Green Peach Aphid Myzus Research Articles

Life table and feeding behavior of Myzus persicae (Hemiptera: Aphididae) at sublethal concentrations of Afidopyropen, Spirotetramat and sulfoxaflor

AbstractThe green peach aphid Myzus persicae Sülzer is a major insect pest of cruciferous plants, including vegetables such as Chinese cabbage. The objective of the present study was to determine the effects of sublethal afidopyropen and spirotetramat concentrations on the survival and reproduction of M. persicae. In addition, we used an electrical penetration graph (EPG) to study the feeding behavior of M. persicae on Chinese cabbage leaves treated with various concentrations of afidopyropen, spirotetramat and sulfoxaflor. The results showed that sublethal concentrations (LC10 and LC30) of afidopyropen and spirotetramat significantly decreased adult longevity and fecundity. However, sulfoxaflor had no significant effects. Several population parameters, including the net reproductive rate (R0), intrinsic rate of increase (rm), mean generation time (T), finite rate of increase (λ), and doubling time (DT), were significantly decreased only at the LC30 of spirotetramat. According to the EPG feeding behavior analyses, when all three insecticides were applied at LC30, the nonpenetration (NP) waveform significantly increased. The above results can be used as basic data for the well‐planned use of insecticides.

Bell pepper endornavirus alters green peach aphid (Hemiptera: Aphididae) host choice and population dynamics.

Bell pepper endornavirus (BPEV) Alphaendornavirus capsici (Endornaviridae) is an RNA virus that infects many pepper (Capsicum annuum) horticultural types and is seed transmitted. BPEV does not cause apparent symptoms and is found at every plant developmental stage. During the domestication of bell pepper, plant breeders, unaware of the existence of endornaviruses in the germplasm, selected endornavirus-infected genotypes. This could be an indication that the presence of endornaviruses in this crop is beneficial. Among the possible beneficial effects that endornaviruses may provide to their host could include tolerance or resistance to biotic and abiotic agents and, therefore, may have evolved a symbiotic relationship with their hosts. With this in mind, we set out to determine host preference, host suitability, and population dynamics of green peach aphid Myzus persicae (Sulzer) on BPEV-infected and virus-free bell pepper near-isogenic lines. During choice bioassay experiments, we observed that a higher proportion of M. persicae adults settled on BPEV noninfected leaves as compared to BPEV-infected leaves. Life table analysis revealed that M. persicae performed less well on BPEV-infected leaf tissues, with reductions in longevity, progeny, and intrinsic rate of increase. These results indicate BPEV is beneficial to its host, protecting against an important generalist pest.

Transcriptional and physiological plasticity of the green peach aphid (Hemiptera: Aphididae) to cabbage and pepper plants.

Defensive metabolites and nutrient restriction of host plants are 2 major obstacles to the colonization of insect herbivores. The green peach aphid (GPA) Myzus persicae (Sulzer) broadly colonizes plants with diverse nutritional and defensive traits. However, how GPA adapts to nutritional and defensive traits within different plants remains largely unknown. To elucidate this, we first investigated the performances and transcriptomes of GPA feeding on cabbage Brassica oleracea and pepper Capsicum annuum. The green peach aphid had lower weight and fecundity when feeding on cabbage than on pepper. The transcriptomic analysis found 824 differentially expressed genes (DEGs), and 13 of the top 20 Kyoto Encyclopedia of Genes and Genomes pathways are related to nutrient metabolism, energy metabolism, and detoxification. Specifically, we found 160 DEGs associated with the metabolism of protein and amino acids, sugar and lipids, and xenobiotic substances, 86 upregulated in cabbage-fed GPA. Fourteen cathepsin B genes were strongly upregulated in cabbage-fed GPA, and were enriched in lysosome pathway and 2 dominated gene ontology terms peptidase activity and proteolysis. In addition, cabbage-fed GPA upregulated sugar and lipid digestion, while downregulated lipid biosynthesis processes. Furthermore, 55 metabolic detoxification enzyme genes were differentially expressed between GPA on 2hosts, and detoxification enzyme activities of GPA indeed changed accordingly to the host. Then, we found that cabbage has lower amino acids nutrition quality for GPA compared to pepper. Our results suggested that adjustment of nitrogen nutrient metabolism, sugar and lipid metabolism, and metabolic detoxification in a host-specific manner play crucial roles in the adaptations of GPA to different host plants.

