.1 expression. This study provides valuable insights into the sublethal effects of chlorantraniliprole on encapsulation in the FAW and the interaction between encapsulation and heat shock proteins (HSPs).

Molecular and functional characterization of heat-shock protein 70 in Aphis gossypii under thermal and xenobiotic stresses

Aphis gossypii, a globally distributed and economically significant pest of several crops, is known to infest a wide range of host plants. Heat shock proteins (Hsps), acting as molecular chaperones, are essential for the insect's environmental stress responses. The present study investigated the molecular characteristics and expression patterns of AgHsp70, a heat shock protein gene, in Aphis gossypii. Our phylogenetic analysis revealed that AgHsp70 shared high similarity with homologs from other insects, suggesting a conserved function across species. The developmental expression profiles of AgHsp70 in A. gossypii showed that the highest transcript levels were observed in the fourth instar nymphs, while the lowest levels were detected in the third instar nymphs. Heat stress and exposure to four different xenobiotics (2-tridecanone, tannic acid, gossypol, and flupyradifurone (4-[(2,2-difluoroethyl)amino]-2(5H)-furanone)) significantly up-regulated AgHsp70 expression. Knockdown of AgHsp70 using RNAi obviously increased the susceptibility of cotton aphids to 2-tridecanone, gossypol and flupyradifurone. Dual-luciferase reporter assays revealed that gossypol and flupyradifurone significantly enhanced the promoter activity of AgHsp70 at a concentration of 10 mg/L. Furthermore, we identified the transcription factor heat shock factor (HSF) as a regulator of AgHsp70, as silencing AgHSF reduced AgHsp70 expression. Our results shed light on the role of AgHsp70 in xenobiotic adaptation and thermo-tolerance.

RNA Interference-Screening of Potentially Lethal Gene Targets in the White-Backed Planthopper Sogatella furcifera via a Spray-Induced and Nanocarrier-Delivered Gene Silencing System

RNA interference (RNAi) is a widespread post-transcriptional silencing mechanism that targets homologous mRNA sequences for specific degradation. An RNAi-based pest management strategy is target-specific and considered a sustainable biopesticide. However, the specific genes targeted and the efficiency of the delivery methods can vary widely across species. In this study, a spray-induced and nanocarrier-delivered gene silencing (SI-NDGS) system that incorporated gene-specific dsRNAs targeting conserved genes was used to evaluate phenotypic effects in white-backed planthopper (WBPH). At 2 days postspraying, transcript levels for all target genes were significantly reduced and knockdown of two gene orthologs, hsc70-3 and PP-α, resulted in an elevated mortality (>60%) and impaired ecdysis. These results highlight the utility of the SI-NDGS system for identifying genes involved in WBPH growth and development that could be potentially exploitable as high mortality target genes to develop an alternative method for WBPH control.

Chromosome-level genome of the poultry shaft louse Menopon gallinae provides insight into the host-switching and adaptive evolution of parasitic lice

BACKGROUND

Lice (Psocodea: Phthiraptera) are one important group of parasites that infects birds and mammals. It is believed that the ancestor of parasitic lice originated on the ancient avian host, and ancient mammals acquired these parasites via host-switching from birds. Here we present the first chromosome-level genome of Menopon gallinae in Amblycera (earliest diverging lineage of parasitic lice). We explore the transition of louse host-switching from birds to mammals at the genomic level by identifying numerous idiosyncratic genomic variations.

RESULTS

The assembled genome is 155 Mb in length, with a contig N50 of 27.42 Mb. Hi-C scaffolding assigned 97% of the bases to 5 chromosomes. The genome of M. gallinae retains a basal insect repertoire of 11,950 protein-coding genes. By comparing the genomes of lice to those of multiple representative insects in other orders, we discovered that gene families of digestion, detoxification, and immunity-related are generally conserved between bird lice and mammal lice, while mammal lice have undergone a significant reduction in genes related to chemosensory systems and temperature. This suggests that mammal lice have lost some of these genes through the adaption to environment and temperatures after host-switching. Furthermore, 7 genes related to hematophagy were positively selected in mammal lice, suggesting their involvement in the hematophagous behavior.

CONCLUSIONS

Our high-quality genome of M. gallinae provides a valuable resource for comparative genomic research in Phthiraptera and facilitates further studies on adaptive evolution of host-switching within parasitic lice.

Unveiling the role of bZIP transcription factors CREB and CEBP in detoxification metabolism of Nilaparvata lugens (Stål)

The basic leucine zipper (bZIP) superfamily is a crucial group of xenobiotics in insects. However, little is known about the function of CAAT enhancer binding proteins (CEBP) and cAMP response element binding protein (CREB) in Nilaparvata lugens. In the present study, NlCEBP and NlCREB were cloned and identified. Quantitative polymerase real-time chain reaction (qRT-PCR) analysis showed the expression of NlCEBP and NlCREB was significantly induced after chemical insecticides exposure. Silencing of NlCEBP and NlCREB increased the susceptibility of N. lugens to insecticides, and the detoxification enzyme activities were also significantly decreased. In addition, comparative transcriptome analysis revealed that 174 genes were significantly co-down-regulated after interfering with the two transcription factors. GO analysis showed that co-down-regulated genes are mostly related to energy transport and metabolic functions indicating the potential regulatory role of NlCEBP and NlCREB in detoxification metabolism. Our research shed lights on the functional roles of transcription factors NlCEBP and NlCREB in the detoxification metabolism of N. lugens, providing a theoretical basis for pest management and comprehensive control of this pest and increasing our understanding of insect toxicology.

Recent Advances in the Genetic and Biochemical Mechanisms of Rice Resistance to Brown Planthoppers (Nilaparvata lugens Stål)

Rice (Oryza sativa L.) is the staple food of more than half of Earth's population. Brown planthopper (Nilaparvata lugens Stål, BPH) is a host-specific pest of rice responsible for inducing major losses in rice production. Utilizing host resistance to control N. lugens is considered to be the most cost-effective method. Therefore, the exploration of resistance genes and resistance mechanisms has become the focus of breeders' attention. During the long-term co-evolution process, rice has evolved multiple mechanisms to defend against BPH infection, and BPHs have evolved various mechanisms to overcome the defenses of rice plants. More than 49 BPH-resistance genes/QTLs have been reported to date, and the responses of rice to BPH feeding activity involve various processes, including MAPK activation, plant hormone production, Ca2+ flux, etc. Several secretory proteins of BPHs have been identified and are involved in activating or suppressing a series of defense responses in rice. Here, we review some recent advances in our understanding of rice-BPH interactions. We also discuss research progress in controlling methods of brown planthoppers, including cultural management, trap cropping, and biological control. These studies contribute to the establishment of green integrated management systems for brown planthoppers.

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.

Recent Advances in Molecular Mechanism and Breeding Utilization of Brown Planthopper Resistance Genes in Rice: An Integrated Review

Over half of the world's population relies on rice as their staple food. The brown planthopper (Nilaparvata lugens Stål, BPH) is a significant insect pest that leads to global reductions in rice yields. Breeding rice varieties that are resistant to BPH has been acknowledged as the most cost-effective and efficient strategy to mitigate BPH infestation. Consequently, the exploration of BPH-resistant genes in rice and the development of resistant rice varieties have become focal points of interest and research for breeders. In this review, we summarized the latest advancements in the localization, cloning, molecular mechanisms, and breeding of BPH-resistant rice. Currently, a total of 70 BPH-resistant gene loci have been identified in rice, 64 out of 70 genes/QTLs were mapped on chromosomes 1, 2, 3, 4, 6, 8, 10, 11, and 12, respectively, with 17 of them successfully cloned. These genes primarily encode five types of proteins: lectin receptor kinase (LecRK), coiled-coil-nucleotide-binding-leucine-rich repeat (CC-NB-LRR), B3-DNA binding domain, leucine-rich repeat domain (LRD), and short consensus repeat (SCR). Through mediating plant hormone signaling, calcium ion signaling, protein kinase cascade activation of cell proliferation, transcription factors, and miRNA signaling pathways, these genes induce the deposition of callose and cell wall thickening in rice tissues, ultimately leading to the inhibition of BPH feeding and the formation of resistance mechanisms against BPH damage. Furthermore, we discussed the applications of these resistance genes in the genetic improvement and breeding of rice. Functional studies of these insect-resistant genes and the elucidation of their network mechanisms establish a strong theoretical foundation for investigating the interaction between rice and BPH. Furthermore, they provide ample genetic resources and technical support for achieving sustainable BPH control and developing innovative insect resistance strategies.

