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  • Monthly, Founded in 1950
    Supervisor:Chinese Academy of Sciences
    Sponsor:Institute of Zoology,Chinese Academy of Sciences
    The Entomological Society of China
    Domestic postal code: 2-153
    Foreign issuance code: Q61
    ISSN 0454-6296
    CN 11-1832/Q
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 Photo shows an adult of the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae) on a leaf of Brassica chinensis . In this issue, the effects of gut bacteria on the Bt susceptibility in P. xylostella, by competing for niche and protecting the inner wall of gut (pp.1645-1657) and the effects of multiple mating on the spermatophore formation and fecundity of P. xylostella  [Detail] ...
Current Issue
20 December 2022, Volume 65 Issue 12
INTRODUCTION
Insect development and immunity: An important branch of modern entomology
WANG Mao, ZOU Zhen, XU Wei-Hua
2022, 65(12):  1565-1570.  doi:10.16380/j.kcxb.2022.12.001
Abstract ( 54 )   PDF (1235KB) ( 22 )   PDF(mobile) (1235KB) ( 7 )     
 As one of the important branches of entomology, insect development and immunity, facing the national demand and scientific frontier, has made great achievements in solving major pest disasters and human health through multidimensional research. Meanwhile, the progress of new biotechnology has greatly promoted the research of insect development and immunity by deepening and widening our understanding of insect development and immune defense. Articles in this special issue of “Insect growth and development and immunity” reflect well the current status and features of research on insect development and immune in China. The growth and development part covers all developmental stages from egg to adult, mainly focusing on the signal transduction, and the immunity part focuses on biological interactions. In the context of big data, more efforts will be made to combine traditional and modern techniques, and strengthen cooperation, thus making the research branch play a greater role in pest control, insect resource utilization, and food security.
RESEARCH PAPERS
Identification of G protein-coupled receptors in the fat body of the female adults of Locusta migratoria (Orthoptera: Acrididae) and their functions in egg development
YUN Jia-Qi, YANG Jie-Bing, XU Hui-Jing, ZHENG Hong-Yuan, ZHOU Shu-Tang
2022, 65(12):  1571-1581.  doi:10.16380/j.kcxb.2022.12.002
Abstract ( 45 )   PDF (6200KB) ( 27 )   PDF(mobile) (6200KB) ( 5 )     
【Aim】 This study aims to identify the G protein-coupled receptor (GPCR) genes expressed in the fat body of the female adults of Locusta migratoria, and uncover their functions in egg development and ovarian growth of L. migratoria. 【Methods】 Based on the previously obtained transcriptome data of the fat body of the female adults of L. migratoria during the first gonadotropic cycle, identification and cluster analysis of GPCR genes were performed. qRT-PCR was employed to measure the tissue-specific expression patterns of GPCR genes in the brain, thoracic and abdominal ganglia, fat body, ovary and midgut of vitellogenic female adults of L. migratoria. RNAi experiments were carried out to analyze the functions of GPCR genes in egg development and ovarian growth. 【Results】 A total of 29 GPCR genes were newly identified from the fat body transcriptome of female adults of L. migratoria. qRT-PCR results demonstrated that PTH/PTHrPR1 and MSR were significantly highly expressed in the fat body and thoracic and abdominal ganglia of female adults of L. migratoria, respectively, while Mthl4, Mthl6 and GPR119Lwere significantly highly expressed in the midgut, and the expression levels of Octβ1R, CrzR, CCAPR, LGR2, mGluR and GABABR in the brain were significantly higher than those in the other tissues. RNAi screening revealed that knockdown of five GPCR genes, CCAPR, PTH/PTHrPR1, ADGRL3, Mthl15 and DHR, significantly inhibited the primary oocyte development and ovarian growth of L. migratoria. 【Conclusion】 Findings in the present study are helpful for unveiling the regulatory networks of powerful fecundity of insects and exploring novel targets for insect pest control.
Verification of the G4 structure of the embryonic development factor (EDF) gene BmEDF from Bombyx mori embryos and screening of its binding protein
HUANG Qiong, PENG Yu-Ling, FENG Qi-Li, NIU Kang-Kang
2022, 65(12):  1582-1591.  doi:10.16380/j.kcxb.2022.12.003
Abstract ( 29 )   PDF (4780KB) ( 9 )   PDF(mobile) (4780KB) ( 0 )     
【Aim】 This study aims to further explore the possible role and mechanism of G-quadruplex (G4) structure in the regulation of the embryonic development of Bombyx mori by searching for the binding protein of the G4 structure of the embryonic development factor (EDF) gene BmEDF of B. mori. 【Methods】 Circular dichroism (CD) and electrophoretic mobility shift assay (EMSA) were performed to verify whether G4 sequence formed G4 structure in vitro. The effect of the G4 structure of the BmEDF promoter on the regulation of BmEDF expression was verified by the promoter activity experiment. qRT-PCR was performed to determine the expression levels of BmEDF in B. mori embryo at different developmental stages. The protein that could bind to the G4 structure of BmEDF was analyzed by EMSA combined with mass spectrometry. Then, the two candidate proteins BmeIF4H and BmADDH binding with G4 structure were cloned, expressed and purified, respectively. The binding of the candidate proteins BmeIF4H and BmADDH to the G4 structure of BmEDF was verified by EMSA. 【Results】 CD and EMSA experiments demonstrated that the G4 sequence of BmEDF could form G4 structure in vitro. Promoter activity experiments showed that the presence of the G4 structure of BmEDF had a positive regulatory effect on the transcriptional expression of BmEDF. The qRT-PCR results showed that the expression level of BmEDF was significantly increased at 120 h after oviposition. The recombinant BmeIF4H and BmADDH were obtained by prokaryotic expression and purification. EMSA experiments showed that the recombinant BmeIF4H bound to the G4 structure of BmEDF in vitro, while BmADDH did not bind to the G4 structure of BmEDF. 【Conclusion】 The BmeIF4H protein in B. mori embryo may bind to the G4 structure of BmEDF. This study provides the experimental evidence for analyzing the regulatory mechanism of DNA advanced structure in the embryonic development of B. mori.
