Transmission Of Plant Viruses Research Articles

New Biocompatible Technique Based on the Use of a Laser to Control the Whitefly Bemisia tabaci

The whitefly Bemisia tabaci is among the most important agricultural pests in the world and one of the world’s top 10 most invasive insect pests. Bemisia tabaci is associated with severe yield and quality losses, mainly due to the transmission of plant viruses, as in the case of common beans (Phaseolus vulgaris L.). Reducing insecticide applications is a research priority, e.g., developing innovative and clean tools such as electromagnetic waves. The present work aims to determine the effective parameters of laser to reduce the Bemisia tabaci population in common beans. Preliminary assays were conducted by manually irradiating continuous-wave laser beams with different wavelengths (444 nm, 527 nm, and 640 nm) and optical intensities directly on the insects. Among these, the most effective wavelength was 444 nm. Later, we repeated the experiments using a homemade automated system to control the exposure time (t1 = 1 s, t2 = 2 s, t3 = 3 s and t4 = 4 s) of whiteflies to the incident beam at different optical intensities (I1 ≈ 10 Wcm−2, I2 ≈ 4 Wcm−2, I3 ≈ 2 Wcm−2). We have achieved 100% insect mortality by irradiating 454 nm laser wavelength on the 3rd instar nymphs of Bemisia tabaci, with the following parameters: I1(t1), I2(t3) and I3(t4). Moreover, the laser irradiation test did not affect plant yield and development, revealing that our preliminary results present a photonic technique that could control whiteflies without harming the plants’ development.

Characterization of the seed virome of alfalfa (Medicago sativa L)

BackgroundSeed transmission of plant viruses can be important due to the role it plays in their dissemination to new areas and subsequent epidemics. Seed transmission largely depends on the ability of a virus to replicate in reproductive tissues and survive during the seed maturation process. It occurs through the infected embryo or mechanically through the contaminated seed coat. Alfalfa (Medicago sativa L.) is an important legume forage crop worldwide, and except for a few individual seedborne viruses infecting the crop, its seed virome is poorly known. The goal of this research was to perform initial seed screenings on alfalfa germplasm accessions maintained by the USDA ARS National Plant Germplasm System in order to identify pathogenic viruses and understand their potential for dissemination.MethodsFor the detection of viruses, we used high throughput sequencing combined with bioinformatic tools and reverse transcription-polymerase chain reactions.ResultsOur results suggest that, in addition to common viruses, alfalfa seeds are infected by other potentially pathogenic viral species that could be vertically transmitted to offspring.ConclusionsTo the best of our knowledge, this is the first study of the alfalfa seed virome carried out by HTS technology. This initial screening of alfalfa germplasm accessions maintained by the NPGS showed that the crop’s mature seeds contain a broad range of viruses, some of which were not previously considered to be seed-transmitted. The information gathered will be used to update germplasm distribution policies and to make decisions on the safety of distributing germplasm based on viral presence.

Double sodium channel mutation, I265T/L1014F, is possibly related to pyrethroid-resistant in Thrips palmi.

Thrips palmi Karny (Thysanoptera: Thripidae) can harm a variety of agricultural crops and transmit plant viruses, causing heavy economic losses. In the Hainan province of China, pyrethroids were sprayed widely to control T. palmi, which leaded to resistance to pyrethroids in T. palmi. The bioassay has shown that the resistance ratio of T. palmi to pyrethroids increases annually. Resistance ratio to λ-cyhalothrin has increased from 10.711 to 23.321 and to cypermethrin has increased from 5.507 to 23.051 for 3 years, 2020-2022. The double mutation (I265T/L1014F) was identified from the field strain for the first time, which were located in the domains I and II of the voltage-gated sodium channel of T. palmi, respectively. The double mutation is probably the reason for the higher resistance of T. palmi in Hainan. The frequencies of the double mutation were 53.33% in HN2020, 70.00% in HN2021, and 96.67% in HN2022. Results indicated that T. palmi had developed different degrees of resistance to pyrethroids in Hainan. This study provides theoretical guidance for the use of insecticides in the field control of thrips.