Insights into the ubiquity, persistence and microbial intervention of imidacloprid

Imidacloprid, a neonicotinoid pesticide, is employed to increase crop productivity. Meanwhile, its indiscriminate application severely affects the non-target organisms and the environment. As an eco-friendly and economically workable option, the microbial intervention has garnered much attention. This review concisely outlines the toxicity, long-term environmental repercussions, degradation kinetics, biochemical pathways, and interplay of genes implicated in imidacloprid remediation. The studies have highlighted imidacloprid residue persistence in the environment for up to 3000 days. In view of high persistence, effective intervention is highly required. Bacteria-mediated degradation has been established as a viable approach with Bacillus spp. being among the most efficient at 30 ℃ and pH 7. Further, a comparative metagenomic investigation reveals dominant neonicotinoid degradation genes in agriculture compared to forest soils with distinctive microbial communities. Functional metabolism of carbohydrates, amino acids, fatty acids, and lipids demonstrated a significantly superior relative abundance in forest soil, implying its quality and fertility. The CPM, CYP4C71v2, CYP4C72, and CYP6AY3v2 genes that synthesize cyt p450 monooxygenase enzyme play a leading role in imidacloprid degradation. In the future, a systems biology approach incorporating integrated kinetics should be utilized to come up with innovative strategies for moderating the adverse effects of imidacloprid on the environment.

Study on the relationship of Hsp70 with the temperature sensitivity of pedunsaponin A poisoning Pomacea canaliculata

Previous studies have found that temperature influences molluscicidal the activity of pedunsaponin A (PA), which may be related to the expression of Hsp70, a cold-tolerance gene in Pomacea canaliculata. We determined the temperature effect of PA and the relationship between Hsp70 and temperature sensitivity of P. canaliculata poisoned by PA. Toxicity tests resulted in LC₅₀ values of 17.7239 mg⋅L^-1 at 10 °C, which decreased to 2.5774 mg⋅L^-1 at 30 °C, implying a positive correlation between toxicity of PA and temperature. After Hsp70 being interfered, the mortality rate of P. canaliculata treated with PA for 72 h was 70%, which was significantly higher than that of snails treated with PA for 72 h without interfering (56.7%). Meanwhile, immune enzyme activities such as SOD, ACP and AKP were significantly increased in the interfered group and expression level of PcAdv in the gill was also significantly increased. These results suggest that deletion of Hsp70 promotes the activation of some immune enzymes of P. canaliculata and elevates the content of target proteins to cope with the dual stresses of low temperatures and molluscicides. These findings indicate that the Hsp70 plays an important role in influencing the temperature sensitivity of P. canaliculata when treated with PA.

Molecular characterization of six heat shock protein 70 genes from Arma chinensis and their expression patterns in response to temperature stress

Arma chinensis is an important predatory enemy of many agricultural and forest pests. Heat shock protein 70 (Hsp70) plays an essential role in insect adaptation to various stress factors. To explore the functions of Hsp70s in relation to thermal tolerance of A. chinensis, full-length cDNAs of six Hsp70 genes (AcHsp70Ba, AcHsp70-4, AcHsp68a, AcHsp68b, AcHsp70-2, and AcHsc70-4) were cloned. Their open reading frames (ORFs) were 1902, 2454, 1884, 1905, 1872, and 1947 bp, respectively. Developmental expression profiles showed that AcHsp70Ba, AcHsp70-4, and AcHsc70-4 were extremely highly expressed in adult stages. AcHsp68a and AcHsp70-2 showed the highest level of expression in nymph stages, and AcHsp68b was mainly expressed in male adults. Tissue distribution analysis demonstrated that the AcHsp70s were ubiquitously expressed but showing gene-specific and sex-driven patterns of expression. High temperature induced the expression of the six AcHsp70s. Among them, AcHsp70Ba, AcHsp70-4, AcHsp68a, and AcHsc70-4 were significantly induced at 38 °C for 6 h, while all six AcHsp70s were significantly induced at 38 °C for 24 h. There were differences in responses of the six AcHsp70s to low-temperature stress. The expressions of AcHsp70-4, AcHsp68a, and AcHsp68b in male adults were significantly repressed at 4 °C for 6 h, whereas AcHsp70Ba and AcHsp70-2 were significantly induced. The levels of AcHsp70Ba, AcHsp68b, and AcHsp70-2 in female adults were significantly repressed at 4 °C for 24 h, whereas AcHsc70-4 was significantly induced. These results suggested that AcHsp70s play important roles in various developmental stages and tissue function, and contribute to the tolerance of A. chinensis to extreme temperatures.

The hsp70 new functions as a regulator of reproduction both female and male in Ophraella communa

Heat shock proteins (Hsps) function as molecular chaperones that enable organisms to withstand stress and maintain normal life activities. In this study, we identified heat shock protein 70 (encoded by hsp70), which exhibits a higher expression in the mature male testis than in the unmature testis of Ophraella communa. Tissue expression profile revealed that Ochsp70 levels in males were highest in the testis, whereas those in females were highest in the head. Moreover, the expression of Ochsp70 was found to be significantly induced in female bursa copulatrix after mating. Double-stranded RNA dsOchsp70 was injected into males to performance RNA interference, which significantly decreased the male Ochsp70 expression levels within 20 d post-injection, whereas no effect was observed on the Ochsp70 expression level in the females after mating with dsOchsp70-injected males. However, significant downregulation of female fertility was marked simultaneously. Furthermore, knockdown of female Ochsp70 expression also led to a significant reduction in fertility. Finally, comparative transcriptomic analysis identified glucose dehydrogenase and insulin-like growth factor binding protein as putative downstream targets of Ochsp70. Overall, we deduced that Ochsp70 is an indispensable gene and a potential male mating factor in O. communa, which regulates reproduction.

A heat shock 70kDa protein MaltHSP70-2 contributes to thermal resistance in Monochamus alternatus (Coleoptera: Cerambycidae): quantification, localization, and functional analysis

Background

Heat Shock Proteins 70 (HSP70s) in insects act on a diverse range of substrates to assist with overcoming extreme high temperatures. MaltHSP70-2, a member of HSP70s, has been characterized to involve in the thermotolerance of Monochamus alternatus in vitro, while quantification and localization of MaltHSP70-2 in various tissues and its functional analysis in vivo remain unclear.

Results

In this study, temporal expression of MaltHSP70-2 indicated a long-last inductive effect on MaltHSP70-2 expression maintained 48 hours after heat shock. MaltHSP70-2 showed a global response to heat exposure which occurring in various tissues of both males and females. Particularly in the reproductive tissues, we further performed the quantification and localization of MaltHSP70-2 protein using Western Blot and Immunohistochemistry, suggesting that enriched MaltHSP70-2 in the testis (specifically in the primary spermatocyte) must be indispensable to protect the reproductive activities (e.g., spermatogenesis) against high temperatures. Furthermore, silencing MaltHSP70-2 markedly influenced the expression of other HSP genes and thermotolerance of adults in bioassays, which implied a possible interaction of MaltHSP70-2 with other HSP genes and its role in thermal resistance of M. alternatus adults.

