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13 pages, 3237 KiB

Open AccessArticle

Effect of Three Novel Thiazolidiones on the Development, Reproduction, and Trehalase Activity of Spodoptera frugiperda (Lepidoptera: Noctuidae)

by Liuhe Yu, Fan Zhong, Xinyi Jiang, Biner He, Haoyu Fu, Xiangyu Liu, Qixuan Mao, Ying Zhao, Shigui Wang, Yan Wu, Hongxia Duan and Bin Tang

Agronomy 2024, 14(6), 1315; https://doi.org/10.3390/agronomy14061315 - 18 Jun 2024

Viewed by 706

Abstract

Spodoptera frugiperda was used to investigate its role as a trehalase inhibitor of three new thiothiazolidone compounds—6d, 6e, and 6f. The development and reproduction of S. frugiperda were investigated to evaluate the potential of these compounds as a novel [...] Read more.

Spodoptera frugiperda was used to investigate its role as a trehalase inhibitor of three new thiothiazolidone compounds—6d, 6e, and 6f. The development and reproduction of S. frugiperda were investigated to evaluate the potential of these compounds as a novel pesticide for pest control. Compounds 6d, 6e, and 6f were injected into larvae and female pupae. Molecular changes in trehalose and chitin metabolism genes were monitored. Pupal trehalase activity, the female pupal emergence rate, ovarian development, and SfVg and SfVgR gene expression levels were assessed. The results revealed that all three compounds significantly inhibited trehalase activity in the larvae. The expression of TRE was significantly downregulated, and compounds 6d and 6f significantly downregulated the expression of TRE2. Treated larvae exhibited significantly decreased survival rates and a higher incidence of abnormalities. The egg production and hatching rates were markedly diminished by the inhibitors, and the ovaries displayed blackening and clumping. These compounds exhibit promise as eco-friendly insecticides, but further experiments are required to test their multifaceted capabilities. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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12 pages, 1624 KiB

Open AccessArticle

Rice Stripe Virus Infection Facilitates the Reproductive Potential of Laodelphax striatellus

by Yuanyuan Zhang, Youxin Yu, Meiqi Xu, Jingyan Liao, Chenjia Shao, Liran Fu, Mingshi Qian, Gang Xu and Guoqing Yang

Agronomy 2024, 14(4), 714; https://doi.org/10.3390/agronomy14040714 - 29 Mar 2024

Cited by 1 | Viewed by 1228

Abstract

The rice stripe virus (RSV) is transmitted by the small brown planthopper Laodelphax striatellus in a persistent and circulative–propagative manner. During the last few decades, RSV has caused serious disease outbreaks in rice fields in China. The results of long-term coevolution have led [...] Read more.

The rice stripe virus (RSV) is transmitted by the small brown planthopper Laodelphax striatellus in a persistent and circulative–propagative manner. During the last few decades, RSV has caused serious disease outbreaks in rice fields in China. The results of long-term coevolution have led to complex and diverse relationships between viruses and vector insects, and understanding these interactions is critical for the management of diseases and vector organisms. In this study, three groups of comparative experiments were performed to investigate the effects of RSV infection on the reproductive parameters, vitellogenin (Vg), and Vg receptor (VgR) expressions of L. striatellus. The results showed that RSV infection promoted the fecundity, hatchability, and Vg and VgR expressions of L. striatellus but had no effect on the preoviposition period and oviposition period. Furthermore, the RNA interference of the nucleocapsid protein (CP) gene and the injection of the CP antibody in RSV-viruliferous L. striatellus reduced the fecundity, hatchability, and Vg and VgR expressions, further strengthening the hypothesis that RSV may manipulate the reproductive behavior of insect vectors to promote its own transmission. The results of this study can further reveal the interaction mechanism of virus–vector insects in reproduction and virus transmission, and provide new insights for the control of insect-borne viruses. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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18 pages, 3680 KiB

Open AccessArticle

Cadmium Exposure Impairs Development, Detoxification Mechanisms and Gene Expression of Glyphodes pyloalis Walker (Lepidoptera: Pyralidae)

by Shuaiqi Zhao, Wanglong Miao, Sheng Sheng, Xin Pan, Ping Li, Weihong Zhou and Fuan Wu

Agronomy 2024, 14(3), 626; https://doi.org/10.3390/agronomy14030626 - 20 Mar 2024

Cited by 2 | Viewed by 1156

Abstract

Cadmium (Cd) is the most serious heavy metal pollutant in the agricultural soil of China and can transfer and accumulate through the food chain and affect the growth, development and physiological processes of phytophagous insect. Glyphodes pyloalis Walker (G. pyloalis) is [...] Read more.