Pest categorisation of Nilaparvata lugens

The EFSA Panel on Plant Health performed a pest categorisation of Nilaparvata lugens (Hemiptera: Delphacidae), the brown planthopper, for the European Union. N. lugens is widespread in Asia where it is native; it also occurs in Oceania where it is naturalised. N. lugens is not known to be present in the EU and is not listed in Annex II of Commission Implementing Regulation (EU) 2019/2072. It is a monophagous species and a major pest of rice (Oryza sativa). High populations of planthoppers cause leaves to initially turn orange yellow before becoming brown and dry and this is a condition called 'hopperburn' that kills the plant. N. lugens can also transmit plant viruses. It can complete 12 generations per year in tropical areas, where it resides year-round. N. lugens can undertake long-distance migration of up to 500 km from tropical areas to form transient populations in sub-tropical and temperate areas but due to low temperatures and absence of rice plants during the winter it does not establish in such areas. Entry to the EU via migration is unlikely given the distance from tropical rice growing areas. A possible but unlikely potential pathway is the import of infested rice seedlings, although we have no evidence that such trade exists. In the EU, rice is mainly planted from seed; when transplanted, it is sourced locally. N. lugens is very unlikely to survive year-round in the EU due to unsuitable climate and lack of hosts during the winter. Consequently, the pest is very unlikely to become established in the EU territory. Nevertheless, there are measures available to further reduce the likelihood of entry, establishment and spread of N. lugens within the EU. N. lugens does not satisfy the criteria that are within the remit of EFSA to assess for it to be regarded as a potential Union quarantine pest.

Two salivary proteins Sm10 and SmC002 from grain aphid Sitobion miscanthi modulate wheat defense and enhance aphid performance.

The grain aphid Sitobion miscanthi is a serious pest of wheat that causes severe economic damage by sucking phloem sap and transmitting plant viruses. Here, two putative salivary effector homologs from S. miscanthi (Sm10 and SmC002) were selected based on sequence similarity to other characterized aphid candidate effectors. These effectors were then delivered into wheat cells separately via the type III secretion system of Pseudomonas fluorescens to elucidate their functions in the regulation of plant defenses and host fitness. The results showed that the delivery of either Sm10 or SmC002 into wheat plants significantly suppressed callose deposition and affected the transcript levels of callose synthase genes. The expression levels of salicylic acid (SA)-associated defense genes were upregulated significantly in wheat leaves carrying either Sm10 or SmC002. Moreover, LC-MS/MS analysis revealed that wheat SA levels significantly increased after the delivery of the two effectors. The results of aphid bioassays conducted on the wheat plants carrying Sm10 or SmC002 showed significant increases in the survival and fecundity of S. miscanthi. This study demonstrated that the Sm10 and SmC002 salivary effectors of S. miscanthi enhanced host plant susceptibility and benefited S. miscanthi performance by regulating wheat defense signaling pathways.

The JAK-STAT pathway promotes persistent viral infection by activating apoptosis in insect vectors.

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway is an evolutionarily conserved signaling pathway that can regulate various biological processes. However, the role of JAK-STAT pathway in the persistent viral infection in insect vectors has rarely been investigated. Here, using a system that comprised two different plant viruses, Rice stripe virus (RSV) and Rice black-streaked dwarf virus (RBSDV), as well as their insect vector small brown planthopper, we elucidated the regulatory mechanism of JAK-STAT pathway in persistent viral infection. Both RSV and RBSDV infection activated the JAK-STAT pathway and promoted the accumulation of suppressor of cytokine signaling 5 (SOCS5), an E3 ubiquitin ligase regulated by the transcription factor STAT5B. Interestingly, the virus-induced SOCS5 directly interacted with the anti-apoptotic B-cell lymphoma-2 (BCL2) to accelerate the BCL2 degradation through the 26S proteasome pathway. As a result, the activation of apoptosis facilitated persistent viral infection in their vector. Furthermore, STAT5B activation promoted virus amplification, whereas STAT5B suppression inhibited apoptosis and reduced virus accumulation. In summary, our results reveal that virus-induced JAK-STAT pathway regulates apoptosis to promote viral infection, and uncover a new regulatory mechanism of the JAK-STAT pathway in the persistent plant virus transmission by arthropod vectors.