Conclusions

These findings shed new insights into thermo-resistant mechanism of M. alternatus to cope with global warming from the perspective of HSP70s functions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08858-1.

Induced heat shock protein 70 confers biological tolerance in UV-B stress-adapted Myzus persicae (Hemiptera)

As an environmental stress factor, ultraviolet-B (UV-B) radiation directly affects insect growth, development, and reproduction. Heat shock protein 70s kDa (Hsp70s) plays an important role in the environmental adaptation of insects. To determine the role of MpHsp70s in the UV-B tolerance of Myzus persicae (Sulzer), we identified the complete complementary DNA sequences of seven MpHsp70s. They were found to be ubiquitously expressed during different developmental stages and were highly expressed in second-instar nymphs and wingless adults. The expression levels of the MpHsp70s were significantly upregulated when exposed to different durations of UV-B stress. Nanocarrier-mediated dsMpHsp70 suppressed the expression of the MpHsp70s and reduced the body length, weight, survival rate, and fecundity of M. persicae under UV-B exposure. When the combinational RNAi approach was adopted, the effects on the survival rate and fecundity were greater under UV-B stress, except for MpHsc70-4. These results suggest that MpHsp70s are essential for the resistance of M. persicae to UV-B stress.

Transcriptomic modulation in response to an intoxication with deltamethrin in a population of Triatoma infestans with low resistance to pyrethroids

Background

Triatoma infestans is the main vector of Chagas disease in the Southern Cone. The resistance to pyrethroid insecticides developed by populations of this species impairs the effectiveness of vector control campaigns in wide regions of Argentina. The study of the global transcriptomic response to pyrethroid insecticides is important to deepen the knowledge about detoxification in triatomines.

Methodology and findings

We used RNA-Seq to explore the early transcriptomic response after intoxication with deltamethrin in a population of T. infestans which presents low resistance to pyrethroids. We were able to assemble a complete transcriptome of this vector and found evidence of differentially expressed genes belonging to diverse families such as chemosensory and odorant-binding proteins, ABC transporters and heat-shock proteins. Moreover, genes related to transcription and translation, energetic metabolism and cuticle rearrangements were also modulated. Finally, we characterized the repertoire of previously uncharacterized detoxification-related gene families in T. infestans and Rhodnius prolixus.

Conclusions and significance

Our work contributes to the understanding of the detoxification response in vectors of Chagas disease. Given the absence of an annotated genome from T. infestans, the analysis presented here constitutes a resource for molecular and physiological studies in this species. The results increase the knowledge on detoxification processes in vectors of Chagas disease, and provide relevant information to explore undescribed potential insecticide resistance mechanisms in populations of these insects.

Does Bacillus thuringiensis Affect the Stress and Immune Responses of Rhynchophorus ferrugineus Larvae, Females, and Males in the Same Way?

Simple Summary

Rhynchophorus ferrugineus is a destructive quarantine pest of palm trees, now widely distributed. Although broad-spectrum insecticides are often used to protect palm against R. ferrugineus, there is increasing concern about their effects on the environment and human health, especially where palm trees are located in urban areas. As an environmentally friendly entomopathogen, Bacillus thuringiensis (Bt) has been widely used to prevent other pest infestations. Although Bt products are the most sold bio-insecticides, there are still many interesting features to be investigated in the relationship of Bt and its hosts. We investigated the effect of Bt on larvae, females, and males. This research yielded experimental evidence of significant mortality and significant effects on immune system and stress answer. Within a few hours, stress due to Bt infection was detected in the hemocytes and in the brain providing better insights into the insect-pathogen interaction and highlighting the potential use of Bt in R. ferrugineus management.

Abstract

Bacillus thuringiensis (Bt) is considered a potentially useful entomopathogen against red palm weevil (RPW) Rhynchophorus ferrugineus. We compared the effects of Bt on mature larvae, females, and males. The pathogenicity of Bt was evaluated, estimating: Median Lethal Dose (LD₅₀), Median Lethal Time (LT₅₀), Total Hemocyte Count (THC), and Differential Hemocyte Counts (DHC), and the expression of the stress protein Heat Shock Protein 70 (Hsp 70) in hemocytes and the brain. Mortality exhibited a positive trend with the dosage and duration of exposure to Bt. Larvae were more susceptible than adults, and the LD₅₀ of females was almost double the value of that of the larvae. LT₅₀ value was higher for females than for males and larvae. Treatment with sub-lethal doses of Bt induced a decrease in THC in larvae, females, and males. In treated larvae, plasmatocytes decreased, while oenocytes and spherulocytes increased. In treated females, all types of hemocytes decreased, while in males the number of plasmatocytes decreased and granulocytes increased. We also registered the stress response directly on hemocytes showing that, already at 3 h after eating Bt, the expression of the stress protein Hsp 70 was modulated. This effect was also observed in brain tissue at 6 h after treatment. The results confirm that Bt treatment induces a pathogenic state in larvae and adults of both sexes, with effects after only a few hours from ingestion; however, the effects are different in magnitude and in type of target.

Characterization of Three Heat Shock Protein Genes in Pieris melete and Their Expression Patterns in Response to Temperature Stress and Pupal Diapause

Simple Summary

Pieris melete, a major pest of crucifers, undergoes obligatory diapause as pupae to survive unfavorable temperature extremes during hot summers and cold winters. Heat shock proteins 70 (Hsp70) participate in this process; however, little is known about the underlying changes in Hsp70 expression both during the summer and winter diapause. The study aimed to investigate expression patterns of Hsp70s (PmHsc70/PmHsp70a, b) in response to diapause and short-term temperature stresses. The results showed that the expression of PmHsc70 and PmHsp70b were upregulated both in summer and winter diapause. Heat shock significantly induced up-regulation of the three genes in both summer and winter diapause. In non-diapause pupae, none of the genes responded to cold or heat stress. Further, it was found that 39 °C for 30 min was the most sensitive heat stress condition for PmHsc70 expressions in summer diapause and all three genes’ expressions in winter diapause. During summer diapause, the expression of the genes was up-regulated in response to high temperature acclimation at 31 °C. Meanwhile, only PmHsp70a and PmHsp70b were up-regulated when acclimated to a low temperature of 4 °C in winter diapause. In conclusion, the current results indicate that PmHsp70s plays a crucial role during both summer and winter diapause, in response to temperature stresses; and our findings may contribute to the increasing knowledge on seasonal diapause adaption.

Abstract

Heat shock protein 70 genes participate in obligatory pupal diapause in Pieris melete to survive unfavorable conditions. In this study, three full-length cDNAs of PmHsc70, PmHsp70a and PmHsp70b were identified, and their expression patterns in response to diapause and short-term temperature stresses were investigated. Summer and winter diapause were induced in the pupae and non-diapause individuals were used as a control. The pupae from each diapause group were subjected to either hot or cold conditions and the expression levels of the HSP genes were measured. Our results showed that up-regulation of PmHsc70 and PmHsp70b were detected both in summer and winter diapause, but not for PmHsp70a. Under cold stress, PmHsp70a and PmHsp70b were upregulated in summer and winter diapause, while heat shock significantly induced upregulation of all three genes. In non-diapause pupae, none of the genes responded to cold or heat stress. Furthermore, we found that incubation at 39 °C for 30 min was the most sensitive heat stress condition for PmHsc70 expression in summer diapause. On the other hand, the same temperature was effective for PmHsc70, PmHsp70a, and PmHsp70b expression in winter diapause. During summer diapause, expression of all three genes was upregulated in response to high-temperature acclimation at 31 °C, but only PmHsp70a and PmHsp70b were upregulated when acclimated to a low temperature of 4 °C in winter diapause. These results suggest that the PmHsc70, PmHsp70a, and PmHsp70b respond differently to pupal diapause and temperature stress, and that PmHsc70 is more sensitive to heat shock than to cold stress.