Cloning and analysis of Pangolin X3, a key gene transcript variant downstream of the Wnt signaling pathway in the silkworm, Bombyx mori
WANG Ye-Jing, FU Qiu-Jie, YIN Zi-Qing, HE Hua-Wei
2022, 65(12):  1592-1597.  doi:10.16380/j.kcxb.2022.12.004
Abstract ( 21 )   PDF (8178KB) ( 10 )   PDF(mobile) (8178KB) ( 0 )     
 【Aim】 This study aims to clone the transcript variant X3 of Pangolin isoforms A/H/I/S (Pangolin X3), a key gene downstream of the Wnt signaling pathway in the silkworm, Bombyx mori, and analyze its sequence and expression characteristics. 【Methods】 Pangolin X3 of B. mori was retrieved from the NCBI database, and the primers were designed according to its coding sequence (CDS). Pangolin X3 was cloned from the midgut and hemolymph of B. mori larvae using PCR, and then verified by sequencing. The sequence characteristics of Pangolin X3 were analyzed using SilkDB 3.0, SMART, multiple sequence alignment and phylogenetic tree. The relative expression levels of Pangolin X3 in different tissues (head, hemolymph, integument, gonads, midgut, anterior silk gland, middle silk gland, posterior silk gland, fat body and Malpighian tubules) of the day-3 5th instar larvae of B. mori were analyzed using qRT-PCR. 【Results】 The CDS of Pangolin X3 (GenBank accession no.: XM_038020921) was cloned from the midgut and hemolymph of B. mori larvae. It has an open reading frame of 1 560 bp in length, encoding 519 amino acid residues with the predicted molecular weight of 55.86 kD and the isoelectric point of 7.53. Pangolin X3 contains a conserved β-catenin binding site and an HMG domain, its amino acid sequence is relatively conserved among different insects, especially the HMG domain that binds to DNA, but some amino acid residues in the N-terminal CTNNB1 domain that binds to β-catenin are variable. Tissue expression profile revealed that the relative expression levels of Pangolin X3 in the midgut, hemolymph and gonads of the day-3 5th instar larvae of B. mori were high, while those in the head, integument, anterior silk gland, middle silk gland, posterior silk gland, fat body and Malpighian tubules were low. 【Conclusion】 In this study, we cloned Pangolin X3 of B. mori and analyzed its sequence and expression characteristics, providing a basis for an in-depth study of the biological function of Pangolin in B. mori.
Functional analysis of pax3 gene in Bombyx mori by the binary transgenic CRISPR/Cas9 system
PU Shang-Kun, WANG Lei, TAN An-Jiang, WEI Guo-Qing
2022, 65(12):  1598-1605.  doi:10.16380/j.kcxb.2022.12.005
Abstract ( 29 )   PDF (8677KB) ( 8 )   PDF(mobile) (8677KB) ( 0 )     
 【Aim】 This study aims to investigate the biological functions of pax3 gene in Lepidoptera insects using the silkworm, Bombyx mori, as a model. 【Methods】 The exon sequence of Bmpax3 from B. mori was verified by PCR amplification. The expression profile of Bmpax3 in the head, cuticle, fat body, midgut, Malpighian tubules, anterior silk gland, middle silk gland, posterior silk gland and gonads (including testis and ovary) of the day-3 5th instar larvae of B. mori was detected by qRT-PCR. The Bmpax3 knockout mutants were constructed using the binary transgenic CRISPR/cas9 system to analyze the effects of Bmpax3 mutation on the larval survival, somite differentiation and gender difference of B. mori. 【Results】 Bmpax3 was expressed in the head, midgut and silk gland of the day-3 5th instar larvae of B. mori, with its highest expression level in the anterior silk gland. The egg hatching rate of the Bmpax3 mutants was about 90%, but about 80% of mutants died in the 1st instar larval stage, and only about 10% of the mutated individuals survived to the adult stage. And there was gender difference in the number of surviving adults, in which the number of male survivors was significantly higher than that of female survivors. About half of the surviving adults showed abnormal differentiation in distal abdominal somites, disorder of cuticle stripes, deficiency of partial abdominal sternum and developmental defects in reproductive organs and other auxiliary organs around them. 【Conclusion】 Bmpax3 mutation has a great impact on the survival and morphological development of B. mori, suggesting that Bmpax3 may participate in the growth and development processes in B. mori.