Interplay between a polerovirus and a closterovirus decreases aphid transmission of the polerovirus.

Multi-infection of plants by viruses is very common and can change drastically infection parameters such as virus accumulation, distribution, and vector transmission. Sugar beet is an important crop that is frequently co-infected by the polerovirus beet chlorosis virus (BChV) and the closterovirus beet yellows virus (BYV), both vectored by the green peach aphid (Myzus persicae). These phloem-limited viruses are acquired while aphids ingest phloem sap from infected plants. Here we found that co-infection decreased transmission of BChV by ~50% but had no impact on BYV transmission. The drastic reduction of BChV transmission was due to neither lower accumulation of BChV in co-infected plants nor reduced phloem sap ingestion by aphids from these plants. Using the signal amplification by exchange reaction fluorescent in situ hybridization technique on plants, we observed that 40% of the infected phloem cells were co-infected and that co-infection caused redistribution of BYV in these cells. The BYV accumulation pattern changed from distinct intracellular spherical inclusions in mono-infected cells to a diffuse form in co-infected cells. There, BYV co-localized with BChV throughout the cytoplasm, indicative of virus-virus interactions. We propose that BYV-BChV interactions could restrict BChV access to the sieve tubes and reduce its accessibility for aphids and present a model of how co-infection could alter BChV intracellular movement and/or phloem loading and reduce BChV transmission.IMPORTANCEMixed viral infections in plants are understudied yet can have significant influences on disease dynamics and virus transmission. We investigated how co-infection with two unrelated viruses, BChV and BYV, affects aphid transmission of the viruses in sugar beet plants. We show that co-infection reduced BChV transmission by about 50% without affecting BYV transmission, despite similar virus accumulation rates in co-infected and mono-infected plants. Follow-up experiments examined the localization and intracellular distribution of the viruses, leading to the discovery that co-infection caused a redistribution of BYV in the phloem vessels and altered its repartition pattern within plant cells, suggesting virus-virus interactions. In conclusion, the interplay between BChV and BYV affects the transmission of BChV but not BYV, possibly through direct or indirect virus-virus interactions at the cellular level. Understanding these interactions could be crucial for managing virus propagation in crops and preventing yield losses.

JAK/STAT signaling pathway is involved in antibacterial immunity in the green peach aphid Myzus persicae (Sulzer)

The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway within the innate immune system plays a crucial role in defending insects against bacterial, fungal, and viral pathogens. In this study, we identified and cloned five key genes of this signaling pathway in Myzus persicae: MpDome-1, MpDome-2, MpJak, MpStat92E-1, and MpStat92E-2. Our results illustrated that these genes were highly expressed in first, second and third-instar nymphs. Tissue-specific expression analysis revealed that the five genes were predominantly expressed in the gut. Upon bacterial challenge, particularly with Staphylococcus aureus, the expression levels of all five genes were significantly upregulated. Additionally, Escherichia coli infection significantly upregulated the expression levels of MpDome-1 and MpDome-2, while MpJak, MpStat92E-1 and MpStat92E-2 were weakly upregulated. Functional analysis through RNA interference-mediated knockdown of these target genes revealed a significant increase in mortality following infection with E. coli and S. aureus compared with the control group. These findings suggest that the JAK/STAT signaling pathway is crucial for immune defense against bacterial infections in M. persicae.

Influence of genetic and environmental factors on the success of endosymbiont transfers in pest aphids.