Plant elicitor peptide signalling confers rice resistance to piercing-sucking insect herbivores and pathogens

Rice is a staple food crop worldwide, and its production is severely threatened by phloem-feeding insect herbivores, particularly the brown planthopper (BPH, Nilaparvata lugens), and destructive pathogens. Despite the identification of many BPH resistance genes, the molecular basis of rice resistance to BPH remains largely unclear. Here, we report that the plant elicitor peptide (Pep) signalling confers rice resistance to BPH. Both rice PEP RECEPTORs (PEPRs) and PRECURSORs of PEP (PROPEPs), particularly OsPROPEP3, were transcriptionally induced in leaf sheaths upon BPH infestation. Knockout of OsPEPRs impaired rice resistance to BPH, whereas exogenous application of OsPep3 improved the resistance. Hormone measurement and co-profiling of transcriptomics and metabolomics in OsPep3-treated rice leaf sheaths suggested potential contributions of jasmonic acid biosynthesis, lipid metabolism and phenylpropanoid metabolism to OsPep3-induced rice immunity. Moreover, OsPep3 elicitation also strengthened rice resistance to the fungal pathogen Magnaporthe oryzae and bacterial pathogen Xanthamonas oryzae pv. oryzae and provoked immune responses in wheat. Collectively, this work demonstrates a previously unappreciated importance of the Pep signalling in plants for combating piercing-sucking insect herbivores and promises exogenous application of OsPep3 as an eco-friendly immune stimulator in agriculture for crop protection against a broad spectrum of insect pests and pathogens.

Heat Shock 70 kDa Protein Cognate 3 of Brown Planthopper Is Required for Survival and Suppresses Immune Response in Plants

The brown planthopper (Nilaparvata lugens) is a monophagous pest of rice (Oryza sativa), which threatens food security around the world. Insect Heat shock proteins 70 kDa (Hsp70s) play a key role in insect growth and development, however, if they also modulate the plant physiological processes is still unclear. In this study, we identified the Heat shock 70 kDa protein cognate 3 (NlHSC70-3) of BPH from compared protein profiles of Nipponbare tissues after BPH infestation via LC/MS. NlHSC70-3 has a predicted signal peptide and displays high transcription levels in the salivary glands, which further supported that it is secreted into plants by BPH during the feeding process. Using RNA interference (RNAi), we showed that NlHSC70-3 is indispensable for the survival of BPH on rice. Most importantly, NlHSC70-3 mediates the plant immune responses including cell death, flg22-induced ROS burst and defense-related gene expression in N. benthamiana. These results demonstrate that NlHSC70-3 may function as an effector manipulating plant physiological processes to facilitate pest survival on rice, which provides a new potential target for future pest control.

Integrative Analysis of lncRNA-mRNA Co-expression Provides Novel Insights Into the Regulation of Developmental Transitions in Female Varroa destructor

Varroa destructor is a major pathogenic driver of the Western honeybee colony losses globally. Understanding the developmental regulation of V. destructor is critical to develop effective control measures. Development is a complex biological process regulated by numerous genes and long non-coding RNAs (lncRNAs); however, the underlying regulation of lncRNAs in the development of V. destructor remains unknown. In this study, we analyzed the RNA sequencing (RNA-Seq) data derived from the four stages of female V. destructor in the reproductive phase (i.e., egg, protonymph, deutonymph, and adult). The identified differentially expressed mRNAs and lncRNAs exhibited a stage-specific pattern during developmental transitions. Further functional enrichment established that fat digestion and absorption, ATP-binding cassette (ABC) transporters, mitogen-activated protein kinase (MAPK) signaling pathway, and ubiquitin-proteasome pathway play key roles in the maturation of female V. destructor. Moreover, the lncRNAs and mRNAs of some pivotal genes were significantly upregulated at the deutonymph stage, such as cuticle protein 65/6.4/63/38 and mucin 5AC, suggesting that deutonymph is the key stage of metamorphosis development and pathogen resistance acquisition for female V. destructor. Our study provides novel insights into a foundational understanding of V. destructor biology.

A heat shock protein protects against oxidative stress induced by lambda-cyhalothrin in the green peach aphid Myzus persicae

Lambda-cyhalothrin (LCT) is a pyrethroid insecticide widely used to control insect pests. Insect exposure to LCT may cause abnormal accumulation of reactive oxygen species (ROS) and result in oxidative damage. Heat shock proteins (HSPs) may help protect against oxidative stress. However, little is known about the role of HSPs in response to LCT in the green peach aphid, Myzus persicae. This insect is an important agricultural pest causing severe yield losses in crops. In this study, we characterized a cDNA sequence (MpHsp70) encoding a member of the HSP70 family in M. persicae. MpHsp70 encoded a 623 amino acid protein putatively localized in the cytosol. The highest expression level of MpHsp70 occurred in fourth-instar nymphs. Treatment of M. persicae with LCT resulted in oxidative stress and significantly increased H₂O₂ and malondialdehyde levels. This led to an elevated transcription level of MpHsp70. Injection of H₂O₂ into M. persicae also upregulated the MpHsp70 expression level, suggesting that MpHsp70 is responsive to ROS, particularly H₂O₂, induced by LCT. Recombinant MpHSP70 protein was expressed in Escherichia coli. E. coli cells overexpressing MpHSP70 exhibited significant tolerance to H₂O₂ and the ROS generators, cumene hydroperoxide and paraquat. This indicated that MpHSP70 protects against oxidative stress. Furthermore, knockdown of MpHsp70 by RNA interference resulted in increased susceptibility in apterous adults of M. persicae to LCT. These findings indicate that MpHsp70 plays an important role in defense against LCT-induced oxidative stress and insecticide susceptibility in M. persicae.

Application of transcriptomic analysis to unveil the toxicity mechanisms of fall armyworm response after exposure to sublethal chlorantraniliprole

The anthranilic diamide insecticide chlorantraniliprole is highly effective against Lepidoptera pests, but the underlying mechanisms of toxic effects of chlorantraniliprole exposures for adapting to the chemical environment are poorly known in fall armyworm (FAW), Spodoptera frugiperda (J.E.Smith). FAW being one of the most pests of maize in Latin America, suddenly appeared in China in 2019 and spread rapidly. In this study, using bioassay and transcriptomic and biochemical analyses, we comprehensively investigated gene expression changes of third instar larvae in response to different sublethal concentrations (LC10 and LC30) of chlorantraniliprole in this insect. Exposure to LC10 chlorantraniliprole (0.73 mg/L) causes 1266 differentially expressed genes (DEGs), of which 578 are up-regulated and 688 down-regulated. Exposure to LC30 (2.49 mg/L) causes differential expression of 3637 DEGs (1545 up-, 2092 down-regulated). Interestingly, the LC30 treatment led to a significant increase in the number of DEGs compared to that of the LC10, indicating a concentration effect manner. Moreover, enrichment analysis identified important DEGs belonging to specific categories, such as amino acid, carbohydrate, lipid, energy, xenobiotics metabolisms, signal transduction, and posttranslational modification pathways, and enzymes activities in enriched pathways were significantly altered at the LC10 and LC30, which matched transcriptome analysis to mediate toxic mechanisms. The DEGs encoding detoxification-related genes were identified and validated by quantitative real-time PCR (qRT-PCR), which correlated with the RNA-sequencing (RNA-seq) data. To our knowledge, these findings provide the first toxicity mechanisms for a better understanding of chlorantraniliprole action and detoxification in FAW and other insect pests at molecular level.