Identification and expression profiling of CYP450 genes involved in the ecdysone synthesis pathway in Spodoptera litura (Lepidoptera: Noctuidae)
GU Jun, YE Yan, LI Shi-Yu, YUAN Ya-Fei, HUANG Li-Hua
2022, 65(12):  1606-1614.  doi:10.16380/j.kcxb.2022.12.006
Abstract ( 26 )   PDF (2623KB) ( 9 )   PDF(mobile) (2623KB) ( 2 )     
【Aim】 This study aims to explore the expression profiles of CYP450 genes involved in the ecdysone synthesis pathway, so as to provide potential targets for the control of pest insects. 【Methods】The CYP450 genes were identified from the genome of Spodoptera litura by homologous blast using the Bombyx mori CYP450 genes as queries, and their phylogenetic tree was constructed. qPCR was carried out to examine the expression levels of the identified CYP450 genes in different developmental stages (6th instar larva, prepupa and pupa), various tissues (midgut, cuticle and fat body) of these three developmental stages, and the midgut of the 5th instar larvae after the 4th instar larvae fed with the leaves of different host plants [pepper (Capsicum annuum), cucumber (Cucumis sativus), sweet potato (Ipomoea batatas) and peanut (Arachis hypogaea)]. The developmental duration from the 4th instar larva to pupa was recorded after the 4th instar larvae were fed with the leaves of different host plants. In addition, microRNAs (miRNAs) targeting the identified CYP450 genes were predicted using four programs, PITA, miRanda, microTar and RNAhybrid. 【Results】 Six CYP450 orthologs, CYP307A1, CYP306A1, CYP302A1, CYP315A1, CYP314A1 and CYP18A1, involved in the ecdysone synthesis pathway were identified in S. litura, and the phylogenetic tree showed that the six genes belong to two clans, CYP2 and mitochondrial CYP, respectively. CYP306A1, CYP314A1 and CYP18A1 showed the highest expression levels in the 6th instar larvae, prepupae and pupae, respectively, and the highest expression levels in the midgut of the 6th instar larvae, the fat body of prepupae and the cuticle of pupae, respectively. After the 4th instar larvae of S. litura were fed with the leaves of sweet potato and peanut, the developmental duration from the 4th instar larva to pupa was significantly prolonged, and the expression level of CYP306A1 in the midgut of the 5th instar larvae was significantly upregulated, as compared to those fed with the artificial diet. Multiple miRNA binding sites were identified on CYP307A1, CYP315A1, CYP314A1 and CYP18A1. 【Conclusion】 CYP306A1, CYP314A1 and CYP18A1 in the ecdysone synthesis pathway play key regulatory roles in the larva, prepupa and pupa of S. litura, respectively, and are also involved in detoxification of the secondary metabolites in host plants and subject to the control of various miRNAs. These findings not only help to understand the complex mechanism of insect metamorphosis, but also provide potential targets for pest insect control, which will benefit for the sustainable management of pest insects including S. litura.
Screening of the interacting proteins of RNA-binding protein RBP9 in the head of Drosophila melanogaster
SHI Jia-Yuan, MA Da, GU Jia-Hui, QIN Sheng, WANG Sheng-Peng, ZHANG Guo-Zheng, LI Mu-Wang, SUN Xia,
2022, 65(12):  1615-1622.  doi:10.16380/j.kcxb.2022.12.007
Abstract ( 18 )   PDF (2891KB) ( 7 )   PDF(mobile) (2891KB) ( 0 )     
【Aim】 To screen the interacting proteins of RNA-binding protein RBP9 in the head of Drosophila melanogaster. 【Methods】 By using the CRISPR/Cas9 genome editing technology, the coding sequences of 3×Flag and V5 tag were inserted after the start codon ATG of RBP9 and FNE in the head of D. melanogaster adults, respectively, and 3×Flag-RBP9/3×Flag-RBP9 (3FRBP9) and V5-FNE/V5-FNE (VFNE) transgenic D. melanogaster strains were constructed. The interacting proteins of RBP9 in the head of adults of 3FRBP9 and the wild-type strain of D. melanogaster were identified by using immunoprecipitation and mass spectrometry and subjected to bioinformatics analysis. The interaction between RBP9 and FNE proteins was analyzed by immune coprecipitation method. 【Results】 A total of 190 proteins interacting with RBP9, including ELAV and FNE, were identified in the head of D. melanogaster adults by mass spectrometry. KEGG enrichment analysis showed that the genes of these proteins are mainly involved in ribosome, carbon metabolism, tricarboxylic acid cycle, biosynthesis of amino acids and other pathways. The results of immune coprecipitation test validated the interaction between RBP9 and FNE proteins. 【Conclusion】 RNA-binding proteins of the ELAV family interact with each other in the head of D. melanogaster adults. This study provides an important experimental basis for the further functional study of RBP9 in the nervous system development of Drosophila.
