Acta Entomologica Sinica

Genetic analysis of the non-diapause red egg mutant Re-nd in the silkworm, Bombyx mori

ZHANG Yu-Jing, ZHANG Hai-Yan, SHEN Guan-Wang, WU Jin-Xin, JIA Lin-Bang, MAO Xue-Qin, JIAO Meng-Yao, LIN Ying

2020, 63(11): 1287-1294. doi:10.16380/j.kcxb.2020.11.001

Abstract ( 60 )

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【Aim】 Re-nd, a non-diapause red egg mutant of the silkworm, Bombyx mori, is a new egg color mutant. It was obtained by mutagenesis of the C108 strain induced by the chemical mutagen N-methyl-N-nitrosourea (MNU), belonging to serous membrane mutation. This study aims to analyze the mechanism of mutant phenotype by traditional genetic methods, so as to lay a foundation for further cloning, functional research and application of the mutant genes of Re-nd. 【Methods】 The hybridizing, sib mating and backcrossing between non-diapause mutant Re-nd and the wild-type diapause bivoltine Dazao strain and non-diapause polyvoltine N4 strain of B. mori, respectively, and the genetic analysis were carried out. Meanwhile, the hybridizing, sib mating and backcrossing between Re-nd and diapause egg color mutants with the known mutants such as white egg mutant w-2, peach red eye white egg mutant pe and red egg mutant re of B. mori, respectively, and the genetic analysis were also carried out. 【Results】 The results showed that the non-diapause eggs of F₁ hybrids of Re-nd with Dazao and N4 were both in light red. The non-diapause eggs of F₂ generation of sib mating were in red, light red and light yellow with the ratio of the number of red eggs (including light red eggs) to the number of light yellow eggs basically conforming to 3∶1. The nondiapause eggs of backcross B1 generation were in red and light yellow, with the ratio of the number of red eggs to the number of the light yellow eggs being basically consistent with 1∶1. The diapause eggs of F₁ hybrids of Re-nd with w-2 and pe were in light brown. The diapause eggs of F₂ hybrid of Re-nd with w-2 were in normal dark brown, light brown, yellow and light yellow with slightly red, while the non-diapause eggs of F₂ hybrid were in red, light yellow with slightly red, orange-yellow and light yellow. The F₂ hybrid eggs of Re-nd with pe were all diapause eggs in normal dark brown, light brown, light yellow with slightly red and red. The hybrid diapause eggs of Re-nd with re in F₁were in light brown, and those of in F₂ were all diapause eggs in normal dark brown, light brown and red. The diapause eggs in re parents were in red, and no new egg color separation was found in the hybrid eggs of Re-nd with re in F₂. 【Conclusion】 Through the hybridization and genetic analysis, it was confirmed that Re-nd mutant is an independent dominant inheritance, and the mutant gene of Re-nd should be located in the downstream of the mutant genes of w-2 and pe and may be involved in the process of further metabolism of 3-hydroxy-caninuric acid to ommatins at the later stage of ocular pigment biosynthesis, which is different from the wild-type egg pigment metabolism branch.

Prokaryotic expression, purification and juvenile hormone-binding modes of the juvenile hormone receptors PxMet-1 and PxMet-2 of Plutella xylostella (Lepidoptera: Plutellidae)

PENG Lu, QIN Yu-Dong, ZOU Ming-Min, DONG Shi-Jie, LIU Li-Li, YOU Min-Sheng

2020, 63(11): 1295-1304. doi:10.16380/j.kcxb.2020.11.002

Abstract ( 43 )