There is increasing interest in exploring how endosymbionts could be useful in pest control, including in aphids, which can carry a diversity of endosymbionts. Endosymbionts often have a large impact on host traits, and their presence can be self-sustaining. Identifying useful host-endosymbiont combinations for pest control is facilitated by the transfer of specific endosymbionts into target species, particularly if the species lacks the endosymbiont. Here, we complete a comprehensive literature review, which included 56 relevant papers on endosymbiont transfer experiments in aphids, to uncover factors that might influence transfer success. We then report on our own microinjection attempts of diverse facultative endosymbionts from a range of donor species into three agriculturally important aphid species as recipients: the green peach aphid (Myzus persicae), bird cherry-oat aphid (Rhopalosiphum padi), and Russian wheat aphid (Diuraphis noxia). Combining this information, we consider reasons that impact the successful establishment of lines carrying transferred endosymbionts. These include a lack of stability in donors, deleterious effects on host fitness, the absence of plant-based (versus vertical) transmission, high genetic variation in the endosymbiont, and susceptibility of an infection to environmental factors. Taking these factors into account should help in increasing success rates in future introductions.

Transgenic cotton expressing Allium sativum leaf agglutinin exhibits resistance to whiteflies and aphids without negative effects on ladybugs

Cotton (Gossypium hirsutum L.) is of great economic importance as a cultivated crop in many parts of the world. In addition to being a pillar of the textile industry, cotton and its byproducts are used for livestock feed, seed oil, and other products. Bacillus thuringiensis crystal toxin (Bt) expression in cotton provides effective protection against chewing insects but does not defend plants from piercing/sucking insect pests. With the aim to create transgenic plants with resistance against piercing/sucking pests, we used Agrobacterium-mediated genetic transformation of cotton cultivar Coker 312 to express the Allium sativum leaf agglutinin (ASLA) gene from the phloem-specific rolC promoter. The ASLA transgene was stably inherited and showed Mendelian segregation in the T1 generation. Transgenic lines, expressing the ASLA gene, showed explicit resistance against major sap-sucking pests. Green peach aphid (Myzus persicae Sulzer) choice assays showed that 75% of aphids preferred untransformed cotton plants relative to those expressing the ASLA gene. In detached leaf bioassays, plants expressing ASLA caused 82% aphid mortality and 44–53% reduction in fecundity. Clip cage bioassays with whiteflies (Bemisia tabaci Gennadius) showed 74–82% mortality and 44–60% decrease in fecundity due to ASLA gene expression. In whole plant bioassays, whiteflies showed 77% mortality and a 54% decrease in fecundity on ASLA transgenics. Importantly, we did not observe a negative effect of the ASLA gene on ladybugs (Coccinella septempunctata) that consumed these whiteflies. Together, our findings demonstrate the potential of ASLA-transgenic cotton for providing protection against two devastating insect pests, whiteflies and aphids. The ASLA-transgenic cotton appears promising for direct commercial cultivation besides serving as a potential genetic resource in recombination breeding.

Synergistic Insecticidal Interaction of <i>Aegle marmelos</i> and <i>Mentha piperita</i> against <i>Myzus persicae</i>

The efficacy of natural pesticides derived from Aegle marmelos and Mentha piperita leaves was investigated against green peach aphids (Myzus persicae). The extracts obtained via boiling and soxhlet methods from A. marmelos and M. piperita leaves were combined and tested for synergistic effects. The results indicate a 100% efficacy rate at a concentration of 500 ppm (A. marmelos) + 400 ppm (M. piperita), highlighting the potential of these botanical extracts as ecofriendly alternatives.

Unraveling jasmonate-mediated plant immunity against green peach aphid (Myzus persicae) in peach: an integrated transcriptomic and RNA sequencing approach

Unraveling jasmonate-mediated plant immunity against green peach aphid (Myzus persicae) in peach: an integrated transcriptomic and RNA sequencing approach

Densovirus infection facilitates plant-virus transmission by an aphid.