Cadmium (Cd) is the most serious heavy metal pollutant in the agricultural soil of China and can transfer and accumulate through the food chain and affect the growth, development and physiological processes of phytophagous insect. Glyphodes pyloalis Walker (G. pyloalis) is one of the most important pests of mulberry, and there are few studies on the adverse effects of heavy metals on insects, especially mulberry pests. To understand the toxicology of Cd exposure on G. pyloalis, we investigated the effects of three different concentrations of Cd (0, 3.89 and 51.69 mg/kg, labeled as control check (CK), low dose (LD) and high dose (HD)) on the development and detoxification mechanism of G. pyloalis and explored the molecular mechanism of Cd on G. pyloalis larvae using RNA-seq technology. Transcriptome analysis showed that compared with the CK, a total of 63 differentially expressed genes (DEGs) were identified in LD exposure, including 24 upregulated and 39 downregulated candidates. In CK versus HD groups, 395 upregulated DEGs and 436 downregulated DEGs were identified and the expression patterns of 12 genes related to detoxification and metabolism were verified using qPCR. These DEGs were relevant to multiple specific peroxisome and drug metabolism-cytochrome P450 pathways. Gene annotation and quantitative real-time PCR revealed that a high concentration of Cd significantly stimulated the expression of metabolic detoxification enzyme genes. The results revealed that Cd exposure changed the pupal weight, adult emergence rate and the activities of AKP, ACP and GST in G. pyloalis and induced notable adverse effects at the molecular level on detoxification and metabolism such as concentration and time differences. In addition, we silenced CYP12A2 by RNA interference. Bioassays showed that after silencing CYP12A2, the survival rate of G. pyloalis under Cd exposure was lower than that of the control group. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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12 pages, 1893 KiB

Open AccessArticle

Change in the Physiological Aspects of Soybean Caused by Infestation by Bemisia tabaci MEAM1

by Luciana B. Silva, Lucas C. Almeida, Maria C. F. e Silva, Ramilos R. de Brito, Rafael de S. Miranda, Raimundo H. F. Rodrigues, Carlos M. P. dos Santos, Gilvana da S. Ribeiro, João V. S. Morais, Alisson F. T. da Silva, Hernesise Mayard, Thayline Rodrigues de Oliveira, Vânia Maria Gomes da Costa Lima, Lucia da Silva Fontes, Neurandir Sobrinho da Rocha, Julian de Jesus Lacerda and Bruno Ettore Pavan

Agronomy 2024, 14(3), 481; https://doi.org/10.3390/agronomy14030481 - 28 Feb 2024

Viewed by 1429

Abstract

Whiteflies cause significant crop losses through direct sap feeding, inducing plant physiological disorders and promoting the growth of sooty mold. Moreover, whiteflies can indirectly harm plants by transmitting plant viruses, particularly begomoviruses and criniviruses, resulting in severe viral disease epidemics. This study aimed [...] Read more.

Whiteflies cause significant crop losses through direct sap feeding, inducing plant physiological disorders and promoting the growth of sooty mold. Moreover, whiteflies can indirectly harm plants by transmitting plant viruses, particularly begomoviruses and criniviruses, resulting in severe viral disease epidemics. This study aimed to evaluate the physiological characteristics of susceptible and resistant soybean cultivars to B. tabaci. The experiments were conducted in a greenhouse. Eleven soybean cultivars were selected and infested with 100 adults of B. tabaci at the V3 stage. The evaluation of photosynthetic parameters, such as photosynthetic rate, leaf transpiration, stomatal conductance, and internal CO₂ concentration, revealed that B. tabaci infestation influenced gas exchange in soybean plants. The photosynthetic rate was higher in cultivars AS3810 and M8349 during the V6 stage. Infestations caused alterations in photosynthetic parameters, suggesting increased energy demand to maintain photosynthetic activity. However, the response to infestation varied among the different cultivars, indicating varying levels of resistance and tolerance to the whitefly’s damage. Furthermore, the infestation had a more notable impact during the vegetative phenological stage. In summary, infestation by B. tabaci has a discernible impact on the physiology of soybean plants, resulting in alterations in gas exchange parameters and water use efficiency. The reaction to infestation exhibited variations among different soybean cultivars, indicating potential differences in resistance to the pest. This study underscores the significance of assessing the physiological consequences of whitefly infestations on soybean crops. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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17 pages, 2333 KiB