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【Aim】 Methoprene-tolerant (Met) proteins belong to the bHLH/PAS family of transcription factors and their complexes with the other members of this family are responsible for transducing the juvenile hormone (JH) signal. This study aims to clone and express the JH receptor Met genes of Plutella xylostella (PxMet-1 and PxMet-2), to purify their proteins and to analyze the JH-binding modes of the PxMet-1 and PxMet-2, so as to provide the basis for further clarifying the function of PxMet proteins. 【Methods】 Based on the NCBI database, the cDNA sequences of PxMet-1 and PxMet-2 of P. xylostella were cloned and verified. PxMet-1 and PxMet-2 sequences were ligated with the prokaryotic expression vector pGEX-KG to construct recombinant plasmids pGEX-KG-PxMet-1 and pGEX-KG-PxMet-2, respectively, which were then introduced into Escherichia coli Rosetta (DE3) for expression. The fusion proteins of PxMet-1 and PxMet-2 were purified with 5 mL HisTrap^TM HP and GSTTrap^TM HP columns, respectively. The JH-binding modes of PxMet-1 and PxMet-2 were analyzed using molecular docking software. 【Results】 The cloned PxMet-1 (GenBank accession no.: MK697672) and PxMet-2 (GenBank accession no.: MT996234) sequences were similar to the previously reported sequences, except for one nonsynonymous mutation located in the 41st amino acid of the PxMet-2 gene, changing from glycine (Gly) to alanine (Ala). The three-dimensional structures of PxMet-1 and PxMet-2 are similar, including a typical helix-loop-helix. Soluble PxMet fusion proteins with His and GST double tags were obtained using in vitro prokaryotic expression. The optimal expression conditions of PxMet-1 were 0.3 mmol/L IPTG induction under 16℃ for 16 h, while those of PxMet-2 were 0.1 mmol/L IPTG induction under 16℃ for 16 h. The highly purified fusion proteins of PxMet-1 and PxMet-2 were obtained after elution with 150 mmol/L imidazole and 20 mmol/L reduced glutathione, respectively. Both SDS-PAGE and Western blot analysis indicated that the specific protein bands of around 89.2 and 106 kD were consistent with the predicted size of PxMet-1 and PxMet-2, respectively. The molecular docking analysis results showed that there is an interaction site with JH in the PAS-B conserved domain of PxMet-1 and PxMet-2, which is consistent with that of Tribolium castaneum Met. 【Conclusion】 Soluble proteins PxMet-1 and PxMet-2 can be effectively expressed in vitro using the pGEX-KG prokaryotic expression system, and PxMet-1 and PxMet-2 proteins are likely to be molecular receptors of JH in P. xylostella. This study provides a solid foundation for further analysis of the PxMet functions and better understanding of the molecular mechanisms that may underlie the JH-mediated development and reproduction of P. xylostella.

Gain-of-function screen identifies the role of miR-2 in mitochondrial homeostasis in Drosophila (In English)

LI Hao-Miao, ZHAO Mei-Qi, ZHANG Feng-Chao, SHEN Jie, ZHANG Jun-Zheng

2020, 63(11): 1305-1313. doi:10.16380/j.kcxb.2020.11.003

Abstract ( 34 )

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【Aim】 The homeostasis of mitochondria is maintained by a wide range of molecular processes in eukaryotic cells. Very recently, microRNAs (miRNAs) are emerging as vital players of mitochondrial homeostasis. However, our understanding of how miRNAs regulate mitochondrial homeostasis is still incomplete. Our study aims to examine the roles and mechanisms of miRNAs in mitochondrial homeostasis regulation. 【Methods】 A gain-of-function screen was performed in Drosophila melanogaster during which miRNAs were over-expressed in the larval fat body cells and the mitochondrial integrity was monitored. The targets of miRNAs were predicted by bioinformatics methods and RNAi knock-down experiments were performed to examine their effects on mitochondrial morphology. 【Results】 A total of 106 miRNAs were screened in larval fat body of D. melanogaster, among which the over-expression of 21 miRNAs resulted in developmental defects of fat body. When over-expressed in the larval fat tissue of D. melanogaster, 10 miRNAs led to lethality at the early larval stage, while the other 11 miRNAs led to pupal lethality. Over-expression of miR-2 was found to result in abnormal aggregation of mitochondria in the larval fat body cells of D. melanogaster. Sequence analysis revealed that the Pink1 gene may be a target of miR-2. The expression level of Pink1 gene was shown to be down-regulated by miR-2 over-expression. Genetic interaction experiments demonstrated that over-expression of Pink1 was sufficient to rescue the abnormal aggregation of mitochondria caused by miR-2. 【Conclusion】 Our data support the view that miR-2 likely targets Pink1 to modulate mitochondrial homeostasis.