The interactions among plant viruses, insect vectors, and host plants have been well studied; however, the roles of insect viruses in this system have largely been neglected. We investigated the effects of MpnDV infection on aphid and PVY transmission using bioassays, RNA interference (RNAi), and GC-MS methods and green peach aphid (Myzus persicae (Sulzer)), potato virus Y (PVY), and densovirus (Myzus persicae nicotianae densovirus, MpnDV) as model systems. MpnDV increased the activities of its host, promoting population dispersal and leading to significant proliferation in tobacco plants by significantly enhancing the titer of the sesquiterpene (E)-β-farnesene (EβF) via up-regulation of expression levels of the MpFPPS1 gene. The proliferation and dispersal of MpnDV-positive individuals were faster than that of MpnDV-negative individuals in PVY-infected tobacco plants, which promoted the transmission of PVY. These results combined showed that an insect virus may facilitate the transmission of a plant virus by enhancing the locomotor activity and population proliferation of insect vectors. These findings provide novel opportunities for controlling insect vectors and plant viruses, which can be used in the development of novel management strategies.

Synergism of (E)-β-farnesene and Its Analogue to Insecticides against the Green Peach Aphid Myzus persicae.

With high aphid-repellent activity but low stability, (E)-β-farnesene (EβF), the major component of the aphid alarm pheromone, can be used as a synergist to insecticides. Some EβF analogues possess both good aphid-repellent activity and stability, but the synergistic effect and related mechanism are still unclear. Therefore, this study investigated the synergistic effect and underlying mechanism of the EβF and its analogue against the aphid Myzus persicae. The results indicated that EβF and the analogue showed significantly synergistic effects to different insecticides, with synergism ratios from 1.524 to 3.446. Mechanistic studies revealed that EβF and the analogue exhibited effective repellent activity, significantly upregulated target OBP genes by 161 to 731%, increased aphid mobility, and thereby enhanced contact with insecticides. This research suggests that the EβF analogue represents a novel synergist for insecticides, with the potential for further application in aphid control owing to its enhanced bioactivity and the possibility of reducing insecticide doses.

The Effects of Natural Insecticides on the Green Peach Aphid Myzus persicae (Sulzer) and Its Natural Enemies Propylea quatuordecimpunctata (L.) and Aphidius colemani Viereck.

Botanical insecticides and soaps are frequently proposed as environmentally safer alternatives to synthetic insecticides. However, the efficacy and selectivity of these products are often only partially supported by empirical evidence. Here, we tested the effectiveness of five botanical insecticides, belonging to different categories, on the green peach aphid Myzus persicae (Sulzer) and their selectivity towards two natural enemies, the ladybird beetle Propylea quatuordecimpunctata (L.) and the parasitoid Aphidius colemani (Dalman). White thyme essential oil (EO), sweet orange EO, crude garlic extract and Marseille soap were tested and compared with a pyrethrin-based commercial product. Both direct spray assays and residual contact assays on treated cabbage leaf disks were carried out. The tested products had low efficacy against aphids when compared to pyrethrins but were in general less detrimental to ladybird beetle larvae, meaning that if applied against other pests, they have a lower chance of harming this agent of aphid biocontrol. Some of the products (soap, orange EO) did, however, show direct exposure toxicity toward ladybird larvae, and thyme EO had extensive phytotoxic effects on cabbage leaves, possibly indirectly leading to higher mortality in ladybird adults. These results underline the necessity for case-by-case evaluations of botanical insecticides.

The interplay between temperature and an insecticide mixture modulates the stimulatory response of sublethally exposed Myzus persicae.