Open AccessEditor’s ChoiceArticle

Life Parameters and Physiological Reactions of Cotton Aphids Aphis gossypii (Hemiptera: Aphididae) to Sublethal Concentrations of Afidopyropen

by Wenjuan Ding, Longzhi Guo, Yannan Xue, Mei Wang, Chuanwang Li, Ruikai Zhang, Siwen Zhang and Xiaoming Xia

Agronomy 2024, 14(2), 258; https://doi.org/10.3390/agronomy14020258 - 25 Jan 2024

Cited by 4 | Viewed by 1485

Abstract

The massive and repetitive application of synthetic insecticides for the management of cotton pests results in the accumulation of resistance in Aphis gossypii Glover, a destructive pest worldwide. New chemistries are needed for pest management. Afidopyropen exhibits high efficacy against piercing-sucking pests and [...] Read more.

The massive and repetitive application of synthetic insecticides for the management of cotton pests results in the accumulation of resistance in Aphis gossypii Glover, a destructive pest worldwide. New chemistries are needed for pest management. Afidopyropen exhibits high efficacy against piercing-sucking pests and has been applied as a complementary alternative insecticide against aphids. This study was conducted to investigate the lethal and sublethal effects of afidopyropen on the life parameters and physiological responses of A. gossypii. Detoxifying enzyme activities and expression levels of P450 genes were compared after exposure to three generations of afidopyropen. Bioassay results indicate that afidopyropen possessed the highest toxicity, with a LC₅₀ value of 0.30 mg/L. Sublethal concentrations (LC₅ and LC₁₀) caused adverse impacts on the F0 generation, reducing adult longevity and fecundity. A high concentration (LC₁₀) also caused adverse effects on the F1 generation, while a low concentration (LC₅) stimulated the fecundity. After continuous treatments with afidopyropen, the susceptibility decreased. GSTs and P450 were induced through sublethal concentrations; moreover, their activities in the F3 generation were higher than that in the F0 generation. Furthermore, the expression levels of 12 P450 genes in the F3 generation were higher than those in F0 generation. In conclusion, afidopyropen has excellent acute toxicity and continuous control effects on A. gossypii. GSTs and P450 may play important roles in the resistance of A. gossypii to afidopyropen. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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14 pages, 3515 KiB

Open AccessArticle

Genome-Wide Identification of the Genes of the Odorant-Binding Protein Family Reveal Their Role in the Olfactory Response of the Tomato Leaf Miner (Tuta absoluta) to a Repellent Plant

by Ruixin Ma, Donggui Li, Chen Peng, Shuangyan Wang, Yaping Chen, Furong Gui and Zhongxiang Sun

Agronomy 2024, 14(1), 231; https://doi.org/10.3390/agronomy14010231 - 22 Jan 2024

Viewed by 2269

Abstract

The remarkable biological and evolutionary adaptations of insects to plants are largely attributed to the powerful chemosensory systems of insects. The tomato leaf miner (Tuta absoluta) is a destructive invasive pest with a global distribution that poses a serious threat to [...] Read more.

The remarkable biological and evolutionary adaptations of insects to plants are largely attributed to the powerful chemosensory systems of insects. The tomato leaf miner (Tuta absoluta) is a destructive invasive pest with a global distribution that poses a serious threat to the production of nightshade crops, especially tomatoes. Functional plants can attract or repel insect pests by releasing volatiles that interact with the olfactory system of insects, thereby reducing the damage of insect pests to target crops. However, there is limited research on the interaction between T. absoluta olfactory genes and functional plants. In this study, 97 members of the putative odorant-binding protein (OBP) family have been identified in the whole genome of T. absoluta. Phylogenetic analysis involving various Lepidopteran and Dipteran species, including D. melanogaster, revealed that OBP gene families present conserved clustering patterns. Furthermore, the Plus-C subfamily of OBP showed extremely significant expansion. Moreover, the expression levels of the OBP genes varied significantly between different developmental stages; that is, the highest number of OBP genes were expressed in the adult stage, followed by the larval stage, and fewer genes were expressed in high abundance in the egg stage. On the other hand, through a Y-tube olfactometer, we identified a functional plant—Plectranthus tomentosa—that significantly repels adult and larval T. absoluta. Finally, we screened the OBP genes in response to tomato and P. tomentosa volatiles at the genomic level of T. absoluta using RT-qPCR. These results laid a good foundation for controlling T. absoluta with functional plants and further studying olfactory genes. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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13 pages, 2295 KiB