Prokaryotic expression, polyclonal antibody preparation and functional characterization of the Niemann-Pick type C1 protein AcNPC1 of Apis cerana cerana (Hymenoptera: Apidae)

LIU Yong-Mei, SHI Hong-Xia, LI Yan, MA Zhen-Gang, WANG Lin-Ling, XU Jin-Shan, ZHOU Ze-Yang, DANG Xiao-Qun

2020, 63(11): 1314-1324. doi:10.16380/j.kcxb.2020.11.004

Abstract ( 31 )

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【Aim】 Human Niemann-Pick disease type C (NPC) is an inherited disease due to mutations in the NPC1 gene. As one of the important receptors in host cells for virus entry mainly responsible for the transport of intracellular cholesterol, NPC1 protein has attracted much attention in recent years. This study aims to explore the relationship between NPC1 protein and Chinese sacbrood virus (CSBV) infection. 【Methods】 The AcNPC1 gene of Apis cerana cerana was amplified by PCR and then cloned into the prokaryotic expression vector pET-30a. The recombinant vector was transformed into Escherichia coli Rosetta^TM (DE3) strain. The recombinant protein was expressed by IPTG induction and purified by Ni-NTA column. The polyclonal antibody was prepared by immunizing mouse with the purified recombinant protein. siRNA targeting AcNPC1 was synthesized and fed to A. c. cerana larvae. The expression levels of AcNPC1 gene and VP1 gene of CSBV in the A. c. cerana larvae infected by CSBV at different time post RNAi were detected by RT-qPCR and analyzed. 【Results】 The recombinant expression vector pET-30a-AcNPC1 was successfully constructed. The soluble AcNPC1 protein of about 36 kD was effectively expressed in E. coli. The recombinant protein with high purity was acquired by affinity purification. The polyclonal antibody was successfully prepared from immunized mouse. Western blot analysis showed that AcNPC1 antibody could hybridize to two bands, which may be partially degraded during membrane protein extraction. The AcNPC1 mRNA levels in CSBV-infected larvae of A. c. cerana at 12, 24 and 48 h post infection were not significantly different from those in the normal larvae, while the AcNPC1 mRNA level in CSBV-infected larvae at 72 h post infection was significantly up-regulated as compared to that in the normal larvae. The RNAi test results revealed that all three interference fragments (siRNA1, siRNA2 and siRNA3) of AcNPC1 downregulated the expression of AcNPC1 in the normal larvae by 73.20%, 72.81%, and 54.78%, and in the CSBV-infected larvae by 43.90%, 59.85%, and 57.67%, respectively, at 24 h post RNAi. The VP1 gene of CSBV was down-regulated by 67.65% at 72 h post RNAi of AcNPC1. 【Conclusion】 Using prokaryotic expression system we effectively expressed AcNPC1 in vitro, and prepared its polyclonal antibody. The AcNPC1 expression in A. c. cerana larvae was interfered using the in vitro synthesized siRNA, suggesting that the expression level of target gene can be successfully downregulated by RNAi via feeding bees. However, the RNAi tests indicate that the decline of AcNPC1 expression may not directly affect the infection of CSBV. This study lays a foundation for further elucidation of the potential functions of AcNPC1.

Effects of Varroa destructor on the respiratory metabolism of Apis mellifera ligustica workers

TAN Jing, WU Jiang-Li, TU Yang-Yang, Tessema AYNALEM, YU Hui-Min, LI Nan-Nan, LI Xiao-Ying, XU Shu-Fa

2020, 63(11): 1325-1332. doi:10.16380/j.kcxb.2020.11.005

Abstract ( 27 )