Isolation of two new genes encoding heat shock protein 70 in Bemisia tabaci and analysis during thermal stress

The heat shock protein 70 family (HSP70) is among the most varied HSP family with respect to structure and function. The phloem-feeding insect Bemisia tabaci (Gennadius) is an important pest of cotton, vegetables and ornamentals that transmits several plant viruses and causes enormous agricultural losses. In this study, two new HSP70 genes (Bthsp70-2 and Bthsp70-3) were isolated from the MED cryptic species B. tabaci, an important phloem-feeding pest of vegetables and ornamentals. Bthsp70-2 and Bthsp70-3 encoded proteins comprised of 652 and 676 amino acids, and the deduced proteins were closely related to other HSP70s in Hemiptera. Expression analyses using real-time quantitative PCR indicated that Bthsp70-2 and Bthsp70-3 were induced in B. tabaci pupae and adults during high and low thermal stress. Bthsp70-2 and Bthsp70-3 exhibited similar, but not identical, expression patterns when exposed to different durations of high temperature stress. Oral ingestion of dsBthsp70 reduced the expression level of Bthsp70-2 and Bthsp70-3 in B. tabaci and increased the mortality of B. tabaci during heat shock. In conclusion, Bthsp70-2 and Bthsp70-3 exhibit different expression patterns during thermal stress, thus expanding the roles of HSPs in B. tabaci.

Characterization, and Functional Analysis of Hsp70 and Hsp90 Gene Families in Glyphodes pyloalis Walker (Lepidoptera: Pyralidae)

Glyphodes pyloalis Walker (Lepidoptera: Pyralidae) is a destructive mulberry pest, causing great damage to mulberry in China. Heat shock proteins (Hsps) are involved in various signal pathways and regulate lots of physiological processes in insects. The function of Hsps in G. pyloalis, however, has still received less attention. Here, we identified five Hsp genes from G. pyloalis transcriptome dataset including two Hsp70 family genes (GpHsp71.3 and GpHsp74.9) and three Hsp90 family genes (GpHsp82.4, GpHsp89, and GpHsp93.4). Quantitative Real-time PCR validation revealed that all Hsps of G. pyloalis have significant expression in pupal and diapause stage, at which the larvae arrest the development. Expressions of GpHsp71.3 and GpHsp82.4 were increased significantly after thermal treatment at 40°C, and this upregulation depended on heat treatment duration. Furthermore, silencing GpHsp82.4 by RNA interference led to a significant increase in mortality of G. pyloalis larvae under the heat stress compared to the control group. After starvation stress, the expression levels of GpHsp82.4 and GpHsp93.4 were significantly increased. At last, after being parasitized by the parasitoid wasp Aulacocentrum confusum, Hsp70 and Hsp90 genes of G. pyloalis were decreased significantly in the early stage of parasitization and this moderation was affected by time post-parasitization. This study highlights the function of G. pyloalis Hsps in response to environmental stress and provides a perspective for the control of this pest.

Heat Shock Protein 70 Family in Response to Multiple Abiotic Stresses in the Silkworm

Simple Summary

Heat shock protein 70 family is widely distributed in all the organisms, which plays important roles in protein folding and preventing protein denaturation. Heat or cold stress response has been studied in some insects, but there is a lack of systematic investigation on the response of the same species to multiple stressors. Here, we performed genome-wide identification of heat shock protein 70 family in the silkworm, Bombyx mori. Using the silkworm as a model, the transcription profiles of all the genes against heat, cold, and pesticides were studied. Our findings would provide insights into the functional diversification of heat shock proteins 70 in insects.

Abstract

The 70 kDa heat shock proteins play important roles in protecting organisms against environmental stresses, which are divided into stress-inducible forms (HSP70s) and heat shock cognates (HSC70s). In this study, heat shock protein 70 family was identified in the whole genome of the silkworm. Based on the known nomenclature and phylogenetic analysis, four HSP70s and five HSC70s were classified. Relatively, heat shock cognates were more conservative and were constitutively expressed in various tissues of the silkworm larvae. Under thermal (37 °C and 42 °C) and cold (2 °C) stresses, the expressions of HSP70–1, HSP70–2, and HSP70–3 were up-regulated, and the highest induction reached 4147.3, 607.1, and 1987.3 times, respectively. Interestingly, HSC70–1, HSC70–4, and HSC70–5 also showed slight induced expressions in the fat body and/or midgut under thermal stresses. In addition, the expression of HSP70–1 was induced by dichlorvos and phoxim insecticides, while most HSC70 genes were inhibited. The results suggested that stress-inducible forms play more important roles in adaptation to various stresses than HSC70s.

Chromosome-level genome assembly of the mirid predator Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae), an important natural enemy in the rice ecosystem

Though the genomes of many rice herbivorous pests have recently been well characterized, little is known about the genome of their natural enemies. Here, by using the Illumina and PacBio platforms, we sequenced and assembled the whole genome of the mirid species Cyrtorhinus lividipennis Reuter (Hemiptera: Miridae), which is an economically and ecologically important natural enemy in the rice ecosystem acting as a dominant predator for planthoppers and leafhoppers in the field. Through Hi-C scaffolding, 1615 scaffolds with a total size of 338.08 Mb were successfully anchored onto 13 chromosomes. The assembled genome size was 345.75 Mb with a final scaffold N50 of 27.58 Mb. Approximately 107.51 Mb of sequences accounting for 31.10% of the genome were identified as repeat elements, and 14,644 protein-coding genes were annotated. Phylogenetic analysis showed that C. lividipennis clustered with other Hemipteran species and diverged from Apolygus lucorum about 66.7 million years ago. Gene families related to detoxification, environmental adaptation and digestion were analysed comparatively with other Hemipteran species, but no significant expansion or contraction was found in C. lividipennis. We also observed male meiosis in C. lividipennis, which showed a typical post-reduction of sex chromosomes and a karyotype of 2n = 22 + XY. As the first natural-enemy genome in the rice ecosystem, the genomic resource of C. lividipennis not only expands our understanding of the multitrophic interactions (host plant-prey-predator), but also provides a genomic basis for better understanding this dominant predator and therefore promotes sustainable rice pest management and food grain production.

Involvement of small heat shock proteins (sHsps) in developmental stages of fall armyworm, Spodoptera frugiperda and its expression pattern under abiotic stress condition

Fall armyworm (FAW), Spodoptera frugiperda a recent invasive pest in India is reported to cause significant damage by feeding voraciously on maize and other economic crops from tropical to temperate provinces. It is becoming an arduous challenge to control the pest as it can survive in a wide range of temperature conditions and is already said to develop resistance towards certain insecticides. The small Heat shock proteins (hereafter, sHsps) are known to play an important role in adaptation of insects under such stress conditions. Our present study involved characterization of the three sHsps genes (sHsp19.74, sHsp20.7 and sHsp19.07) which encoded proteins of about 175, 176 and 165 amino acids with a conserved α-crystalline domain. Phylogenetic analysis of deduced amino acid sequences of the three genes showed strong similarity with the other lepidopteran sHsps. The effect of different growth stages on the expression profile of these stress proteins has also been studied and the Quantitative real time PCR (qRT-PCR) analysis revealed that the transcript level of sHsp19.07 and sHsp20.7 were significantly upregulated under extreme heat (44 °C) and cold (5 °C) stress. However, sHsp19.74 responded only to heat treatment but not to the cold treatment. In addition, the expression profile of all three sHsps was significantly lower in the larval stage (5^th instar). Chlorantraniliprole treatment resulted in maximum expression of sHsp19.07 and sHsp20.7 after 12hr of exposure to the insecticide. Meanwhile, the same expression was observed after 8hr of exposure in case of sHsp19.74. These results proved that the sHsp genes of S. frugiperda were induced and modulated in response to abiotic stress, thus influencing the physiological function leading to survival of FAW in diversified climate in India.