Open AccessArticle

Characterization of the TcCYPE2 Gene and Its Role in Regulating Trehalose Metabolism in Response to High CO₂ Stress

by Yan-Fei Zhou, Min Zhou, Yuan-Yuan Wang, Xin-Yi Jiang, Pei Zhang, Kang-Kang Xu, Bin Tang and Can Li

Agronomy 2023, 13(9), 2263; https://doi.org/10.3390/agronomy13092263 - 28 Aug 2023

Cited by 1 | Viewed by 1253

Abstract

Cytochrome P450 monooxygenase (CYP) is one of the three detoxification metabolic enzymes in insects, and is involved in the metabolism and transformation of endogenous substances as well as the activation and degradation of exogenous compounds. This study aims to reveal the molecular mechanism [...] Read more.

Cytochrome P450 monooxygenase (CYP) is one of the three detoxification metabolic enzymes in insects, and is involved in the metabolism and transformation of endogenous substances as well as the activation and degradation of exogenous compounds. This study aims to reveal the molecular mechanism of CYP9E2 in Tribolium castaneum in adapting to high-CO₂ stress. By predicting the sequence function of CYP9E2, analyzing the temporal and spatial expression profile of TcCYP9E2, and using RNAi to silence TcCYP9E2 combined with a high-CO₂ stress treatment, we measured the carbohydrate content, trehalase activity, and gene expression levels in trehalose metabolism of T. castaneum. A bioinformatics analysis showed that the predicted molecular weight of the protein encoded by TcCYP9E2 is 60.15, the theoretical isoelectric point is 8.63, there is no signal peptide, and the protein is hydrophilic. An evolutionary tree analysis showed that TcCYP9E2 belongs to the CYP6 family and belongs to the CYP3 group; and the spatiotemporal expression profile results showed that TcCYP9E2 was highly expressed in the larvae midgut 48 h after injection of dsCYP9E2, with survival rates decreasing with the increase in CO₂ concentration. Under the condition of 75% CO₂, the contents of glycogen, glucose, ATP, and membrane-bound trehalase decreased significantly after the injection of dsCYP9E2. The expression of TRE-1, TRE-2, and GP in trehalose metabolism and energy pathways was significantly downregulated. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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17 pages, 2107 KiB

Open AccessArticle

Host-Plant Switching Impacts Susceptibility and Biochemical Responses of Cnaphalocrocis medinalis to Abamectin and Chlorpyrifos

by Jiawen Guo, Yisha Cheng, Xiaoyu Zhao, Jianing Qian, Zhongxian Lu, Yanhui Lu, Yihao Dan, Hongxing Xu and Yan Wu

Agronomy 2023, 13(5), 1245; https://doi.org/10.3390/agronomy13051245 - 27 Apr 2023

Cited by 1 | Viewed by 1569

Abstract

Insect tolerance to insecticides is closely related to the host plant. Migratory insects flying downwind and landing randomly may face host-plant switching after migration. However, it is not clear whether host-plant switching affects the tolerance of migratory insects to insecticides. In the present [...] Read more.

Insect tolerance to insecticides is closely related to the host plant. Migratory insects flying downwind and landing randomly may face host-plant switching after migration. However, it is not clear whether host-plant switching affects the tolerance of migratory insects to insecticides. In the present work, Cnaphalocrocis medinalis, a migratory pest destructive to rice, was studied to explore this issue. The results show that the host-plant switch reduced the susceptibility of rice and wheat larvae populations to abamectin but increased that of wheat larvae populations to chlorpyrifos, indicating that host switching resulted in different tolerance to different insecticides. Enzyme activity determination showed that, although abamectin and chlorpyrifos affect the activities of detoxification enzymes (carboxylesterase, multifunctional oxidase, and glutathione S-transferases), antioxidant enzymes (superoxide dismutase, peroxidase, and catalase), and acetylcholinesterase at sublethal dosages, the effect depends on the host plant and insecticide species. Overall, our findings show that the induction of C. medinalis by host switching affects its susceptibility and biochemical responses to abamectin and chlorpyrifos. Insecticides against C. medinalis should be used with consideration of the potential impact of host switching. Reasonable selection and usages of insecticides can help in the resistance management and control of migratory insects. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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13 pages, 2201 KiB