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【Aim】 The Italian honey bee, Apis mellifera ligustica, is one of the most economically important pollinators in the world, and plays important roles in maintaining the ecological balance, improving the output of agricultural products and ensuring food safety. However, the bee suffers from huge annual loss worldwide due to infestation of Varroa destructor. The purpose of this study is to investigate the effects of V. destructor on the respiratory metabolism of A. mellifera ligustica workers, so as to lay a foundation for further studying the interaction between the mite and the bee. 【Methods】 The oxygen consumption, CO₂ emission and respiration quotient of V. destructor-infected and healthy workers of A. mellifera ligustica at different developmental stages (4-day-old larva, 5-day-old pupa, newly emerged adult and 6-day-old adult) were measured using SSI multi-channel insect respiration instrument, and the characteristics of their changes were analyzed. Meanwhile, the expression levels of respiratory metabolism-related genes (Coq7, COXⅠ, CytB, CytC and IF-2mt) in V. destructor-infected and healthy adult worker bees were analyzed using real-time fluorescence quantitative PCR (RT-qPCR). 【Results】 The oxygen consumption and CO₂ emission of A. mellifera ligustica worker bees first increased and then decreased after infection by V. destructor. After infection by V. destructor, the oxygen consumption decreased from 0.0244 mL/min in the 5-day-old pupal stage of A. mellifera ligustica to 0.0093 mL/min in the 6-day-old adult stage, and the CO₂ emission decreased from 0.0174 mL/min in the 5-day-old pupal stage to 0.0040 mL/min in the 6-day-old adult stage, which was significantly lower than that of the healthy worker bees of the same developmental stage. The respiratory quotient of healthy worker bees of A. mellifera ligustica increased gradually with larval age, and reached the peak (0.9169) at the 6-day-old adult stage, while the respiratory quotient of the V. destructor-infected worker bees decreased, and was the lowest (0.4424) at the 6-day-old adult stage, which was significantly lower than that of the healthy worker bees of the same developmental stage. The RT-qPCR results showed that the relative expression levels of CytB and CytC genes in the V. destructor-infected adult worker bees of A. mellifera ligustica were 1.7676 and 1.9929-fold as high as those of the healthy adult worker bees, respectively. 【Conclusion】 V. destructor infection can directly affect the respiratory metabolism of A. mellifera ligustica workers, leading to the disorder of their normal metabolic pathway, and seriously damaging the normal growth and development of bee colonies.

Antibacterial activity of BmPGRP-S5 of Bombyx mori and its role in cellular immunity

CHEN Xue, ZHOU Hong, LI Xiao-Feng, XIAO Yang, ZHONG Yang-Jin, YANG Wan-Ying

2020, 63(11): 1333-1344. doi:10.16380/j.kcxb.2020.11.006

Abstract ( 23 )

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【Aim】 Peptidoglycan-recognition proteins (PGRP) can specifically recognize peptidoglycan (PGN) in bacterial cell walls, and trigger the production of antimicrobial peptides through the immune deficiency (IMD) pathway and Toll pathway in insects. This study aims to explore the antibacterial activity of the Bombyx mori PGRP-S5 (BmPGRP-S5) and its function in initiating the cellular immunity in B. mori. 【Methods】 BmPGRP-S5 protein was expressed in Drosophila embryonic S2 cell line. The antibacterial activities of BmPGRP-S5 protein to Escherichia coli K₁₂D₃₁, Staphylococcus aureus and Bacillus megaterium were assayed based on the bacterial growth curve. The binding ability of BmPGRP-S5 protein to bacterial cell wall components of E. coli, S. aureus and Bacillus subtilis was detected by ELISA. The effect of BmPGRP-S5 on the activation of prophenoloxidase (PPO) by bacterial cell wall components was analyzed by measuring the absorbance value and observing the hemolymph melanization reaction of B. mori. The effect of BmPGRP-S5 on the
phagocytosis to bacteria by B. mori hemocytes was detected by fluorescein isothiocyanate isomer (FITC) labeling method. 【Results】 The expressed and purified BmPGRP-S5 protein was obtained. BmPGRP-S5 had no antibacterial effect on S. aureus, E. coli K₁₂D₃₁ and B. megaterium. However, after adding 40 μmol/L Zn²⁺, the antibacterial effect of BmPGRP-S5 protein on B. megaterium was significantly enhanced. The ELISA results showed that the binding ability of BmPGRP-S5 with PGN from S. aureus and lipoteichoic acid (LTA) from B. subtilis was strong, which also promoted the activation of phenoloxidase in B. mori hemolymph by these two bacterial cell wall components. The melanization reaction of B. mori hemolymph mediated by cell wall components was accelerated by BmPGRP-S5. After adding BmPGRP-S5 protein, the phagocytic rates of B. mori hemocytes to S. aureus, E. coli K₁₂D₃₁and B. megaterium increased to about 53.33%, 25.83%, and 30.83%, respectively, which were significantly higher than those of the control groups. 【Conclusion】 The antibacterial activity of BmPGRP-S5 is dependent on Zn²⁺ and may be related to its amidase activity. BmPGRP-S5 can play a role in melanization and phagocytosis in B. mori by recognizing bacterial cell wall components PGN or LTA. The BmPGRP-S5 protein used in this study was obtained by the recombinant expression in Drosophila S2 cells and can more truly display its functional activity in the physiological state of insects. Therefore, the results are instructive for the further development and utilization of BmPGRP-S5.