Temperature can interact with chemical pesticides and modulate their toxicity. Sublethal exposure to pesticides is known to trigger hormetic responses in pests. However, the simultaneous effects of temperature and sublethal exposure to single or mixture-based insecticides on the insects' stimulatory responses are not frequently considered in toxicological studies. Here we investigated the combined effects of temperature on the lethal and sublethal responses of the green peach aphid Myzus persicae after exposure to commercial formulations of a neonicotinoid (thiamethoxam) and a pyrethroid (lambda-cyhalothrin) and their mixture. Firstly, the concentration-response curves of the insecticides were determined under four temperatures (15 °C, 20 °C, 25 °C, and 28 °C) by the leaf dipping method. Subsequently, the sublethal concentrations C0, CL1, CL5, CL10, CL15, CL20, and CL30 were selected to assess sublethal effects on aphids' longevity and reproduction under the same temperatures. The results showed that the mixture of thiamethoxam + lambda-cyhalothrin caused greater toxicity to aphids compared to the formulations with each active ingredient alone and that the toxicity was higher at elevated temperatures. Furthermore, the exposure to low concentrations of the mixture (thiamethoxam + lambda-cyhalothrin) and the separated insecticides induced stimulatory responses in the longevity and fecundity of exposed aphid females, but the occurrence of such hormetic responses depended on the insecticide type, its sublethal concentration, and the temperature as well as their interactions.

Effects of Two Prey Species Combinations on Larval Development of the Predatory Ladybird Cheilomenes propinqua.

Feeding on mixed, alternating, or changing diets often favor insect development. With the aim to optimize mass rearing and use for the biological control of insect pests, we investigated the effects of various combinations of high-quality (the green peach aphid Myzus persicae) and low-quality (eggs of the grain moth Sitotroga cerealella) foods on the larval development of a predatory ladybird Cheilomenes propinqua. In the first experiment, eggs and aphids were mixed in different proportions; in the second experiment, larvae switched from feeding on aphids to feeding on eggs. Although the beneficial additive effect of mixed foods was detected in some treatments with limited diets, feeding on various combinations of eggs with aphids never resulted in higher survival, faster development, or a larger size of emerging adults than those observed for feeding on unlimited amounts of aphids. For the practice of biological control, we conclude that, if necessary (for example, in the case of temporary shortage or a lack of aphids in mass rearing facilities or in the case of preventing release of C. propinqua adults in greenhouses), C. propinqua larvae can be fed with grain moth eggs by replacing, mixing, or alternating with aphids, although this will inevitably result in a proportional decrease in pre-adult survival, rate of development, weight, and size of the emerging adults. On the other hand, even a minimal addition of aphids can have a substantial positive effect on larvae fed with grain moth eggs.

Small but strong: herbivory by sap-feeding insect reduces plant progeny growth but enhances direct and indirect anti-herbivore defenses.

The transmission of resistance traits to herbivores across subsequent generations is an important strategy employed by plants to enhance their fitness in environments with high herbivore pressure. However, our understanding of the impact of maternal herbivory on direct and indirect induced chemical defenses of progeny, as well as the associated costs, is currently limited to herbivory by leaf-chewing insects. In this study, we investigated the transgenerational effects of a sap-feeding insect, the green peach aphid Myzus persicae, on direct and indirect chemical defenses of bell pepper plants (Capsicum annuum), and whether the effects entail costs to plant growth. Aphid herbivory on parental plants led to a reduced number of seeds per fruit, which exhibited lower germination rates and produced smaller seedlings compared to those from non-infested parental plants. In contrast, the progeny of aphid-infested plants were less preferred as hosts by aphids and less suitable than the progeny of non-infested plants. This enhanced resistance in the progeny of aphid-infested plants coincided with elevated levels of both constitutive and herbivore-induced total phenolic compounds, compared to the progeny of non-infested plants. Furthermore, the progeny of aphid-infested plants emitted herbivore-induced plant volatiles (HIPVs) that were more attractive to the aphid parasitoid Aphidius platensis than those emitted by the progeny of non-infested plants. Our results indicate that herbivory by sap-feeding insect induces transgenerational resistance on progeny bell pepper plants, albeit at the expense of vegetative growth.