HSP70/DNAJ Family of Genes in the Brown Planthopper, Nilaparvata lugens: Diversity and Function

Heat shock 70kDa proteins (HSP70s) and their cochaperones DNAJs are ubiquitous molecular chaperones, which function as the “HSP70/DNAJ machinery” in a myriad of biological processes. At present, a number of HSP70s have been classified in many species, but studies on DNAJs, especially in insects, are lacking. Here, we first systematically identified and characterized the HSP70 and DNAJ family members in the brown planthopper (BPH), Nilaparvata lugens, a destructive rice pest in Asia. A total of nine HSP70 and 31 DNAJ genes were identified in the BPH genome. Sequence and phylogenetic analyses revealed the high diversity of the NlDNAJ family. Additionally, spatio-temporal expression analysis showed that most NlHSP70 and NlDNAJ genes were highly expressed in the adult stage and gonads. Furthermore, RNA interference (RNAi) revealed that seven NlHSP70s and 10 NlDNAJs play indispensable roles in the nymphal development, oogenesis, and female fertility of N. lugens under physiological growth conditions; in addition, one HSP70 (NlHSP68) was found to be important in the thermal tolerance of eggs. Together, our results in this study shed more light on the biological roles of HSP70/DNAJ in regulating life cycle, coping with environmental stresses, and mediating the interactions within, or between, the two gene families in insects.

Sustaining induced heat shock protein 70 confers biological thermotolerance in a high-temperature adapted predatory mite Neoseiulus barkeri (Hughes)

BACKGROUND

In fluctuating climatic environments, heat acclimation in predatory mites is a superior adaptation strategy for effective agricultural pest management and can be used to enhance the abilities critical in biological control efficiency. We investigated the regulatory mechanism governing the remarkable plastic response of thermotolerance in a high-temperature adapted strain (HTAS) and discerned the differences in the defensive reactions between the HTAS and the conventional strain (CS) in the predatory mite Neoseiulus barkeri.

RESULTS

At 42 °C, the relative expression levels of four identified HSP70 genes increased rapidly in both N. barkeri strains; meanwhile the expression of NbHSP70-1 and NbHSP70-2 in CS sharply decreased after 4 h, displaying a distinct contrast with the remaining elevated expression in HTAS. Western blot analysis showed that the protein level of NbHSP70-1 in CS was dramatically elevated at 0.5 h and decreased at 6 h at 42 °C. Conversely, in HTAS, NbHSP70-1 was constantly induced and peaked at 6 h at 42 °C. Furthermore, HSP70 suppression by RNAi knockdown had a greater influence on the survival of HTAS, causing a higher mortality under high temperature than CS. Finally, the recombinant exogenous NbHSP70-1 protein enhanced the viability of E. coli BL21 under a lethal temperature of 50 °C.

CONCLUSION

Sustained accumulation of HSP70 proteins results in predatory phytoseiid mites with the thermotolerance advantage that could promote their biological control function to pests. The divergent constitutive regulation of HSP70 to a thermal environment is conducive to the flexible adaptability of predators in the higher trophic level to trade off under extremely adversity stress.

Inhibition of hepatocyte nuclear factor 4 confers imidacloprid resistance in Nilaparvata lugens via the activation of cytochrome P450 and UDP-glycosyltransferase genes

Increasing evidence indicates that insect resistance to synthesized insecticides is regulated by the nuclear receptors. However, the underlying mechanisms of this regulation are not clear. Here, we demonstrate that inhibition of hepatocyte nuclear factor 4 (HNF4) confers imidacloprid resistance in the brown planthopper (BPH) Nilaparvata lugens by regulating cytochrome P450 and UDP-glycosyltransferase (UGT) genes. An imidacloprid-resistant strain (Res) exhibited a 251.69-fold resistance to imidacloprid in comparison to the susceptible counterpart (Sus) was obtained by successive selection with imidacloprid. The expression level of HNF4 in the Res strain was lower than that in Sus, and knockdown of HNF4 by RNA interference significantly enhanced the resistance of BPH to imidacloprid. Comparative transcriptomic analysis identified 1400 differentially expressed genes (DEGs) in the HNF4-silenced BPHs compared to controls. Functional enrichment analysis showed that cytochrome P450- and UGT-mediated metabolic detoxification pathways were enriched by the up-regulated DEGs after HNF4 knockdown. Among of them, UGT-1-7, UGT-2B10 and CYP6ER1 were found to be over-expressed in the Res strain, and knockdown of either gene significantly decreased the resistance of BPH to imidacloprid. This study increases our understanding of molecular mechanisms involved in the regulation of insecticide resistance and also provides potential targets for pest management.

Adipokinetic hormone enhances CarE-mediated chlorpyrifos resistance in the brown planthopper, Nilaparvata lugens

Adipokinetic hormone (AKH), the principal stress-responsive neurohormone in insects, has been implicated in insect responses to insecticides. However, the functionality of AKH and its mode of signalling in insecticide resistance are unknown. Herein, we demonstrated that the enhanced activity of carboxylesterases (CarEs) is involved in the chlorpyrifos resistance in Nilaparvata lugens [brown planthopper (BPH)]. Chlorpyrifos exposure significantly induced the expression of AKH and its receptor AKHR in the susceptible BPH (Sus), and these two AKH signalling genes were over-expressed in the chlorpyrifos-resistant strain (Res) compared to Sus. RNA interference (RNAi) against AKH or AKHR decreased the CarE activity and suppressed the BPH's resistance to chlorpyrifos in Res. Conversely, AKH peptide injection elevated the CarE activity and enhanced the BPH's survival against chlorpyrifos in Sus. Furthermore, five CarE genes were identified to be positively affected by the AKH pathway using RNAi and AKH injection. Among these CarE genes, CarE and Esterase E4-1 were found to be over-expressed in Res compared to Sus, and knockdown of either gene decreased the BPH's resistance to chlorpyrifos. In conclusion, AKH plays a role in enhancing chlorpyrifos resistance in the BPH through positive influence on the expression of CarE genes and CarE enzyme activity.

Antioxidant Enzymes and Heat Shock Protein Genes from Liposcelis bostrychophila Are Involved in Stress Defense upon Heat Shock

Simple Summary

Liposcelis bostrychophila is one of the most serious pests of stored commodities among the psocids. Controlling psocids mainly relies on chemical insecticides and heat stress. In fact, L. bostrychophila has developed high levels of resistance or tolerance to heat treatment in grain storage systems. In this study, we evaluated the changes in malondialdehyde (MDA) concentration after different high temperatures. The result showed that MDA is increased slightly overall, but a drastic increase is detected at 42.5 °C for exposure of different times. To further explore the principles of L. bostrychophila in response to heat stress, we tested the changes of superoxide dismutase (SOD), catalase (CAT), peroxidases (POD) and glutathione-S-transferases (GST) activities under different heat treatments and identified four inducible LbHsp70 genes and one LbHsp110 gene. Enzyme activities and transcript levels changed drastically after different heat treatments. These findings contribute to our understanding of the mechanism of L. bostrychophila responding to heat stress and provide baseline information for further understanding the excellent targets of L. bostrychophila.