Elongation of genic untranslated regions, exploration of SSR loci and identification of unannotated genes and transcripts based on the nanopore sequencing dataset of Ascosphaera apis

DU Yu, FU Zhong-Min, ZHU Zhi-Wei, WANG Jie, FENG Rui-Rong, WANG Xiu-Na, JIANG Hai-Bin, FAN Yuan-Chan, FAN Xiao-Xue, XIONG Cui-Ling, ZHENG Yan-Zhen, XU Guo-Jun, CHEN Da-Fu, GUO Rui

2020, 63(11): 1345-1357. doi:10.16380/j.kcxb.2020.11.007

Abstract ( 21 )

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【Aim】 This study aims to improve the annotation information of the current reference genome of Ascosphaera apis by utilizing previously gained nanopore long-read sequencing data, and to identify and perform functional annotation of unannotated novel genes and novel transcripts. 【Methods】 Based on the previously gained nanopore long-read sequencing data, full-length transcripts of A. apis were compared with transcripts annotated in the reference genome using gffcompare software to prolong untranslated regions (UTRs). The open reading frames (ORFs) of genes in A. apis and their corresponding amino acid sequences were predicted using TransDecoder software. MISA software was used to survey simple sequence repeat (SSR) loci within transcripts with a length above 500 bp. Based on Blast tool, novel genes and novel transcripts were aligned to the Nr, KOG, eggNOG, Swiss-Prot, Pfam, GO and KEGG databases to gain their corresponding functional annotations. 【Results】 Totally, UTRs of 9 481 genes in A. apis were prolonged, among which 4 744 and 4 737 genes were prolonged at 5′UTR and 3′UTR, respectively. In addition, 10 492 complete ORFs were predicted, among which the ORFs encoding proteins distributed in 0-100 aa and 100-200 aa in length were the most abundant, accounting for 38.96% and 36.90% of the total ORFs, respectively. A total of 5 286 SSRs were identified, and the numbers of mononucleotide repeats, dinucleotide repeats, trinucleotide repeats, tetranucleotide repeats, pentanucleotide repeats and hexanucleotide repeats were 1 870, 826, 2 398, 138, 43 and 11, respectively. Besides, 1 558 novel genes were identified, among which 1 556, 731, 330, 592, 1 177, 709 and 589 were annotated to the Nr, Swiss-Prot, Pfam, KOG, eggNOG, GO and KEGG databases, respectively. Additionally, 14 403 novel transcripts were identified, among which 14 376, 8 524, 7 276, 7 405, 12 035, 7 891 and 6 855 were respectively annotated to the aforementioned seven databases. 【Conclusion】 By using the previously obtained nanopore long-read sequencing data, the complete ORFs of genes in A. apis has been predicted, the UTRs of annotated genes in reference genome have been elongated, the SSR loci have been explored, and a number of unannotated novel genes and novel transcripts have been identified and their functions annotated. These findings well improve the current genome annotation of A. apis, and offer a basis for further study on its omics and molecular biology.