Serine proteinase inhibitors from Nicotiana benthamiana, a nonpreferred host plant, inhibit the growth of Myzus persicae (green peach aphid).

The green peach aphid (Myzus persicae) is a severe agricultural crop pest that has developed resistance to most current control methods, requiring the urgent development of novel strategies. Plant proteinase inhibitors (PINs) are small proteins that protect plants against pathogens and/or herbivores, likely by preventing efficient protein digestion. We identified 67 protease genes in the transcriptomes of three M. persicae lineages (USDA-Red, G002 and G006). Comparison of gene expression levels in aphid guts and whole aphids showed that several proteases, including a highly expressed serine protease, are significantly overexpressed in the guts. Furthermore, we identified three genes encoding serine protease inhibitors (SerPIN-II1, 2 and 3) in Nicotiana benthamiana, which is a nonpreferred host for M. persicae. Using virus-induced gene silencing (VIGS) with a tobacco rattle virus (TRV) vector and overexpression with a turnip mosaic virus (TuMV) vector, we demonstrated that N. benthamiana SerPIN-II1 and SerPIN-II2 cause reduced survival and growth, but do not affect aphid protein content. Likewise, SerPIN-II3 overexpression reduced survival and growth, and serpin-II3 knockout mutations, which we generated using CRISPR/Cas9, increased survival and growth. Protein content was significantly increased in aphids fed on SerPIN-II3 overexpressing plants, yet it was decreased in aphids fed on serpin-II3 mutants. Our results show that three PIN-IIs from N. benthamiana, a nonpreferred host plant, effectively inhibit M. persicae survival and growth, thereby representing a new resource for the development of aphid-resistant crop plants. © 2024 Society of Chemical Industry.

Multiple toxins and a protease contribute to the aphid-killing ability of Pseudomonas fluorescens PpR24.

Aphids are globally important pests causing damage to a broad range of crops. Due to insecticide resistance, there is an urgent need to develop alternative control strategies. In our previous work, we found Pseudomonas fluorescens PpR24 can orally infect and kill the insecticide-resistant green-peach aphid (Myzus persicae). However, the genetic basis of the insecticidal capability of PpR24 remains unclear. Genome sequencing of PpR24 confirmed the presence of various insecticidal toxins such as Tc (toxin complexes), Rhs (rearrangement hotspot) elements, and other insect-killing proteases. Upon aphids infection with PpR24, RNA-Seq analysis revealed 193 aphid genes were differentially expressed with down-regulation of 16 detoxification genes. In addition, 1325 PpR24 genes (542 were upregulated and 783 downregulated) were subject to differential expression, including genes responsible for secondary metabolite biosynthesis, the iron-restriction response, oxidative stress resistance, and virulence factors. Single and double deletion of candidate virulence genes encoding a secreted protease (AprX) and four toxin components (two TcA-like; one TcB-like; one TcC-like insecticidal toxins) showed that all five genes contribute significantly to aphid killing, particularly AprX. This comprehensive host-pathogen transcriptomic analysis provides novel insight into the molecular basis of bacteria-mediated aphid mortality and the potential of PpR24 as an effective biocontrol agent.

Substrate-borne vibrations produced during the interaction with natural enemies alter aphids probing behavior