Effects of infection of the entomopathogenic nematode Steinernema carpocapsae All on the innate immune response in Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae
LI Er-Tao, LU Qi-Han, ZHANG Dan-Feng, KONG Wei-Jie, AN Chun-Ju
2022, 65(12):  1623-1635.  doi:10.16380/j.kcxb.2022.12.008
Abstract ( 28 )   PDF (20580KB) ( 17 )   PDF(mobile) (20580KB) ( 8 )     
 【Aim】 To investigate the effects of Steinernema carpocapsae All infection on the innate immune response in larvae of the fall armyworm, Spodoptera frugiperda. 【Methods】 The hemocyte types of S. frugiperda larvae were observed and identified under an inverted microscope, and the total numbers of hemocytes in S. frugiperda larvae at different time after infection by S. carpocapsae All were counted. The encapsulation of invading S. carpocapsae All nematodes by S. frugiperda hemocytes was observed under an inverted microscope. The phagocytoic activity of fluorescent Staphylococcus aureus by hemocytes of S. frugiperda larvae was observed under an inverted fluorescence microscope. The phenoloxidase (PO) activity in the hemolymph, the relative expression levels of antibacterial peptide genes, and the antibacterial activity of plasma in S. frugiperda larvae infected with S. carpocapsae All were detected. 【Results】 Five types of hemocytes, prohemocyte, granulocyte, oenocytoide, spherulocyte and plasmatocyte, were found in S. frugiperda larvae. The total numbers of hemocytes in S. frugiperda larvae increased significantly at 9 and 12 h after injection of 1 μL S. carpocapsae All infective juveniles (IJs) at the dose of 3 IJs/μL. The hemocytes from S. frugiperda larvae failed to encapsulate the live and coldkilled S. carpocapsae All nematodes but could encapsulate heat-killed nematodes. The phagocytic activity of fluorescent S. aureus by S. frugiperda hemocytes was significantly inhibited after incubation with live S. carpocapsae All nematodes, but not with cold- and heat-killed S. carpocapsae All nematodes. The PO activity in the hemolymph of S. frugiperda larvae decreased first, then increased, and finally decreased after injection of 1 μL S. carpocapsae All at the dose of 3 IJs/μL. The relative expression levels of antimicrobial peptide genes Attacin-A2, Attacin-B1, Cecropin-B3, Cecropin-D, Gallerimycin, Gloverin-3 and Lebocin-2 in S. frugiperda larvae were significantly induced at 12 h after S. carpocapsae All infection, and then recovered to the control level or lower than the control level at 24 h after infection. The antibacterial activity of S. frugiperda plasma increased significantly at 12 h after S. carpocapsae All infection, but was not significantly different between the treatment group and the control group at 24 h after infection. 【Conclusion】 In the early stage of infection, S. carpocapsae All would inhibit the innate immune response in S. frugiperda larvae, then the immune system in S. frugiperda would be initiated for trying to defend against S. carpocapsae All, and in the late stage the immune system in S. frugiperda would be inhibited or destroyed with the successful colonization of nematodes. The results obtained in this study provide a basis for further understanding the immune mechanisms involved in the interaction between nematodes and S. frugiperda, and lay a theoretical foundation for further improving the control efficacy of entomopathogenic nematodes against S. frugiperda larvae.
Effects of key factors Dicer-1 and Argonaute-1 in microRNA pathway on the immunity defense in the pea aphid, Acyrthosiphon pisum(Hemiptera: Aphididae)
XU Zhen-Zhen, JIANG Xin-Yi, SHI Su-Ke, LÜ Zhi-Qiang
2022, 65(12):  1636-1644.  doi:10.16380/j.kcxb.2022.12.009
Abstract ( 18 )   PDF (1838KB) ( 9 )   PDF(mobile) (1838KB) ( 0 )     
【Aim】 To study the function of two key components Dicer-1 and Argonaute-1 (Ago-1) of microRNA (miRNA) pathway in Acyrthosiphon pisum in defense against bacteria and fungi and to strengthen the knowledge of A. pisum immune system. 【Methods】 qRT-PCR was used to detect the expression levels of Dicer-1 and Ago-1 in A. pisum adults infected with the bacteria Staphylococcus aureus andEscherichiacoli, andthefungusBeauveriabassiana, respectively. After Dicer-1 and Ago-1 of A. pisum adults were silenced by RNAi through injection method followed by infection of S. aureus, E. coli and B. bassiana, the proliferation of the bacteria and the fungus and the survival rate of A. pisum adults were examined. 【Results】 The expression levels of Dicer-1 and Ago-1 in A. pisum adults injected by S. aureus, E. coli and B. bassiana were up-regulated as compared to those in the control group (treated with 0.85% NaCl solution). After RNAi of Dicer-1, the colony-forming unit (CFU) in A. pisum adults at 36 h post infection with S. aureus significantly increased as compared to that in the control group (injected with dsLTA), but there was no significant difference in the survival rate at 7 d after infection between the Dicer-1-silenced group and the control group. After RNAi of Dicer-1, the CFUs in A. pisum adults at 12 and 24 h post infection of E. coli significantly increased, but the survival rate at 7 d post infection significantly decreased, as compared with those in the control group. At 6 d after infection of B. bassiana, the fungal spores in the Dicer-1silenced group significantly increased, but their survival rate at 7 d post infection significantly decreased, as compared with those in the control group. When Ago-1 was knocked down by RNAi, the CFUs in A. pisum adults at 36 h after infection by S. aureus and 24 h after infection by E. coli were significantly higher than those in the control group, respectively, and the survival rate of A. pisum adults infected by S. aureus at 7 d post infection decreased significantly as compared with that in the control group, while the survival rate of adults at 7 d post infection by E. coli had no significant change. At 6 d after infection with B. bassiana, the Ago-1-silenced A. pisum adults bore a significantly larger amount of fungal spores than the control group, but had significantly decreased survival rate at 7 d post infection as compared with the control group. 【Conclusion】 Two crucial elements Dicer-1 and Ago-1 in mRNA pathway are involved in the immune defense of A. pisum against bacteria and fungi, particularly against bacteria.