Effects of temperature on the activities of respiratory metabolism-related and antioxidant enzymes in adults of Oedaleus asiaticus (Orthoptera: Acridoidea)

GUO Na, GAO Shu-Jing, WANG Ning, HAN Hai-Bin, XU Lin-Bo, DONG Rui-Wen, Narenmanduhu, Nabuqiya

2020, 63(11): 1358-1365. doi:10.16380/j.kcxb.2020.11.008

Abstract ( 24 )

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【Aim】 To elucidate the high temperature tolerance of Oedaleus asiaticus and the effect of temperature on the activities of respiratory metabolism-related and antioxidant enzymes in O. asiaticus adults. 【Methods】 Adults of O. asiaticus were exposed to nine temperature treatments in the range of 18-42℃ at 3℃ intervals under dark conditions in light incubator for 4 h and then recovered at room temperature for 1 h. The activities of respiratory metabolismrelated enzymes glyceraldehyde-3-phosphate dehydrogenase (GAPDH), glycerol-3-phosphate dehydrogenase (GPDH), 3-hydroxyacyl-CoA dehydrogenase (HOAD) and citrate synthase (CS), and antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in the adults of all the treatments were determined by biochemical method. 【Results】 The activities of the seven respiratory metabolismrelated and antioxidant enzymes in O. asiaticus adults assayed in the experiment increased first and then decreased with the temperature increasing. The activities of GAPDH, GPDH, HOAD and CS were the highest at 33, 27, 33 and 39℃, respectively, while those of SOD, CAT and POD were the highest at 30℃. The activities of all the tested seven enzymes were the lowest at 18℃. There was significant difference in the enzyme activities between female and male adults at most tested temperatures. The ratios of GAPDH activity to HOAD activity in female and male adults ranged from 1.99 to 3.31 at different temperatures, suggesting that the main carbohydrates are consumed in the respiratory metabolism of O. asiaticus. 【Conclusion】 In the tested temperature range of 18-42℃, the activities of respiratory metabolism-related enzymes and antioxidant enzymes in O. asiaticus adults first increase and then decrease with the increasing of temperature, and O. asiaticus adults adapt to temperature change by regulating the activities of respiratory metabolism-related and antioxidant enzymes.

Impact of transgenic herbicide-resistant soybean on the diversity of arthropods and weeds in soybean fields

CHEN Yan-Jun, LIU Lai-Pan, GUAN Xiao, LIU Biao

2020, 63(11): 1366-1376. doi:10.16380/j.kcxb.2020.11.009

Abstract ( 27 )

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【Aim】 With the increasing of planting areas of transgenic crops, more and more attention has been paid to the ecological security issues. The study of the impact of the transgenic crops on biodiversity is not only an important component for the environmental release of transgenic crops, but also an important tool to objectively evaluate their risks. This study aims to analyze the impacts of herbicideresistant soybean on the diversity of arthropods and weeds in soybean fields. 【Methods】 From June to September 2019, we investigated the number of arthropods (the number of insects per 100 plants) and their diversity indexes (Margalef index, Shannon-Wiener index, Simpson index, dominance concentration index and Pielou index), the species and quantity of pests and natural enemies, and the density, species, quantity and diversity indexes of weeds in soybean fields planted with soybean cultivars of four treatments, i.e., the herbicide-resistant transgenic g10-epsps soybean ZUTS-33 developed in China, the receptor soybean Huachun 3 (HC-3) and the main soybean cultivar Zhonghuang 13 (ZH-13) sprayed with water, and the transgenic soybean ZUTS-33 sprayed with the glyphosate herbicide Roundup (3 000 mL/hm²), respectively, in Hefei, Anhui Province, eastern China. 【Results】 In the early and middle growth stages of soybean in 2019, the numbers of insects per 100 plants in the four treatments exhibited similar changing trends except that the number of insects per 100 plants in the treatment of ZUTS-33 sprayed with water on August 13 was significantly lower than those in the other three treatments. The number of arthropods and their various diversity indexes showed no significant difference among the four treatments at the early and middle growth stages of soybean, and the numbers of six pest groups including whiteflies, aphids, thrips, leaf beetles, leafhoppers and Helicoverpa armigera and the numbers of six natural enemy groups including spiders, ladybirds, lacewing, flower bugs, plant bugs and Anomis flava showed similar dynamics among the four treatments during the investigation period. There were 10 weed species belonging to 8 families in the investigated soybean fields. The density and number of weeds in the treatment of ZUTS-33 sprayed with Roundup were significantly lower than those in the other three treatments, and their Margalef index, Shannon-Wiener index, Simpson index, and Pielou index in the treatment of ZUTS-33 sprayed with Roundup were significantly different from those in the other three treatments at the late growth stage of soybean. 【Conclusion】 The planting of the herbicide-resistant transgenic g10-epsps soybean ZUTS-33 has no significant effect on the diversity of arthropods and weeds in soybean fields.