The “ecology of fear”, i.e., physiological and behavioral alterations displayed by pests in response to predation risk, has recently been proposed as a sustainable alternative to chemicals for pest control. However, the development of such a strategy requires a detailed understanding of the signals and cues underlying the pest-antagonist interaction and eliciting the prey behavioral alteration. Here, we characterized the substrate-borne vibrations produced during the interaction between the green peach aphid Myzus persicae and its antagonists, the parasitoid wasp Aphidius colemani and the ladybug Adalia bipunctata. Thereafter, coupling the electrical penetration graph (EPG) with a stimulus controller, we evaluated whether the playback of the vibrations, alone and in combination with the alarm pheromone, impacted aphid probing behavior and interaction with the host plant. Aphids responded to vibrations exhibiting longer non-probing, shorter intracellular probes, i.e. the behavior through which the insect evaluates host plant quality, delay in accessing the phloem vessels and decrease of the frequency of phloem salivation events. In contrast, on plants treated with the alarm pheromone, insects displayed longer intracellular probes. We hypothesize that the alarm pheromone, signaling a distant threat, might induce a careful evaluation of the host plant in order to decide the magnitude of the reaction. On the other hand, vibrations might indicate a closely approaching threat pushing the aphid to rush the host evaluation process and the whole feeding process. The possible repercussion of the behavioral alterations observed on the dynamics of aphid-borne plant virus transmission is also discussed.

Effects of thiamethoxam on physiological and molecular responses to potato plant (Solanum tuberosum), green peach aphid (Myzus persicae), and parasitoid (Aphidius gifuensis).

To improve integrated pest management (IPM) performance it is essential to assess pesticide side effects on host plants, insect pests, and natural enemies. The green peach aphid (Myzus persicae Sulzer) is a major insect pest that attacks various crops. Aphidius gifuensis is an essential natural enemy of M. persicae that has been applied effectively in controlling M. persicae. Thiamethoxam is a neonicotinoid pesticide widely used against insect pests. The current study showed the effect of thiamethoxam against Solanum tuberosum, M. persicae, and A. gefiuensis and the physiological and molecular response of the plants, aphids, and parasitoids after thiamethoxam application. Thiamethoxam affected the physical parameters of S. tuberosum and generated a variety of sublethal effects on M. persicae and A. gefiuensis, including nymph development time, adult longevity, and fertility. Our results showed that different thiamethoxam concentrations [0.1, 0.5, and 0.9 μm active ingredient (a.i.)/L] on different time durations (2, 6, and 10 days) increased the antioxidant enzyme activities SOD, POD, and CAT of S. tuberosum, M. persicae, and A. gefiuensis significantly compared with the control. Our results also showed that different thiamethoxam concentrations (0.1, 0.5, and 0.9 μm a.i./L) on different time durations (2, 6, and 10 days) increased the expression of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), acetylcholinesterase (AChE), carboxylesterase (CarE) and glutathione-S-transferase (GST) genes of S. tuberosum, M. persicae, and A. gefiuensis compared with the control. Our findings reveal that using thiamethoxam at suitable concentrations and time durations for host plants and natural enemies may enhance natural control through the conservation of natural enemies by overcoming any fitness disadvantages. © 2024 Society of Chemical Industry.

Resistance to both aphids and nematodes in tobacco plants expressing a Bacillus thuringiensis crystal protein.

Bacillus thuringiensis (Bt) and its crystal toxin or δ-endotoxins (Cry) offer great potential for the efficient control of crop pests. A vast number of pests can potentially infect the same host plant, either simultaneously or sequentially. However, no effective Bt-Cry protein has been reported to control both aphids and plant parasitic nematodes due to its highly specific activity. Our study indicated that the Cry5Ba2 protein was toxic to the green peach aphid Myzus persicae, which had a median lethal concentration (LC50) of 9.7 ng μL-1 and fiducial limits of 3.1-34.6 ng μL-1. Immunohistochemical localization of Cry5Ba2 revealed that it could bind to the apical tip of microvilli in midgut regions. Moreover, transgenic tobacco plants expressing Cry5Ba2 exhibited significant resistance to Myzus persicae, as evidenced by reduced insect survival and impaired fecundity, and also intoxicated the Meloidogyne incognita as indicated by a decrease in galls and progeny reproduction. In sum, we identified a new aphicidal Bt toxin resource that could simultaneously control both aboveground and belowground pests, thus extending the application range of Bt-based strategy for crop protection. © 2024 Society of Chemical Industry.