Gut bacteria reduce the Bt susceptibility in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), by competing for niche and protecting the inner wall of gut
TAO Xin-Ping, JIA Yuan-Hong, SUN Yan, HAN Shun-Cai, XIA Xiao-Feng
2022, 65(12):  1645-1657.  doi:10.16380/j.kcxb.2022.12.010
Abstract ( 23 )   PDF (11385KB) ( 14 )   PDF(mobile) (11385KB) ( 1 )     
【Aim】 Gut microbiota might play an important role in mediating host resistance to Bacillus thuringiensis (Bt). The purpose of this study is to explore the effect of gut bacteria on the insecticidal activity of Bt in the diamondback moth, Plutella xylostella, and analyze the action mechanism of gut bacteria in host protection. 【Methods】 The survival rates of the 3rd instar larvae of P. xylostella feeding on the sterile artificial diet and on the artificial diet containing total gut bacteria, Enterobacter sp. IAE5 (EbPXG5), Bt strain Bt8010, Bt8010+total gut bacteria and Bt8010+EbPXG5, respectively, as well as the survival rates of P. xylostella after feeding on the sterile artificial diet and artificial diet containing EbPXG5 supernatant, EbPXG5 cell lysate solution, Bt8010+EbPXG5 supernatant, Bt8010+EbPXG5 cell lysate solution and Bt8010, respectively, were measured, and then the influence of gut bacteria on the Bt susceptibility of P. xylostella at different time was analyzed were analyzed. The plate culture technique was used to assay the abundance of EbPXG5 and Bt8010 in the gut and haemolymph of the 3rd instar larvae of P. xylostella fed with the artificial diets containing EbPXG5, Bt8010 and Bt8010+EbPXG5, respectively, and the inhibitory effect of EbPXG5 on Bt8010 in vitro, and the effect of gut bacteria on the proliferation of Bt8010 in the gut of P. xylostella and their invasion into the blood cavity was analyzed. The inner wall morphology of the gut tissues of the sterile 3rd instar larvae of P. xylostella and the gut tissues of P. xylostella fed with EbPXG5, Bt8010 and EbPXG5+Bt8010, respectively, were observed by scanning electron microscope to reveal the protective function of gut bacteria on the inner wall of gut. 【Results】 The survival rates of the 3rd instar larvae of P. xylostella feeding on the diet containing total gut bacteria and the diet containing EbPXG5 had no significant difference compared with that in the control feeding on the sterile artificial diet, but the survival rates of the 3rd instar larvae feeding on the diet containing Bt8010+EbPXG5 and the diet containing Bt8010+total gut bacteria were significantly higher than those feeding on the diet containing Bt8010 at 24, 36, 48 and 60 h. The survival rates of the 3rd instar larvae feeding on the diets containing EbPXG5 supernatant and EbPXG5 cell lysate solution had no difference from that of the control group, and the survival rates of the 3rd instar larvae feeding on the diets containing Bt8010+EbPXG5 supernatant and Bt8010+EbPXG5 cell lysate solution also had no difference from that of the larvae feeding on the diet containing Bt8010 alone. There was no significant difference in the abundance of EbPXG5 in the gut of the 3rd instar larvae of P. xylostella feeding on the artificial diets containing EbPXG5 alone and Bt8010+EbPXG5, respectively, but the abundance of Bt8010 in the gut of the 3rd instar larvae feeding on the diet containing Bt8010+EbPXG5 was significantly lower than that feeding on the diet containing Bt8010 alone at 24, 36 and 48 h. The abundance of EbPXG5 in the haemolymph of P. xylostella fed with the diet containing Bt8010+EbPXG5 was higher than that fed with the diet containing EbPXG5 alone at 36 and 48 h; however, the abundance of Bt8010 in the haemolymph of P. xylostella fed with the diet containing Bt8010+EbPXG5 was significantly lower than that fed with the diet contaning Bt8010 alone at 36 and 48 h. The Oxford cup bacteriostatic test showed that EbPXG5 had no inhibitory effect on Bt8010 in vitro. The results of scanning electron microscope observation showed that Bt8010 could destroy the larval gut cavity to form holes, mediate Bt8010 and other bacteria to cross the gut barrier and enter the hemolymph of P. xylostella. EbPXG5 could colonize the inner wall of the gut cavity of P. xylostella, weaken the damage of Bt8010 to the inner wall of the gut, and reduce the abundance of Bt8010 in the gut and hemolymph. 【Conclusion】 Gut bacteria EbPXG5 plays an important role in protecting P. xylostella and reducing the susceptibility of P. xylostella to Bt. It may weaken the colonization and invasion of pathogens by competing for niche and protecting the inner wall of gut, thus reducing the susceptibility of host to Bt. The results have important reference value for promoting the biological control and integrated management of P. xylostella.