Analysis of the genetic differentiation among geographical populations of Luehdorfia chinensis chinensis (Lepidoptera: Papilionidae) based on mitochondrial gene and nuclear genes

XIANG Ying, DONG Wan-Wei, JIANG Guo-Fang, HONG Fang, ZHANG You-Xiang, ZHANG Wen-Wu

2020, 63(11): 1377-1384. doi:10.16380/j.kcxb.2020.11.010

Abstract ( 30 )

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【Aim】 To investigate the genetic differentiation of geographical populations of Luehdorfia chinensis chinensis. 【Methods】 The mitochondrial COI gene and the non-coding fragments of three nuclear genes (ITS2, Pgi-intron and Tpi-intron) of 60 individuals from five geographical populations of L. chinensis chinensis were amplified by PCR. The genetic variation, genetic diversity and genetic differentiation of the five geographical populations were analyzed by using MEGA, DnaSP and Arlequin software, and their demography was inferred. 【Results】 The base sequences of the mitochondrial gene COI and the non-coding fragments of the three nuclear genes ITS2, Pgi-intron and Tpi-intron of the geographical populations of L. chinensis chinensis have strong AT bias. The nucleotide diversity index (π) and the average number of nucleotide differences (K) of the total population were 0.00686 and 18.289, respectively, indicating a high genetic diversity of the total population. The total fixed coefficient (Fst) and the total gene flow (Nm) were 0.4910 and 0.2600, respectively, suggesting that the genetic differentiation among geographical populations is large and the gene communication infrequent. The analysis of molecular variance (AMOVA) showed that the genetic differentiation of L. chinensis chinensis mainly came within a population (52.79%). The Mantel test showed that the geographical distance between populations had a significant positive correlation with the genetic distance (R=0.8519, P<0.05). 【Conclusion】 The five geographical populations of L. chinensis chinensis tested in this study exhibit high genetic diversity, and there are obvious genetic differentiation and little gene communication among the geographical populations. Geographical distance is one of the important factors affecting genetic differentiation among the geographical populations of L. chinensis chinensis. The total population of L. chinensis chinensis has not experienced any recent population expansion.

Ultrastructure of sensilla on the antennae, proboscis and tarsi of adult Achelura yunnanensis (Lepidoptera: Zygaenidae)

LI Gen-Ceng, ZHAO Yu-Jie, LI Jia-Li, LU Guo-Yan, LIU Nai-Yong

2020, 63(11): 1385-1398. doi:10.16380/j.kcxb.2020.11.011

Abstract ( 33 )