Open AccessArticle

Complex Cd–Pb Multigenerational Exposure Improves the Growth and Food Utilization of the Cutworm Spodoptera litura

by Meifang Zhang, Jin Chen, Kaixuan Wu, Shiru Chen, Jianwu Wang and Yinghua Shu

Agronomy 2023, 13(5), 1207; https://doi.org/10.3390/agronomy13051207 - 25 Apr 2023

Cited by 3 | Viewed by 1624

Abstract

Concurrent exposure to cadmium (Cd) and lead (Pb) is prevalent in the environment, but information on the long-term impacts of complex Cd–Pb exposure on herbivorous insects, especially at low doses, is scant. We studied the effects of complex Cd–Pb exposure (4.06 mg/kg Cd [...] Read more.

Concurrent exposure to cadmium (Cd) and lead (Pb) is prevalent in the environment, but information on the long-term impacts of complex Cd–Pb exposure on herbivorous insects, especially at low doses, is scant. We studied the effects of complex Cd–Pb exposure (4.06 mg/kg Cd and 12.5 mg/kg Pb) on the growth and food utilization of the herbivorous insect Spodoptera litura for 10 continuous generations. Cd or Pb ingestion, excretion and accumulation by insect at the different developmental stages was determined for ten generations. The weighted scores calculated by the analytic hierarchy process (AHP) on the basis of the parameters of survival, growth and food utilization indicated that complex Cd–Pb exposure had positive impacts on the insects, regardless of generations. Compared with Cd (4.06 mg/kg Cd) and Pb (12.5 mg/kg Pb) alone, complex Cd–Pb exposure showed antagonistic interactions. After exposure to complex Cd–Pb, although larvae significantly increased heavy metal uptake along with the elevated ECD and ECI, insects enhanced heavy metal excretion via the feces and puparium; consequently, heavy metal accumulation in the insect body significantly decreased. With increasing generations, the positive impacts of complex Cd–Pb stress on insects became increasingly obvious, and the uptake of Cd or Pb decreased while the excretion of Cd or Pb increased, which demonstrated that insect tolerance to Cd–Pb exposure at low concentrations increased over generations. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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16 pages, 2249 KiB

Open AccessArticle

Different Maize Ear Rot Fungi Deter the Oviposition of Yellow Peach Moth (Conogethes punctiferalis (Guenée)) by Maize Volatile Organic Compounds

by Yinhu Chen, Jie Han, Haiqing Yang, Xiaochun Qin, Honggang Guo and Yanli Du

Agronomy 2023, 13(1), 251; https://doi.org/10.3390/agronomy13010251 - 14 Jan 2023

Cited by 2 | Viewed by 2127

Abstract

Yellow peach moth (Conogethes punctiferalis (Guenée), (Lepidoptera: Crambidae), YPM) and maize ear rot are important pests and diseases of maize (Zea mays L., (Poales: Poaceae)). In recent years, YPM has become the most destructive maize pest in the Huang-Huai-Hai summer maize [...] Read more.

Yellow peach moth (Conogethes punctiferalis (Guenée), (Lepidoptera: Crambidae), YPM) and maize ear rot are important pests and diseases of maize (Zea mays L., (Poales: Poaceae)). In recent years, YPM has become the most destructive maize pest in the Huang-Huai-Hai summer maize region of China via the tunneling of larvae into maize ears. Interestingly, YPM infestation aggravates the occurrence of maize ear rot and causes heavier yield loss of maize in the field. However, few studies report whether maize ear rot would also affect the behavior of YPM. Here, we identified the effects of maize ear rot caused by four different fungi on maize ears’ volatile organic compounds (VOCs) and the cascading effects on the behavior of YPM. The current results found that mated YPM females showed a preference for mock-inoculated maize ears (MIM) or mechanically damaged maize ears (MDM) but showed repellence to Penicillium oxalicum (Eurotiales: Aspergillaceae)-infected maize ears (POM), Trichoderma asperellum (Hypocreales: Hypocreaceae)-infected maize ears (TAM), Aspergillus phoenicis (Eurotiales: Aspergillaceae)-infected maize ears (APM), Aspergillus flavus (Eurotiales: Aspergillaceae)-infected maize ears (AFM) in the oviposition selection and four-arm olfactometer experiments, indicating that VOCs emitting from fungi-infected maize ears were all repellent to mated YPM females. Further analyses showed that 57 VOCs were identified from all treatments. The partial least squares discriminant analysis (PLS-DA) displayed a separation between TAM, APM, AFM and POM, MDM, and MIM, with 24.3% and 19.1% explanation rates of the first two PLS components. Moreover, the relative quantities of eight common VOCs from different treatments were lower, and the other three common VOCs were higher in fungi-infected maize ears than those in MIM or MDM. There were also 17 unique VOCs in fungi-infected maize ears. In conclusion, these results suggested that maize ear rot negatively affected the behavior of YPM by changing both components and proportions of maize ears’ VOCs. These behavior-modifying VOCs may form the basis for the development of attractant or repellent formulations for YPM’s management in the future. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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18 pages, 2884 KiB