Diversity and Regional Variation of Endosymbionts in the Green Peach Aphid, Myzus persicae (Sulzer)

The green peach aphid, Myzus persicae, is globally distributed and an important pest of many economically valuable food crops, largely due to its ability to transmit plant viruses. Almost all aphids, including M. persicae, carry the obligate symbiont Buchnera aphidicola, which provides essential amino acids that aphids cannot obtain from the phloem of plants themselves. Many aphids also harbor facultative (secondary) endosymbionts, which provide benefits under specific ecological conditions. In this study, we screened for secondary endosymbionts in M. persicae, with a particular focus on Australian populations where this species is growing in status as a major agricultural pest. We compared 37 Australian M. persicae populations with other populations, including 21 field populations from China and 15 clones from the UK, France, Italy, Greece, USA, Spain, South Korea, Chile, Japan and Zimbabwe. No secondary endosymbionts were identified in M. persicae samples outside of China, despite samples covering a wide geographic range and being collected from several host plant families. We detected two secondary endosymbionts (Rickettsia, Spiroplasma) in Chinese samples, although diversity appeared lower than detected in a recent study. We also found very high clonal diversity in Chinese samples based on DNA microsatellite markers in comparison with lower clonal diversity from Australia. These patterns may indicate a higher diversity of secondary endosymbionts (and clonal diversity) in the native range of M. persicae when compared to its invasive range.

Detection of Laodelphax striatellus (small brown planthopper) based on improved YOLOv5

Laodelphax striatellus (small brown planthopper, SBPH) is a pest feeding mainly on rice, wheat and corn. Meanwhile, SBPH transmits plant viruses during feeding, which may take more serious damage to the agriculture. The research of SBPH control has great significance. Most of the traditional SBPH detection and counting problems are conducted manually, which is inefficient. In this paper, we proposed the improved YOLOv5s algorithm to implement the recognition and counting the system of SBPH. We improve the YOLOv5s based on the channel attention and spatial attention, adding the Convolutional Block Attention Module (CBAM) to YOLOv5s. In order to fuse the feature information of different scales to improve the model, we add the Adaptively Spatial Feature Fusion (ASFF). Experiments prove that the improved model volume is not much different from YOLOv5s, which is one-seventh of YOLOv5x, but the mAP of the improved model is approximately 4 % better than YOLOv5s and 2 % better than YOLOv5x. Finally, an APP was developed using Android Studio. We developed image recognition, counting module, real-time recognition and counting module, which were migrated to the mobile phone.

A novel salivary effector, BtE3, is essential for whitefly performance on host plants.

The whitefly Bemisia tabaci is a piercing-sucking herbivore that reduces the yields of crops both by feeding on plants and transmitting plant viruses. Like most plant feeders, B. tabaci has evolved ways to avoid plant defence responses. For example, B. tabaci is known to secrete salivary effectors to suppress host defences. However, the nature of B. tabaci effectors is not completely understood. In this study, we used B. tabaci genomic and salivary gland transcriptomic data and an overexpression system to identify a previously unknown B. tabaci salivary effector, BtE3. BtE3 is specifically expressed in the head (containing primary salivary glands) and is secreted into hosts during B. tabaci feeding. In planta overexpression of BtE3 blocked Burkholderia glumae-induced hypersensitive response (HR) in both Nicotiana benthamiana and Solanum lycopersicum. Silencing of BtE3 by plant-mediated RNAi prevented B. tabaci from continuously ingesting phloem sap, and reduced B. tabaci survival and fecundity. Moreover, overexpression of BtE3 in planta up-regulated the salicylic acid- (SA-) signalling pathway, but suppressed the downstream jasmonic acid- (JA-) mediated defences. Taken together, these results indicate that BtE3 is a B. tabaci-specific novel effector involved in B. tabaci-plant interactions. These findings increase our understanding of B. tabaci effectors and suggest novel strategies for B. tabaci pest management.