Mechanism of action of nuclear receptor factor FTZ-F1 in response to the stress of chlorfenapyr and phoxim in Spodoptera litura (Lepidoptera: Noctuidae)
SONG Yan, LIU Zhi-Xiang, TAN An-Jiang, SHENG Sheng
2022, 65(12):  1658-1667.  doi:10.16380/j.kcxb.2022.12.011
Abstract ( 23 )   PDF (4953KB) ( 17 )   PDF(mobile) (4953KB) ( 0 )     
 【Aim】 This study aims to reveal the mechanism of action of FTZ-F1, a key nuclear receptor factor in insect ecdysone signaling pathway, in response to the stress of chlorfenapyr and phoxim in Spodoptera litura. 【Methods】 The FTZ-F1 gene of S. litura was identified by bioinformatics methods, sequence alignment was conducted and phylogenetic tree was constructed. The mulberry leaves treated with LC30 of chlorfenapyr and phoxim by leaf dipping method were fed to the 3rd instar larvae of S. litura, and the survived larvae were collected at 1, 12, 24, 36 and 48 h, respectively, after feeding on the leaves, and the expression levels of SlFTZ-F1 in the larvae were detected by qRT-PCR. SlFTZ-F1 gene was silenced by RNAi technology, and the expression level of SlFTZ-F1 was detected by qRT-PCR after dsRNA injection. The mulberry leaves treated with LC30 of chlorfenapyr and phoxim by leaf dipping method were fed to the 3rd instar SlFTZ-F1-silenced larvae, and the mortality rates of S. litura larvae were recorded at 24 and 48 h after feeding. Eight glutathione S-transferase (SlGST) genes of S. litura were selected and qRT-PCR was used to detect the expression levels of these SlGST genes in the SlFTZ-F1-silenced S. litura larvae. 【Results】 The open reading frame of SLFTZ-F1 of S. litura is 1 665 bp in length, encoding 555 amino acids with the isoelectric point of 6.39 and the theoretical molecular weight of 61.77 kD. SlFTZ-F1 contains DNA-binding domain, FTZ-F1 box and ligand-binding domain. The phylogenetic tree showed that SlFTZ-F1 and SfFTZ-F1 in Spodoptera frugiperda were clustered into a subbranch. The expression levels of SlFTZ-F1 in the 3rd instar larvae of S. litura at 1, 24 and 36 h after feeding on the mulberry leaves treated with LC30 of chlorfenapyr, and at 24 and 36 h after feeding on the mulberry leaves treated with LC30 of phoxim were significantly up-regulated as compared to those in the control feeding on the mulberry leaves treated with ddH2O. The expression level of SlFTZ-F1 in the 3rd instar larvae of S. litura at 48 h after dsSlFTZ-F1 injection was significantly decreased as compared with that in the control group injected with dsGFP. When the 3rd instar SlFTZ-F1-silenced larvae of S. litura had been fed on the mulberry leaves treated with LC30 of chlorfenapyr and phoxim, respectively, for 48 h, their mortality rates were significantly increased by 22% and 28%, respectively. The expression levels of the eight SlGST genes in the SlFTZ-F1-silenced larvae of S. litura were significantly down-regulated as compared to those in the control. 【Conclusion】 The expression of SlFTZ-F1 gene of S. litura larvae is significantly induced by chlorfenapyr and phoxim. After silencing SlFTZ-F1, the sensitivity of S. litura larvae to chlorfenapyr and phoxim significantly increases, and the expression of detoxification enzyme SlGST genes is significantly inhibited, suggesting that the development-related transcription factor FTZ-F1 plays an essential role in response to the stress of commonly used insecticides in S. litura.
Effects of momordicin I on the expression of chitinase gene (SlCht) and chitinase synthase gene (SlCHS-A) in Spodoptera litura (Lepidoptera: Noctuidae) and its growth and development
ZHANG Zhan-Tao, LIN Xiao-Ju, GU Xiao-Ting, YE Kai-Xiang, ZHANG Wei-Zhao, JIN Feng-Liang, XU Xiao-Xia
2022, 65(12):  1668-1677.  doi:10.16380/j.kcxb.2022.12.012
Abstract ( 13 )   PDF (13852KB) ( 7 )   PDF(mobile) (13852KB) ( 0 )     
【Aim】 Chitinase and chitin synthetase are of great importance to the metamorphosis in insects. This study aims to elucidate the effects of momordicin I on the expression of chitinase and chitin synthase genes in Spodoptera litura and its growth and development. 【Methods】 The expression levels of chitinase gene (SlCht) and chitinase synthase gene (SlCHS-A) in different developmental stages (egg, larva, prepupa, pupa and adult) and tissues (integument, midgut, fat body, hemocyte, head and Malpighian tubules) of the 4th-6th instar larvae of S. litura, and in various tissues of the 6th instar larvae at 24, 48 and 72 h after injection with momordicin I solution (4 μg/individual) were detected by RT-qPCR. The effects of injection of momordicin I at different concentrations (31.25, 62.5, 125, 250 and 500 ng/individual) into the 4th instar larvae of S. litura on the larval and pupal duration, larval weight gain, pupal weight, pupal length, pupation rate, emergence rate and survival rate were analyzed, and the phenotypic changes of S. litura larvae were also observed under stereoscopic microscope. 【Results】 SlCht and SlCHS-A showed developmental stagespecific expression in S. litura, both with the highest expression levels in the egg stage but significantly lower expression levels in the larval and prepupal stages, and with the highest expression level in the 6th larval instar during the larval stage. SlCht and SlCHS-A also exhibited tissue-specific expression in the 6th instar larvae of S. litura, both being highly expressed in hemocyte and integument, and lowly expressed in head, midgut and fat body. Injection of momordicin I into the 6th instar larvae of S. litura induced the decreased expression of SlCht and SlCHS-A genes in their various tissues. After injection of momordicin I into the 4th instar larvae of S. litura, the growth and development of S. litura were inhibited, the larval weight gain was delayed, the developmental duration was prolonged, the pupation rate was decreased and even failure to pupate was observed, and high malformation rates of larvae and pupae were found. 【Conclusion】 Momordicin I can inhibit the growth and development of S. litura by inducing the decreased expression of SlCht and SlCHS-A. This study provides a new theoretical basis for further elucidation of the inhibitory mechanism of momordicin on the growth and development of S. litura, and lays a foundation for the application of momordicin I in the prevention and control of this insect pest.