Open AccessArticle

Regulatory Role of Trehalose Metabolism in Cold Stress of Harmonia axyridis Laboratory and Overwinter Populations

by Sijing Wan, Jianyun He, Lei Chao, Zuokun Shi, Shasha Wang, Weidong Yu, Zhen Huang, Su Wang, Shigui Wang and Zhijun Zhang

Agronomy 2023, 13(1), 148; https://doi.org/10.3390/agronomy13010148 - 2 Jan 2023

Cited by 5 | Viewed by 2076

Abstract

Trehalose is a non-reducing disaccharide that plays a key role in the response to cold and other environmental stressors in insects. Harmonia axyridis (Pallas) is an important natural predator of insect pests and has become a cosmopolitan invasive species, causing negative ecological impacts [...] Read more.

Trehalose is a non-reducing disaccharide that plays a key role in the response to cold and other environmental stressors in insects. Harmonia axyridis (Pallas) is an important natural predator of insect pests and has become a cosmopolitan invasive species, causing negative ecological impacts worldwide. In this study, the relative survival ability, trehalose and glycogen contents, trehalose activity and trehalose metabolism-related gene-expression profiles over a cold storage period were compared in a natural overwintering population and an indoor laboratory (experimental) population. Yellow adults were dominant in the overwintering population. The survival rate of the overwintering population during the cold storage period was higher than that of the experimental population after the fifth day. The contents of trehalose and glycogen in the overwinter population were higher than those of the experimental population during cold storage. Trehalose and glycogen contents initially increased and then decreased in the overwinter population, but decreased consistently over the cold storage period in the experimental population. Nevertheless, trehalose levels were relatively higher during the cold storage period in the overwinter population, with higher expression of TPS and TRE and trehalase activity. More importantly, the experiment showed that yellow adults have a better ability to regulate trehalose metabolism under cold storage compared to black adults. A strong resilience against cold stress and long-term cold storage ability could contribute to a better understanding of the invasiveness of H. axyridris. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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12 pages, 3234 KiB

Open AccessArticle

Zinc Stress Alters Sugar Content in Rice Plants and the Reproduction and Trehalose Metabolism in Nilaparvata lugens

by Yong-Kang Liu, Cai-Di Xu, Xu-Song Zheng, Lei Chao, Yan-Fei Zhou, Guo-Yong Li, Yan Wu, Xue-Lian Bai, Ting Zhou, Bin Tang and Hong-Xing Xu

Agronomy 2023, 13(1), 73; https://doi.org/10.3390/agronomy13010073 - 26 Dec 2022

Cited by 2 | Viewed by 1974

Abstract

Excessive zinc (Zn) is toxic to plants, but the effect of zinc-stressed plants on herbivorous insects is still unclear. Hence, we assessed the effect of zinc-stressed rice plants on its feeding pest, Nilaparvata lugens. The soil–rice–N. lugens system was treated with [...] Read more.