Mealybug vectors: A review of their transmission of plant viruses and their management strategies

<abstract> <p>Mealybugs cause mechanical damage and diseases to plants. Through their feeding activities, they reduce the yield, quality and productivity of crops. This review discusses mealybug vectors of plant viruses, the economic losses they cause, mealybug species and their hosts. Among the numerous mealybug species, <italic>Planococcus</italic> species are the most effective vector of plant viruses, transmitting many Ampeloviruses. Diverse methods for the control and regulation of mealybugs are also discussed. Physical, cultural and biological control methods are labor-intensive but environmentally friendly compared to chemical methods. However, chlorpyrifos are one the active ingredients of insecticides effective against several mealybug species. Using plant products such as neem oil as a biocontrol method has been effective, similar to other insecticides. Notwithstanding, the biological method of controlling mealybugs is effectively slow but safe and highly recommended. The Anagyrus species have the highest success rate amongst other natural parasites of mealybugs. Also, farm sanitation and pruning as cultural methods help reduce mealybug populations.</p> </abstract>

Comparative Transcriptomic Analysis of Head in Laodelphax striatellus upon Rice Stripe Virus Infection

Rice stripe virus (RSV) is transmitted by the small brown planthopper (SBPH), Laodelphax striatellus, in a circulative-propagative manner. Multiple studies have proved that RSV can manipulate vector insects to facilitate its transmission and can alter the gene expressions in viruliferous SBPH. However, to the best of our knowledge, nobody has investigated the gene expressions in the head of SBPH after RSV acquisition. In this study, to investigate the genes and gene functions regulated by RSV infection in the head of SBPH, we used RNA sequencing to compare the transcriptional profiles between SBPH head samples that acquired RSV or not. Compared with the non-viruliferous SBPH, a total of 336 differentially expressed genes (DEGs) were identified in the head samples of viruliferous SBPH groups, including 186 up-regulated and 150 down-regulated genes. Here, we focused on DEGs that may be involved in RSV replication or transmission, primarily genes associated with the nervous system, cytochrome P450s, sugar metabolism, the olfactory system, and cuticular process, as well as genes that have been previously reported to affect virus transmission in insect vectors including ubiquitin-protein ligase (E3), ecdysone response gene (E74A), and vitellogenin receptor (VgR). Finally, we verified the accuracy of the transcriptome sequencing results using qRT-PCR by selecting 16 DEGs. Our results can contribute to the understanding of the effects of RSV infection on gene regulation in the head of SBPH and provide insight into the control of plant virus transmission and insect vectors.

Evaluation of chilli genotypes and understanding biochemical basis of whitefly (Bemisia tabaci Genn.) resistance

• Two resistant genotypes (IHR 4300 and IHR 4338) have been identified. • Cuticle thickness significantly negative correlated with adult survival, oviposition and nymphal population of whiteflies. • Higher concentration of phenolics and flavonoids are metabolic candidates for indirect selection of resistant genotypes. Whitefly is most devastating insect pest which causes damage by direct feeding on the host plant and also act as vector for transmission of many plant viruses causing severe yield losses in chilli. Host plant resistance is best advocated strategy in controlling the damage. We have screened the selected genotypes for white fly resistance using more accurate no-choice screening assays. Three types of assays i.e. clip-on-cage, detached branch and detached leaf methods of screening have been followed. Two resistant genotypes (IIHR 4300 and IIHR 4338) have been identified based on highest adult mortality, low oviposition rate, higher egg mortality and nymphal death. Cuticle thickness found significantly negative correlated with adult survival, oviposition and nymphal population. Semio-chemicals differing significantly amongst resistant and susceptible genotypes were identified through GC–MS and LC-MS and these can be used as metabolic candidates for indirect selection in screening genotypes/ populations for resistance. These two resistant chilli genotypes viz ., IIHR 4300 and IIHR 4338 can be explored for breeding for white fly resistance.