Abstract

Psocids are a new risk for global food security and safety because they are significant worldwide pests of stored products. Among these psocids, Liposcelis bostrychophila has developed high levels of resistance or tolerance to heat treatment in grain storage systems, and thus has led to investigation of molecular mechanisms underlying heat tolerance in this pest. In this study, the time-related effects of thermal stress treatments at relatively high temperatures on the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidases (POD), glutathione-S-transferases (GST) and malondialdehyde (MDA), of L. bostrychophila were determined. Thermal stress resulted that L. bostrychophila had a significantly higher MDA concentration at 42.5 °C, which indicated that the heat stress increased lipid peroxidation (LPO) contents and oxidative stress in this psocid pest. Heat stress also resulted in significant elevation of SOD, CAT and GST activities but decreased POD activity. Our data indicates that different antioxidant enzymes contribute to defense mechanisms, counteracting oxidative damage in varying levels. POD play minor roles in scavenging deleterious LPO, while enhanced SOD, CAT and GST activities in response to thermal stress likely play a more important role against oxidative damage. Here, we firstly identified five LbHsps (four LbHsp70s and one LbHsp110) from psocids, and most of these LbHsps (except LbHsp70-1) are highly expressed at fourth instar nymph and adults, and LbHsp70-1 likely presents as a cognate form of HSP due to its non-significant changes of expression. Most LbHsp70s (except LbHsp70-4) are significantly induced at moderate high temperatures (<40 °C) and decreased at extreme high temperatures (40–45 °C), but LbHsp110-1 can be significantly induced at all high temperatures. Results of this study suggest that the LbHsp70s and LbHsp110 genes are involved in tolerance to thermal stress in L. bostrychophila, and antioxidant enzymes and heat shock proteins may be coordinately involved in the tolerance to thermal stress in psocids.

Adipokinetic hormone regulates cytochrome P450-mediated imidacloprid resistance in the brown planthopper, Nilaparvata lugens

Insect resistance to chemical insecticide is a global problem that presents an ongoing threat to sustainable agriculture. Although the increased production of detoxification enzymes has been frequently implicated in resistance development, the mechanisms employed by insecticide-resistant insects for overexpression of these genes remain elusive. Here we report that neuropeptide adipokinetic hormone (AKH) negatively regulates the expression of CYP6ER1 and CYP6AY1, two important cytochrome P450 monooxygenases (P450s) that confer resistance to neonicotinoid imidacloprid in the brown planthopper (BPH). Imidacloprid exposure suppresses AKH synthesis in the susceptible BPH, and AKH is inhibited in the imidacloprid-resistant strain. RNA interference (RNAi) and AKH peptide injection revealed that imidacloprid exposure inhibits the AKH signaling cascade and then provokes reactive oxygen species (ROS) burst. These in turn activate the transcription factors cap 'n' collar isoform-C (CncC) and muscle aponeurosis fibromatosis (MafK). RNAi and ROS scavenger assays showed that ROS induces CYP6ER1 expression by activating CncC and MafK, while ROS mediates induction of CYP6AY1 through another unidentified pathway in the resistant BPH. Collectively, these results provide new insights into the regulation of insecticide resistance and implicate both the neuropeptide AKH-mediated ROS burst and transcription factors are involved in the overexpression of P450 detoxification genes in insecticide-resistant insects.

Insights into the Toxicity and Degradation Mechanisms of Imidacloprid Via Physicochemical and Microbial Approaches

Imidacloprid is a neonicotinoid insecticide that has been widely used to control insect pests in agricultural fields for decades. It shows insecticidal activity mainly by blocking the normal conduction of the central nervous system in insects. However, in recent years, imidacloprid has been reported to be an emerging contaminant in all parts of the world, and has different toxic effects on a variety of non-target organisms, including human beings, due to its large-scale use. Hence, the removal of imidacloprid from the ecosystem has received widespread attention. Different remediation approaches have been studied to eliminate imidacloprid residues from the environment, such as oxidation, hydrolysis, adsorption, ultrasound, illumination, and biodegradation. In nature, microbial degradation is one of the most important processes controlling the fate of and transformation from imidacloprid use, and from an environmental point of view, it is the most promising means, as it is the most effective, least hazardous, and most environmentally friendly. To date, several imidacloprid-degrading microbes, including Bacillus, Pseudoxanthomonas, Mycobacterium, Rhizobium, Rhodococcus, and Stenotrophomonas, have been characterized for biodegradation. In addition, previous studies have found that many insects and microorganisms have developed resistance genes to and degradation enzymes of imidacloprid. Furthermore, the metabolites and degradation pathways of imidacloprid have been reported. However, reviews of the toxicity and degradation mechanisms of imidacloprid are rare. In this review, the toxicity and degradation mechanisms of imidacloprid are summarized in order to provide a theoretical and practical basis for the remediation of imidacloprid-contaminated environments.

Induction of Heat Shock Protein Genes is the Hallmark of Egg Heat Tolerance in Agasicles hygrophila (Coleoptera: Chrysomelidae)

Insects are ecotothermic organisms. Their development, survival, reproduction as well as distribution and abundance are affected by temperature. Heat shock protein (HSP) gene expression is closely associated with temperature variation and influences the adaptation of organisms to adverse environments. The beetle Agasicles hygrophila has successfully been used for biological control of the invasive plant alligator weed (Alternanthera philoxeroides). As A. hygrophila populations are substantially inhibited by high temperatures in the summer, increasing global temperatures may limit the efficacy of this control agent. We previously established that A. hygrophila eggs have low tolerance to heat and this factored into the decreased numbers of A. hygrophila beetles at temperatures of 37.5°C and above. Here, we identified 26 HSP genes in A. hygrophila and examined the relationship between the transcript levels of these genes and heat tolerance. The temperature at which the expression of these 21 HSP genes peaked (Tpeak) was 37.5°C, which is in line with the limit of the high temperatures that A. hygrophila eggs tolerate. Therefore, we speculate that the Tpeak of HSP gene expression in eggs indicates the upper limit of temperatures that A. hygrophila eggs tolerate. This study identifies HSP genes as potential robust biomarkers and emphasizes that determining species' heat tolerance in their natural habitats remains an important consideration for biocontrol. HSP gene expression data provide information about a species' heat tolerance and may be used to predict its geographical distribution.

Insecticidal Activity of Artemisia vulgaris Essential Oil and Transcriptome Analysis of Tribolium castaneum in Response to Oil Exposure

Red flour beetle (Tribolium castaneum) is one of the most destructive pests of stored cereals worldwide. The essential oil (EO) of Artemisia vulgaris (mugwort) is known to be a strong toxicant that inhibits the growth, development, and reproduction of T. castaneum. However, the molecular mechanisms underlying the toxic effects of A. vulgaris EO on T. castaneum remain unclear. Here, two detoxifying enzymes, carboxylesterase (CarEs) and cytochrome oxidase P450 (CYPs), were dramatically increased in red flour beetle larvae when they were exposed to A. vulgaris EO. Further, 758 genes were differentially expressed between EO treated and control samples. Based on Gene Ontology (GO) analysis, numerous differentially expressed genes (DEGs) were enriched for terms related to the regulation of biological processes, response to stimulus, and antigen processing and presentation. Our results indicated that A. vulgaris EO disturbed the antioxidant activity in larvae and partially inhibited serine protease (SP), cathepsin (CAT), and lipase signaling pathways, thus disrupting larval development and reproduction as well as down-regulating the stress response. Moreover, these DEGs showed that A. vulgaris indirectly affected the development and reproduction of beetles by inducing the expression of genes encoding copper-zinc-superoxide dismutase (CuZnSOD), heme peroxidase (HPX), antioxidant enzymes, and transcription factors. Moreover, the majority of DEGs were mapped to the drug metabolism pathway in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. Notably, the following genes were detected: 6 odorant binding proteins (OBPs), 5 chemosensory proteins (CSPs), 14 CYPs, 3 esterases (ESTs), 5 glutathione S-transferases (GSTs), 6 UDP-glucuronosyltransferases (UGTs), and 2 multidrug resistance proteins (MRPs), of which 8 CYPs, 2 ESTs, 2 GSTs, and 3 UGTs were up-regulated dramatically after exposure to A. vulgaris EO. The residual DEGs were significantly down-regulated in EO exposed larvae, implying that partial compensation of metabolism detoxification existed in treated beetles. Furthermore, A. vulgaris EO induced overexpression of OBP/CYP, and RNAi against these genes significantly increased mortality of larvae exposed to EO, providing further evidence for the involvement of OBP/CYP in EO metabolic detoxification in T. castaneum. Our results provide an overview of the transcriptomic changes in T. castaneum in response to A. vulgaris EO.