Effects of multiple mating on the spermatophore formation and fecundity of Plutella xylostella (Lepidoptera: Plutellidae)
ZOU Ming-Min, LIU Li-Li, DONG Shi-Jie, HUANG Meng-Qi, CAO Min-Hui, YOU Min-Sheng, PENG Lu,
2022, 65(12):  1678-1686.  doi:10.16380/j.kcxb.2022.12.013
Abstract ( 24 )   PDF (18734KB) ( 27 )   PDF(mobile) (18734KB) ( 21 )     
【Aim】 The diamondback moth, Plutella xylostella, is a cosmopolitan lepidopteran pest that mainly attacks cruciferous plants. Its strong reproductive capacity is one of the main reasons why it becomes the pest most difficult to control in the field. Mating is a physiological process necessary for the bisexual reproduction of most insect species. Clarifying the mating behavior and physiological response of female and male adults is of great significance for population monitoring and control of P. xylostella. 【Methods】 The gonad and spermatophore formation of P. xylostella adults were observed anatomically. The mating and remating capacity, spermatophore formation and digestion of P. xylostella adults, and the effects of mating frequency on the spermatophore formation and female fecundity were measured and analyzed by behavioral and biological experiments. 【Results】 During the mating process, the seminal fluid of male adults of P. xylostella was transferred to female adults in the form of spermatophore, which is a white, opaque, balloonlike structure within the bursa copulatrix. The spermatophore could be sufficiently digested and absorbed after mating. The observation results of mating capacity showed that both female and male adults of P. xylostella had multiple mating behaviors. After the first mating, for the male adults there was a short delay in re-mating, and the mating success rate was 54.6% within 20 min, which was significantly lower than that of the first mating. Although the multiple mating did not affect the mating duration of male adults, the mating history significantly inhibited the spermatophore size and female fecundity. There was an obvious re-mating inhibition in mated female adults, of which the mating rate was significantly lower than that of the unmated females within 12 h, suggesting that re-mating inhibition depends on the rates of spermatophore digestion and absorption after the first mating. There was no significant difference in the oviposition amount and egg hatching rate between female adults with multiple and single mating. 【Conclusion】 Multiple mating results in delayed and inhibited re-mating of female and male adults of P. xylostella, respectively. The spermatophore produced by male adults with multiple mating is significantly reduced, and the oviposition amount and egg hatching rate of female adults get no benefit from multiple mating. This study provides a theoretical foundation for better understanding the reproductive regulation mechanism of P. xylostella.
REVIEW ARTICLES
Research progress of insect hemocytin
WANG Jing-Jing, HU Hong-Wang, HU Qiong-Bo
2022, 65(12):  1687-1694.  doi:10.16380/j.kcxb.2022.12.014
Abstract ( 26 )   PDF (5662KB) ( 10 )   PDF(mobile) (5662KB) ( 0 )     
Our research group previously found that destruxin A interacts with the hemocytin of the silkworm, Bombyx mori, and strongly suppresses hemolymph immunity, suggesting that hemocytin may become a novel target for pesticide. Therefore, it is necessary to further understand hemocytin. Hemocytin, as a lectin, is an important factor in insect hemolymph immunity to mediate the process of coagulation, nodulation and encapsulation and prevent hemolymph spillage and microbial invasion caused by epidermal breakage, as well as be involved in the fixation and removal of invaded pathogens. Insect hemocytin generally consists of 3 000-4 000 amino acids with multiple and repeatedly arranged domains including FA58C (coagulation factor 5 or 8 C-terminal), VWD (von Willebrand factor type D), TIL (trypsin inhibitor like cysteine rich), VWC (von Willebrand factor type C), CT (C-terminal cystine knotlike), C8 (8 conserved cysteine residues), ChtBD2 (chitin-binding domain type 2), and MUC (mucin-2 protein WxxW repeating region). The amino acid sequence similarity of hemocytin between different insects is quite low, but the domain sequence is highly conserved. Hemocytin is biosynthesized by hemocytes and secreted into the hemolymph in mature form. Hemocytin is the main component of blood clot, forming soft clot by coagulating hemocytes and clotting factors through its fibrous structure to seal the wound, and then forming hard clot and scab through crosslinking. Hemocytin plays an important role in the process of nodulation and encapsulation, agglutinating hemocytes, immune factors and pathogens, and finally combining with melanization to isolate and kill pathogens. Overall, insect hemocytin has not been studied in depth. Analysis of the molecular mechanism of hemocytin regulation of insect immunity is important to enrich the basic research of insect immunology and promote the development of new insecticides based on hemocytin as the target.