Discovery of novel whitefly vector proteins that interact with a virus capsid component mediating virion retention and transmission

Specificity and efficiency of plant virus transmission depend largely on protein-protein interactions of vectors and viruses. Cucurbit chlorotic yellows virus (CCYV), transmitted specifically by tobacco whitefly, Bemisia tabaci, in a semi-persistent manner, has caused serious damage on cucurbit and vegetable crops around the world. However, the molecular mechanism of interaction during CCYV retention and transmission are still lacking. CCYV was proven to bind particularly to the whitefly foregut, and here, we confirmed that the minor coat protein (CPm) of CCYV is participated in the interaction with the vector. In order to identify proteins of B. tabaci that interact directly with CPm of CCYV, the immunoprecipitation (IP) assay and DUALmembrane cDNA library screening technology were applied. The cytochrome c oxidase subunit 5A (COX), tubulin beta chain (TUB) and keratin, type I cytoskeletal 9-like (KRT) of B. tabaci shown strong interactions with CPm and are closely associated with the retention within the vector and transmission of CCYV. These findings on whitefly protein-CCYV CPm interactions are crucial for a much better understanding the mechanism of semi-persistent plant virus transmission by insect vectors, as well as for implement new strategies for effective management of plant viruses and their vector insects.

Identification and Expression Analysis of Odorant-Binding and Chemosensory Protein Genes in Virus Vector Nephotettix cincticeps.

The insect odorant binding proteins (OBPs) and chemosensory proteins (CSPs) are involved in the perception and discrimination of insects to host odor cues. Nephotettix cincticeps, one of the destructive pests of rice plants, not only directly damages hosts by sucking, but also indirectly transmits plant viruses in the field. Previous study found that two rice volatiles ((E)-β-caryophyllene and 2-heptanol) induced by rice dwarf virus (RDV) mediated the olfactory behavior of N. cincticeps, which may promote virus dispersal. However, the OBPs and CSPs in N. cincticeps are still unknown. In this study, to identify the OBP and CSP genes in N. cincticeps, transcriptomic analyses were performed. In total, 46,623 unigenes were obtained. Twenty putative OBP and 13 CSP genes were discovered and identified. Phylogenetic analyses revealed that five putative OBPs belonged to the plus-C OBP family, and the other classic OBPs and CSPs were distributed among other orthologous groups. A total of 12 OBP and 10 CSP genes were detected, and nine OBP and three CSP genes were highly expressed in N. cincticeps antennae compared with other tissues. This study, for the first time, provides a valuable resource to well understand the molecular mechanism of N. cincticeps in the perception and discrimination of the two volatiles induced by RDV infection.

Toxicity and synergistic activity of compounds from essential oils and their effect on detoxification enzymes against Planococcus lilacinus.

Mealybug, Planococcus lilacinus Cockerell, is a primary surface-feeding insect pest of fruit and flowering plants and also transmits plant viruses, resulting in economic crop loss. Inappropriate and recurrent use of pesticides for mealybug control results in resistance building and deleterious effects on humans and the environment. Essential oils are the most excellent choice for insecticides. Insecticidal activities of pure compounds of essential oils against P. lilacinus are not reported. The present study aims to study the insecticidal activities of some pure active compounds and their binary mixture's action by topical application against P. lilacinus. Results showed that the pure compounds of L-limonene, β-myrcene, and ocimene revealed toxicity (each at LD50 = 0.37 µg/insect) after 96h. The binary mixtures of geraniol + L-menthol and L-limonene + geraniol exhibited synergistic effects (each at LD50 = 0.03 µg/insect) after 96h. The monoterpenes of ocimene and β-myrcene at the higher concentration of 5,000 ppm substantially inhibited the detoxification enzyme activities of AChE (0.93 and 0.78 mU/mg, respectively) and GST (2.19 and 7.29 nmol/min/ml, respectively) in P. lilacinus after 48h. SEM analysis reported the significant anomalies on the morphology of abdominal cuticle, setae, and thoracic leg after 96-h treatment with ocimene at 1,250 ppm against P. lilacinus. Based on the results, the tested pure compounds and their combinations can be suggested for the control of mealybugs.