Dual immunological and oxidative responses in Oreochromis niloticus fish exposed to lambda cyhalothrin and concurrently fed with Thyme powder (Thymus vulgaris L.): Stress and immune encoding gene expression

The present study was performed to explore the immunotoxicological effects of the lambda cyhalothrin (LCH) insecticide and evaluate the efficiency of Thyme powder (TP) as a fish supplement in attenuation of LCH impact on Oreochromis niloticus (O. niloticus) fish. Fish was sampled following 30-days exposure to LCH (¹/₆ LC50: 0.48 μg/L) and TP (2%) supplementation, individually or in combination. The growth performance, immune status, biochemical indices, and mRNA expression pattern changes of stress and immune-encoding genes in the liver and spleen tissues, respectively, through real-time polymerase chain reaction (RT-PCR) analysis, were evaluated. The findings showed that LCH exposure caused a significant lowering in most of the estimated variables including growth performance, hematological and immunological indices. Moreover, LCH disrupted the oxidant/antioxidant status and dysregulated the expression of stress and immune-related genes, downregulating the mRNA transcript level of Immunoglobulin M heavy chain (IgM), Interferon (IFN-γ), CXC-chemokine, and Toll-like receptors (TLR-7) in the spleen. However, mRNA expression of Myxovirus resistance (Mx) gene remained unaffected. In liver tissue, the heat shock protein (HSP-70) expression was upregulated, while that of cytochrome P450 1A (CYP 1A) was downregulated. TP (2%) supplementation elicited a significant modulation in aforementioned indices; however, their levels did not attain that of the control values. Our findings concluded that LCH affects the O. niloticus immune response through the negative transcriptional influence on genes linked to immunity and induction of oxidative injury of the immune organs. Besides, dietary TP (2%) could be a proper candidate to modulate the compromised immunity in response to LCH exposure in O. niloticus aquaculture.

Comparative Transcriptome and Proteome Analysis of Heat Acclimation in Predatory Mite Neoseiulus barkeri

In our previous study, we reported a high temperature adapted strain (HTAS) of the predatory mite Neoseiulus barkeri was artificially selected via a long-term heat acclimation (35°C) and frequent heat hardenings. To understand the molecular basis of heat acclimation, 'omics' analyses were performed to compare the differences between HTAS female adults to conventional strain (CS) at transcriptional and translational levels. We obtained a total of 5,374 differentially expressed genes and 500 differentially expressed proteins. Among them, 119 transcripts had concurrent transcription and translation profiles. It's conserved that some processes, such as high expression of heat shock protein (HSP) genes, involved in heat tolerance of transcriptome analyses, while many protective enzymes including glutathione S-transferase, superoxide dismutase, peroxidase, and cytochrome P450 displayed down-regulated expression. KEGG analysis mapped 4,979 and 348 differentially expressed genes and proteins, to 299 and 253 pathways, respectively. The mitogen-activated protein kinases (MAPK) signaling pathway may provide new insights for the investigation of the molecular mechanisms of heat tolerance. Correlation enriched pathways indicated that there were four pathways associated with heat acclimation involving in energy metabolism and immunity. In addition, the expression patterns of ten randomly selected genes including HSP were consistent with the transcriptome results obtained through quantitative real-time PCR. Comparisons between transcriptome and proteome results indicated the upregulation of HSPs and genes participated in ATP production, immunity and energy metabolism process. A majority of antioxidant-related genes and detoxication-related genes were down-regulated suggesting a fitness cost of heat acclimation. Our results demonstrated that heat tolerance during a long-time acclimation of N. barkeri is a fairly complicated process of physiological regulations. These findings also contribute to a better understanding of the mechanisms of thermal responses of phytoseiid mites which could provide useful information for biological control through natural enemies.

Effects of Diallyl Trisulfide, an Active Substance from Garlic Essential Oil, on Energy Metabolism in Male Moth Sitotroga cerealella (Olivier)

This study investigated the effects of diallyl trisulfide (DAT), an active substance from garlic essential oil, on the metabolism of the main energy substances of pre- and postmating males of Sitotroga cerealella. Males at 12 h postemergence were fumigated with DAT at a concentration (LC₁₀ = 0.010 µL/L) in a glass jar for 7 h. The main energy metabolites from pre- and postmating males were determined, including protein, triglyceride, glycogen, total soluble sugar, trehalose, and trehalase. The contents of total protein and total soluble sugar and the trehalase activity of premating males were significantly increased following DAT treatment, whereas the contents of protein from the accessory gland, triglyceride, glycogen, and trehalose were significantly decreased after treatment. Additionally, after mating, the total protein and soluble sugar contents were significantly increased and the glycogen content was significantly decreased in the treatment group relative to the levels in controls, but there was no significant difference observed in triglyceride, accessory gland proteins, trehalose content, or trehalase activity between the treatment and control groups. Furthermore, the changes in the main energy substances between pre- and postmating in males after the DAT treatment (∆DAT) were smaller than those in the control group (∆CK). This result indicated that DAT can accelerate the rate of metabolism in males at LC₁₀, leading to the accumulation of greater levels of total soluble sugar to support life activities and to the increased synthesis of proteins to resist an adverse environment.

Semisynthesis and Pesticidal Activities of Derivatives of the Diterpenoid Andrographolide and Investigation on the Stress Response of Aphis citricola Van der Goot (Homoptera: Aphididae)

To discover natural-product-based pesticides, 7β-oxycarbonylandrographolide derivatives were stereoselectively constructed from a labdane diterpenoid andrographolide. Among them, 2'-(n)Pr-1',3'-dioxin-7β-oxy(m-Cl)benzoylandrographolide (IIc), 2'-(n)Pr-1',3'-dioxin-7β-oxyacetylandrographolide (IIf), 2'-(p-Me)Ph-1',3'-dioxin-7β-oxy(o-Cl)benzoylandrographolide (Vb), and 2'-(p-Me)Ph-1',3'-dioxin-7β-oxy(m-Cl)benzoylandrographolide (Vc) against Mythimna separata displayed the most promising growth inhibitory activity; 2'-(n)Pr-1',3'-dioxin-7β-oxy(o-Cl)benzoylandrographolide (IIb: LC₅₀ = 0.406 mg/mL) and IIc (LC₅₀ = 0.415 mg/mL) exhibited the most pronounced acaricidal activity (andrographolide; LC₅₀: 5.106 mg/mL) and good control effects against Tetranychus cinnabarinus; compounds Ic, IIe, and Va-c (LD₅₀ = 0.035-0.039 μg/nymph) showed potent aphicidal activity (andrographolide: LD₅₀ = 0.178 μg/nymph), and compounds IIe and Vb showed good control effects against Aphis citricola. Moreover, it was found that Hsp70 of A. citricola was an important gene involved in stress response to andrographolide and its derivatives.