Function and mechanism of action of Drosophila insulin-like peptide 8 (Dilp8)
NAN Nan, YAN Zhi-Peng, ZHANG Ya-Ru, QIN Guo-Hua, SANG Nan
2022, 65(12):  1695-1700.  doi:10.16380/j.kcxb.2022.12.015
Abstract ( 19 )   PDF (1147KB) ( 7 )   PDF(mobile) (1147KB) ( 0 )     
As a model organism, Drosophila has the advantages of short growth cycle, high reproductive capacity, and low research cost. Moreover, 65% of genes in Drosophila are homologous with those in human, especially the simple genetic background of Drosophila makes Drosophila play an important role in the study of biological growth and development, pathological mechanism and gene expression regulation. So far, eight insulins, Drosophila insulin-like peptides 1-8 (Dilp1-8), have been identified in Drosophila, and studies of the Drosophila insulin signaling pathway have focused on its regulation of growth and development and energy metabolism, which is mainly mediated through Dilp1-7. Little is known about the function of Dilp8 and the molecular mechanism of its action. In this article, we summarized the results of studies on Dilp8 since its discovery. Dilp8 was mainly expressed in imaginal discs and ovaries of adult female Drosophila. Dilp8 allows Drosophila to grow into individuals with a normal-sized and symmetrical body by regulating tissue growth and developmental timing. Dilp8 in damaged larvae mitigates abnormal growth by delaying developmental time. After being activated, Dilp8 enters the central nervous system and specifically binds to its receptor leucine-rich repeat-containing G protein-coupled receptor 3 (Lgr3), thereby inhibiting the synthesis of ecdysone to control the growth and development of Drosophila. It has been suggested that Lgr3 is associated with sex regulation in Drosophila. Dilp8 regulates the ovulatory capacity of adult female Drosophila. In addition, tumour-derived Dilp8 is associated with anorexia of Drosophila. Dilp8/Lgr3 is highly homologous with human INSL3/RXFP2. The molecular mechanism of action of Dilp8 needs further exploration.
Research advances in anticoagulant factors from ticks
NI Jun, SHEN Shu, DENG Fei
2022, 65(12):  1701-1716.  doi:10.16380/j.kcxb.2022.12.016
Abstract ( 18 )   PDF (2187KB) ( 9 )   PDF(mobile) (2187KB) ( 1 )     
Ticks are zoonotic ectoparasites transmitting pathogens to hosts via biting and feeding on hosts, which are associated with various diseases. Coagulation reaction is an important physiological process and plays critical roles in physiological hemostasis in humans and animals. During the long time of biting and feeding processes on hosts, ticks can secrete a variety of anticoagulants to inhibit coagulation reactions, which would guarantee the ticks to have blood meals for a long time. To date, the major tickderived anticoagulants which have been identified and recognized according to their functions include protease inhibitors, fibrin(ogen)olytic agents, platelet aggregation inhibitors, and vasoactive proteins. These anticoagulants can act on the intrinsic pathway, extrinsic pathway, and key steps in the common pathway of the coagulation cascade, promote fibrinolysis, and inhibit platelet activation, thereby inhibiting the coagulation response in the host blood vessels. Protease inhibitors mainly inhibit the activities of thrombin and factor Xa in the common pathway of coagulation cascade. Fibrin(ogen)olytic agents cause the hydrolysis of fibrinogen and delay the formation of fibrin clots. Platelet aggregation inhibitors can suppress platelet aggregation by degrading platelet aggregation agonists and binding thromboxane A2 (TXA2) and αIIBβ3 integrin on platelet surface. Vasoactive proteins inhibit host vasoconstriction, and wound healing and angiogenesis. In addition, there are some other protein molecules secreted by ticks that pose anticoagulation effects through different pathways. In this article, we summarized the anticoagulant proteins and small molecules found in ticks so far and their anticoagulant mechanisms, which will promote understanding of the mechanism and physiological significance of anticoagulation process in hosts triggered by ticks, and will provide important reference for developing new tickderived anticoagulant drugs and new antithrombotic therapies.
CONTENTS
Contents of Vol. 65 Issue 12
2022, 65(12):  1717-1717. 
Abstract ( 9 )   PDF (688KB) ( 6 )   PDF(mobile) (688KB) ( 0 )     
GENERAL CONTENTS

General Contents of Volume 65(1-12)

2022, 65(12):  1718-1718. 
Abstract ( 11 )   PDF (1882KB) ( 6 )   PDF(mobile) (1882KB) ( 1 )