Catalyzing systemic movement of inward rectifier potassium channel inhibitors for antifeedant activity against the cotton aphid, Aphis gossypii (Glover).

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, capable of photosynthate removal and plant virus transmission. Therefore, we aimed to test the antifeedant properties of small-molecule inhibitors of inward rectifier potassium (Kir) channels expressed in insect salivary glands and develop an approach for enabling systemic movement of lipophilic Kir inhibitors. Two Kir channel inhibitors, VU041 and VU730, reduced the secretory activity of the aphid salivary glands by 3.3-fold and foliar applications of VU041 and VU730 significantly (P < 0.05) increased the time to first probe, total probe duration, and nearly eliminated phloem salivation and ingestion. Next, we aimed to facilitate systemic movement of VU041 and VU730 through evaluation of a novel natural product based solubilizer containing rubusoside that was isolated from Chinese sweet leaf (Rubus suavissimus) plants. A single lower leaf was treated with Kir inhibitor soluble liquid (KI-SL) and systemic movement throughout the plant was verified via toxicity bioassays and changes to feeding behavior through the electrical penetration graph (EPG) technique. EPG data indicate KI-SL significantly reduced ability to reach E1 (phloem salivation) and E2 (phloem ingestion) waveforms and altered plant probing behavior when compared to the untreated control. High-performance liquid chromatography (HPLC) analysis indicated the presence of VU041 and VU730 in the upper leaf tissue of these plants. Together, these data provide strong support that incorporation of rubusoside with Kir inhibitors enhanced translaminar and translocation movement through the plant tissue. These data further support hemipteran Kir channels as a target to prevent feeding and induce toxicity. Further, these studies highlight a novel delivery approach for generating plant systemic activity of lipophilic insecticides. © 2022 Society of Chemical Industry.

The transmission of plant viruses

Abstract Plant viruses are a threat to a sustainable economy because they cause economic losses in yields. The epidemiology of plant viruses is of particular interest because of their dynamic spread by insect vectors and their transmission by seeds. The speed and direction of viral evolution are determined by the selective environment in which they are found. Knowledge of the ecology of plant viruses is critical to the transmission of many plant viruses. Accurate and timely detection of plant viruses is an essential part of their control. Rapid climate change and the globalization of trade through free trade agreements encourage the transmission of vectors and viruses from country to country. Another factor affecting the emergence of viruses is the cultivation of monocultures with low genetic diversity a nd high plant density. Trade in plant material (germplasm and living plants) also cause the emergence of new viruses. Viruses have a fast adaptation and development in a new environment. Aphids are the most widespread and important vectors of plant viruses. Myzus persicae transmits more than 100 different plant viruses. In nature plant viruses are transmitted also by nematodes, fungi, mites, leafhoppers, whiteflies, beetles, and planthoppers. The symptoms of viral diseases are very diverse and are often confused with symptoms of abiotic stress. Control of viral diseases is based on two strategies: i) immunization (genetic resistance acquired by plant transformation, breeding, or cross-protection), ii) prophylaxis to limit viruses (removal of infected plants and control of their vectors). For management, we rely on quick and accurate identification of the disease.

Identification of azukisapogenol triterpenoid saponins from Oxytropis hirta Bunge and their aphicidal activities against pea aphid Acyrthosiphon pisum Harris.