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【Aim】 This study aims to ascertain the types and differences of sensilla on the main chemosensory organs, including the antennae, proboscis and tarsi, of female and male adults of Achelura yunnanensis, so as to lay a basis for further studies associated with chemosensory reception of this moth. 【Methods】 The morphological characteristics of the antennae, proboscis and tarsi of female and male adults of A. yunnanensis and the types and ultrastructure of sensilla on them were observed under light microscopy and scanning electron microscopy. 【Results】 Seventeen subtypes of seven types of sensilla were identified on female and male antennae of A. yunnanensis adults, including five sensilla basiconica (SB), three sensilla trichodea (ST), three sensilla chaetica (SCH), two Bhm bristles (BB), two sensilla coeloconica (SCO), one sensilla auricillica (SAU) and one sensilla squamiformia (SSQ). Among them, BBI is present only on male antennae, and ST-II, ST-III and SCO-I show sexual dimorphism in length. Five subtypes of two types of sensilla were identified on female and male proboscises, including four SB and one SCH. Of these sensilla, SB-III is distributed only on female proboscis. In addition, 13 subtypes of five types of sensilla were found on female and male tarsi, including four ST, four SB, two SSQ, two BB and one SCH. Notably, ST-I is present only on female tarsi, while SB-II and SB-III are present only on male tarsi. The lengths of SB-IV and BB-I on female and male tarsi show sexual dimorphism. 【Conclusion】 There are 17, 5 and 13 subtypes of sensilla on the antennae, proboscis and tarsi of female and male adults of A. yunnanensis, respectively. Some of these sensilla exhibit sexual dimorphism in the type, length or number.

Research progress in ionotropic receptors and their functions in insects

GUO Jin-Meng, DONG Shuang-Lin

2020, 63(11): 1399-1410. doi:10.16380/j.kcxb.2020.11.012

Abstract ( 35 )

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As the largest group in the animal kingdom, insects have evolved complex sensory systems in response to various environmental stimuli, in which the chemosensation (olfaction and gustation) is the most important. The odorant receptors (ORs) and gustatory receptors (GRs) play a key role in olfaction and gustation, respectively. However, in recent years, it has been found that ionotropic receptors (IRs) are also involved in chemosensation as well as non-chemosensation such as sensation of temperature and humidity. The IR family is evolved from ionotropic glutamate receptors (iGluRs) which contain three typical transmembrane domains. Similar to ORs, each IR needs to be co-expressed with at least one of the four identified co-receptors (IR8a, IR25a, IR76b and IR93a) for its normal function. Two or more IRs can be co-expressed in a same olfactory neuron, and different IR combinations lead to their different response profiles in neurons. One insect species usually contains several to over one hundred IRs, with some IRs showing antennaespecific expression patterns, but most IRs remaining unknown in the function and the mechanism of action. In this article, the research advances in the structure and evolution of IRs, and the identification, expression and function of IR genes in insects were reviewed, hoping to provide some references for the further studies on the function and mechanisms of action of IRs, and the potential use of insect IRs as targets in pest control.

Advances in landscape genomics and its application in integrated pest management

CHEN Yan-Ting, YOU Shi-Jun, KE Fu-Shi, LIU Tian-Sheng, LI Jian-Yu, YOU Min-Sheng

2020, 63(11): 1411-1430. doi:10.16380/j.kcxb.2020.11.013

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The recent development of novel sequencing technologies and bioinformatics has greatly facilitated the fundamental and applied studies on insect genomes with the steady increase of accomplishments. Studies that integrate variables of agricultural landscape with the genomic structure, genetically adaptive variation, and gene functions aid in better understanding of the molecular mechanisms associated with the adaptability and infestation of a target pest in a specific landscape framework, providing new thoughts and directions for pest management. Landscape genomics is an interdisciplinary subject combining landscape ecology with population genomics and aims to examine the genetic basis of adaptation of a given species to changing environments. Landscape genomics mainly focus on the investigation and analysis of adaptive evolution in species as well as gene flow and genetic drift among populations that are under environmentassociated selection. The research methodology of landscape genomics can be generalized as the design of spatial sampling strategy, utilization of molecular markers, and data collection and analysis. In this article we reviewed the research status of landscape genomics including the major findings and achievements in recent years. Further, we elaborated the application and prospects of landscape genomics in the aspects of insecticide resistance management, conservation biological control, and integrated pest management in the context of global climate change, with the ultimate goal of reducing the use of insecticides and promoting the safe production of crops.

Contents of Vol. 63 Issue 11

2020, 63(11): 1430-1430.

Abstract ( 13 )

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