Excessive zinc (Zn) is toxic to plants, but the effect of zinc-stressed plants on herbivorous insects is still unclear. Hence, we assessed the effect of zinc-stressed rice plants on its feeding pest, Nilaparvata lugens. The soil–rice–N. lugens system was treated with Zn²⁺ solution. Sugar content in rice was measured, and the reproduction and trehalose metabolism in N. lugens were assessed. The trehalase activity in rice significantly decreased at 100 mg·kg⁻¹ Zn²⁺, and the trehalose content increased. The glucose and starch content increased at higher Zn²⁺ concentrations. The fecundity and trehalose content of N. lugens decreased after feeding on zinc-stressed rice, and the glucose content in the high Zn²⁺ group was significantly higher than that in the low Zn²⁺ group. In addition, the soluble trehalase activity of N. lugens significantly decreased under the 125 mg·kg⁻¹ treatment, while the activity of membrane-bound trehalase significantly increased under the 150 mg·kg⁻¹ treatment. Quantitative RT-PCR indicated significantly lower expressions of NlTre1-1, NlTre2, and NITps after Zn treatment. In conclusion, Zn²⁺ treatment significantly altered the sugar content in rice plants; it also decreased the fecundity of N. lugens, which may be mediated by alterations in trehalose metabolism. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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19 pages, 3596 KiB

Open AccessArticle

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

by Youxin Yu, Yuanyuan Zhang, Mingshi Qian, Qiuxin Zhang, Guoqing Yang and Gang Xu

Agronomy 2022, 12(12), 3202; https://doi.org/10.3390/agronomy12123202 - 16 Dec 2022

Cited by 4 | Viewed by 1716

Abstract

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 [...] Read more.

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. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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12 pages, 2597 KiB

Open AccessArticle

Characterizing the Mechanism of Serotonin Alleviates Rice Resistance to Brown Planthopper Nilaparvata lugens (Homoptera: Delphacidae) Nymphs

by Lin Chen, Ling Feng, Xinyan Liang, Jitong Li, Guangrong Liao, Lei Zhu, Kang Fu, Wenyan Fan, Shuang Wang and Jinglan Liu

Agronomy 2022, 12(12), 3191; https://doi.org/10.3390/agronomy12123191 - 16 Dec 2022

Cited by 2 | Viewed by 2185

Abstract

Serotonin is a well-known secondary metabolite that plays an important role in many growth and developmental processes, as well as biotic and abiotic stress responses of plants. Yet, whether serotonin biosynthesis regulates the resistance of rice to the brown planthopper (BPH) Nilaparvata lugens [...] Read more.

Serotonin is a well-known secondary metabolite that plays an important role in many growth and developmental processes, as well as biotic and abiotic stress responses of plants. Yet, whether serotonin biosynthesis regulates the resistance of rice to the brown planthopper (BPH) Nilaparvata lugens and its underling mechanisms have not been entirely investigated. In this study, we found that expression levels of four serotonin biosynthesis gene, OsTDC1, OsTDC2, OsTDC3, and OsT5H, and the serotonin content were significantly induced by BPH nymph infestation. The rice seedlings pretreated with serotonin were more attractive to BPH nymphs and promoted their feeding behavior as indicated by increased honeydew excretion. In addition, serotonin application to artificial diets increased the survival rates of BPH nymphs in a dose-dependent manner compared to the controls. Moreover, the exogenous serotonin application to rice seedlings increased the average injury scale and functional plant loss indices caused by BPH nymph infestation. Moreover, supplemented serotonin enhanced soluble sugar and free amino acid contents, as well as the activities of SOD, POD, and PPO, but repressed the production of flavonoids. Our findings illustrated that serotonin plays a negative role in the regulation of rice resistance to BPH nymphs probably by modulating contents of soluble sugars, free amino acids, and flavonoids. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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14 pages, 1083 KiB

Open AccessArticle

Effect of Carbohydrate Nutrition on Egg Load and Population Parameters of Four Trichogramma Species

by Yong Wang, Asim Iqbal, Ming-Yue Mu, Zhuo-Yi Zang, Yang-Yang Hou and Lian-Sheng Zang

Agronomy 2022, 12(12), 3143; https://doi.org/10.3390/agronomy12123143 - 10 Dec 2022

Cited by 3 | Viewed by 1783

Abstract

Trichogramma parasitoids are the most widely used biocontrol agents and play a crucial role in the biological control of agricultural and forest pests. Many studies have shown that Trichogramma parasitoids feeding on carbohydrate rich diet can effectively improve their egg laying capacity and [...] Read more.