Acyrthosiphon pisum Harris is the most destructive pest worldwide because of its ability to feed on plants directly and transmit plant viruses as a vector. This study aims to identify triterpenoid saponins from Oxytropis hirta Bunge as biopesticides to control aphids. Three new azukisapogenol triterpenoid saponins (1-3), a new pinoresinol lignan glycoside (8), and four known saponins (4-7) were identified from the root of O. hirta. Compounds 4-7 displayed significant aphicidal activities against A. pisum with oral toxicities (LC50 =51.10-147.43 μg/mL, 72 h), deterrent effects (deterrence index=1.00, 100-200 μg/mL, 24 h), and aphid reproduction inhibitory effects (inhibition rates=75.91-86.73%, 400 μg/mL, 24 h), respectively. The carboxyl groups at C-3 GlcA and C-30 were functional groups for their aphicidal activities. The toxic symptoms caused by the optimal 5 involved insect body-color changes from light green to dark or gray-green, and then brown until death. The intestinal cavity, apical microvilli, nuclei, mitochondria, and electron dense granules in the midgut tissues of A. pisum were the target sites showing aphicidal activity. The suppression of pepsin and α-amylase, and the activation of lipase and trypsin could be the signs of organelle damage in the midgut tissues. Azukisapogenol triterpenoid saponins from O. hirta could be used as biopesticides to control aphids for their multiple efficacies, including oral toxicity, deterrent activity, and reproduction inhibitory activity. The toxic symptoms involved insect body-color changes. Midgut tissues and their related enzymes were the targets for saponins showing aphicidal activities. © 2022 Society of Chemical Industry.

Mineral oil interferes with potato virus Y in aphid stylets

AbstractMineral oils have been used for many decades to control the transmission of plant viruses and their ensuing epidemics. Although it is not clearly defined, the mode of action of these oils has been extensively studied, and effects on the feeding behaviour and orientation of the vector or the transmission of the virus by its vector have often been put forward as possible explanations. This study examines the effect of mineral oil on the interaction between potato virus Y (PVY) and its vector, the green peach aphid Myzus persicae, with particular focus on the transmission organ. A lipophilic staining technique was used to visualize the oil inside the insect's stylets for the first time. Virus binding and localization were also examined in aphid stylets following PVY acquisition. The results indicate that the presence of mineral oil on leaves reduces the likelihood of acquiring the virus. This study verified that this reduced acquisition could be accompanied by a reduction in viral load, as measured by reverse transcription‐quantitative PCR on the stylets. The effect of the oil on virus retention inside the stylets was also measured. The mechanism by which the oil impacts virus acquisition seems to take place in the very early stages of acquisition, well before the virus attaches to the stylets.

Bta06987, Encoding a Peptide of the AKH/RPCH Family: A Role of Energy Mobilization in Bemisia tabaci.

Simple SummaryBta06987 gene encodes a peptide that belongs to the AKH/RPCH family. Members of this family exert essential effects on energy metabolism and other physiological and biological processes. Bemisia tabaci is a crop pest, causing crop losses mainly through feeding and transmission of plant viruses. There are only a few reports about AKH family in B. tabaci. In our study, we report on the characterization of the neuropeptide precursor encoded by Bta06987 in B. tabaci at the molecular level and provide evidence for its essential function in energy homeostasis. Moreover, through an electrical penetration graph experiment, we found that manipulation of the relative expression of Bta06987 effected the feeding behavior of B. tabaci. The findings in this paper can be used toward developing strategies aimed at decreasing the feeding time of B. tabaci, which might be useful for controlling pests and plant virus transmission.A neuropeptide precursor encoded by Bta06987 associates with AKH neuropeptide. In the AKH/RPCH family, these members have been demonstrated to participate in energy mobilization in many insects. In our research, the Bta06987 gene from Bemisia tabaci was cloned, and the amino acid sequence analysis was performed. During the starvation of B. tabaci, the mRNA level of Bta06987 showed a significant elevation. We investigated the functions of Bta06987 in B. tabaci using RNA interference (RNAi), and the adult females of B. tabaci after being fed with dsBta06987 showed a higher glycogen and triglyceride levels and lower trehalose content than the control. Furthermore, in the electrical penetration graph (EPG) experiment, B. tabaci showed changes in feeding behavior after feeding with dsBta06987, such as the reduction in parameters of E waveform percentage and total feeding time. Our findings might be helpful in developing strategies to control pest and plant virus transmission.