Trichogramma parasitoids are the most widely used biocontrol agents and play a crucial role in the biological control of agricultural and forest pests. Many studies have shown that Trichogramma parasitoids feeding on carbohydrate rich diet can effectively improve their egg laying capacity and longevity. However, few studies have reported the impact of carbohydrate-rich diet on the biological parameters of different species of Trichogramma parasitoids. In this study, we compared the differences between the biological parameters of four Trichogramma species (T. dendrolimi, T. chilonis, T. leucaniae and T. ostriniae) before and after feeding on carbohydrate-rich diet. The results showed that all the biological parameters of Trichogramma species improved after feed on carbohydrate-rich diet. After eclosion, T. dendrolimi had the highest egg load (51.89 eggs) followed by T. chilonis (26.86 eggs), T. ostriniae (24.71 eggs), and T. leucaniae (12.44 eggs). Trichogramma dendrolimi showed an increased trend in egg load (66.7–86.21 eggs) after feeding on carbohydrate-rich diet, followed by T. chilonis (33.12–45.56 eggs), as compared to the other three species. Furthermore, T. leucaniae and T. ostriniae benefited much less from the ingestion of carbohydrate-rich diet, as only accelerated egg maturation in T. ostriniae was observed. Most of the egg loads consisted of matured eggs, so the trend of mature eggs was the same as that of the egg load. We also tested the population parameters of the Trichogramma species using the TWOSEX-MSChart. The results showed that the Trichogramma species fed with a honey diet had higher fecundities, i.e., T. dendrolimi (146.64), T. chilonis (173.53), T. leucaniae (83.69), and T. ostriniae (80.45), than when fed with water, i.e., 78.49, 40.15, 32.45 and 35.47, respectively. T. dendrolimi and T. chilonis had a higher intrinsic rate of increase r (0.4178 d⁻¹, 0.3933 d⁻¹), finite rate of increase λ (1.5186 d⁻¹, 1.4818 d⁻¹), and net reproductive rate R₀ (130 offspring, 147.4 offspring), than T. leucaniae and T. ostriniae (r = 0.3373 d⁻¹, 0.3317 d⁻¹; λ = 1.4011 d⁻¹, 1.3934 d⁻¹; R₀ = 73.2 offspring, 68.1 offspring) after feeding on a honey diet. We conclude that carbohydrate-rich diet significantly enhanced the biological control efficacy of Trichogramma, but the performance differed among different species. The results of this study contribute to improving the efficient application of Trichogramma parasitoids in the field. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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12 pages, 1679 KiB

Open AccessArticle

Short-Term Temperature Stress Modulates Fitness Traits in Bactrocera zonata, through Negative Impact on Larval Stage

by Farman Ullah, Ihsan ul Haq, Hina Gul, Ali Güncan, Muhammad Hafeez, Kaleem Tariq, Nicolas Desneux and Zhihong Li

Agronomy 2022, 12(11), 2903; https://doi.org/10.3390/agronomy12112903 - 21 Nov 2022

Cited by 3 | Viewed by 1994

Abstract

The frequency and magnitude of climate extremes, especially temperature extremes (TE), are increasing, which are exposing insect populations. However, insect responses to TE are poorly understood. In this study, we investigated the impact of high-temperature (HT: 38 °C) and low-temperature (LT: 3 °C) [...] Read more.

The frequency and magnitude of climate extremes, especially temperature extremes (TE), are increasing, which are exposing insect populations. However, insect responses to TE are poorly understood. In this study, we investigated the impact of high-temperature (HT: 38 °C) and low-temperature (LT: 3 °C) stresses on demographic parameters and population projections of the peach fruit fly, Bactrocera zonata, a destructive pest of fruits and vegetables. Results show that the larval developmental stage was significantly increased by HT (8.30 d) and LT (8.10 d) compared with control (7.02 d). The preadult stage in the HT and LT stressed flies were 18.56 d and 18.40 d, respectively compared with control (17.37 d). Mean longevities of both males and females were also substantially prolonged in HT and LT treatments. Compared with control, the total pre-oviposition period (TPOP) and oviposition days of B. zonata were significantly increased in both stress conditions. Furthermore, female fecundity of flies significantly increased in both HT and LT (705.48 and 698.38 respectively) treatments compared with control (578.35). These findings show that temperature stresses in the larval stage delayed the larval development and increase the reproduction and life span of B. zonata. The temperature induces alteration in life-history traits that might have significant agricultural impacts on the control strategies for this key pest. Full article

(This article belongs to the Special Issue Adaptation and Responses of Insects under Abiotic, Biotic and Xenobiotic Constraints)

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