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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
Table of Content
20 February 2020, Volume 63 Issue 2
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  • INTRODUCTION
    Plant pathogen-insect vector interactions: research progress and prospects
    YAN Feng-Ming
    2020, 63(2):  123-130.  doi:10.16380/j.kcxb.2020.02.001
    Abstract ( 794 )   PDF (1449KB) ( 616 )   PDF(mobile) (1449KB) ( 110 )     
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     Most plant viruses and some plant pathogenic bacteria are transmitted by insect vectors. Understandings on plant pathogen-insect vector interactions can facilitate the recognition of key issues in effective management of plant pathogens and their vectors. Therefore, pathogen-vector interaction has become one of the core topics in the studies of pathogen transmission mechanisms. This article reviewed the recent research progress in plant pathogen-insect vector interactions, introduced the main contents of papers in this issue, and based on them proposed the following three directions for future research from ecological and evolutionary perspectives: (1) the roles of the interactions between plant pathogens and insect vectors in reshaping ecological systems; (2) the inter-relationships between different modes of plant virus transmission by insect vectors, and issues related to co-evolution among viruses, vectors and plants; and (3) the mechanisms of interactions between plant pathogens and insect vectors in nature. Studies on plant pathogen-insect vector interactions are not only fundamentals in ecology and evolutionary biology, but closely related to effective management of plant pathogens and their insect vectors as well.
    RESEARCH PAPERS
    Identification of the IKK related genes and their antiviral roles in response to Rice stripe virus infection in Laodelphax striatellus (Hemiptera: Delphacidae)
    LU Yan-Hua, LU Gang, QI Yu-Hua, YE Zhuang-Xin, LI Jun-Min, CHEN Jian-Ping
    2020, 63(2):  131-141.  doi:10.16380/j.kcxb.2020.02.002
    Abstract ( 788 )   PDF (2733KB) ( 144 )   PDF(mobile) (2733KB) ( 40 )     
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    【Aim】 This study aims to identify the IκB kinase (IKK) related genes in the small brown planthopper, Laodelphax striatellus, and to investigate its antiviral role in this insect, so as to further understand the innate immune mechanisms in insect vectors responsive to plant viruses. 【Methods】 The IKK related genes in the L. striatellus genome were identified and characterized using bioinformatics approach. The healthy and the rice stripe virus (RSV) infected planthopper were used as the materials. The expression levels of IKK related genes in various developmental stages (egg, 1-5 instar nymphs, male and female adults) and adult tissues (gut, salivary gland, hemolymph, fat body, ovary and testis) of the RSV-free planthoppers were detected by RT-PCR. The relative expression levels of IKK related genes in the above different developmental stages and adult tissues between the RSV-free and RSV-infected planthoppers were assayed by qRT-PCR. In addition, the transcription levels of coat protein (CP) gene indicating the accumulation levels of RSV were determined after RNAi by injection of the double-stranded RNA of IKK related genes in the 3rd instar nymph of RSV-infected planthoppers. 【Results】 Two IKK related genes, IKKα (GenBank accession number: MK903504) and TANK-binding kinase 1 gene TBK1 (GenBank accession number: MN124506), were identified in the genome of L. striatellus. The open reading frame (ORF) of IKKα is 2 379 bp in length, encoding 792 amino acids, while the ORF of TBK1 is 1 551 bp in length, encoding 516 amino acids. The proteins coded by both genes have a conserved serine/threonine kinase domain and a ubiquitin folding domain. The RT-PCR results confirmed that IKKα and TBK1 were ubiquitously expressed in various developmental stages and different adult tissues of RSV-free L. striatellus. Significant expression differences of IKKα and TBK1 in various developmental stages and different adult tissues between the RSV-free and RSV-infected planthoppers were observed. The accumulation level of RSV was significantly increased after RNAi of IKKα and TBK1 in the 3rd instar nymphs of the RSV-infected planthoppers, respectively. 【Conclusion】 The results indicate that IKKα and TBK1, the important genes of NF-κB signaling pathway, are widely expressed in L. striatellus and may play important roles in L. striatellus in response to RSV invasion. These results will contribute to the further investigation on antiviral immune pathway in insect vectors against plant virus.
    RNAi of the calcium-binding protein gene and its biological effects in Bemisia tabaci MED (Hemiptera: Aleyrodidae)
    GUO Lei, PAN Zheng-Yuan, LIU Jia-Yin, HAN Ming-Xuan, CHU Dong
    2020, 63(2):  142-148.  doi:10.16380/j.kcxb.2020.02.003
    Abstract ( 666 )   PDF (1188KB) ( 131 )   PDF(mobile) (1188KB) ( 41 )     
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    【Aim】 Our previous study revealed that two calcium-binding proteins (BtCaBP1 and BtCaBP2) are involved in the stress response of Bemisia tabaci MED to cyantraniliprole. This study aims to systematically reveal the biological effects of calcium-binding proteins on B. tabaci MED by RNAi of their genes. 【Methods】 After knocking down the calcium-binding protein genes BtCaBP1 and BtCaBP2 in B. tabaci MED adults by feeding dsRNA, the expression levels of the two genes were determined by qPCR. The biological parameters including the longevity (female and male) and fecundity of adults, and the egg hatching rate and pre-adult duration of offspring of B. tabaci MED between the control group (feeding on dsEGFP) and the treatment group (feeding on dsBtCaBP1 and dsBtCaBP2, respectively) were observed and compared after RNAi for 3 d. 【Results】 After feeding on dsBtCaBP1 and dsBtCaBP2, respectively, for 3 d, the expression levels of the target genes BtCaBP1 and BtCaBP2 of B. tabaci MED adults decreased significantly as compared with those in the control group. Compared with the control group, the dsBtCaBP2 treated-group had significantly increased the longevity (female: 15.46±1.24 d vs 13.25±0.58 d; male: 13.84±0.38 d vs 12.67±0.65 d), significantly decreased the number of eggs laid per female (39.53±3.04 vs 76.06±4.76), significantly decreased the egg hatching rate of offspring (81.58%±4.42% vs 87.22%±3.21%), and significantly shortened the pre-adult duration of offspring (24.42±1.09 d vs 27.52±1.73 d). However, feeding on dsBtCaBP1 had no significant effect on the above biological parameters of B. tabaci MED. 【Conclusion】 The RNAi of BtCaBP1 and BtCaBP2 has different biological effects on B. tabaci MED, and this finding will be helpful to reveal the function of CaBPs.
    Primer screening and amplification protocol optimization of rapid detection technique for Cucurbit chlorotic yellows virus
    WANG Ke, HE Yan-Yan, ZHANG You-Jun, WU Qing-Jun, WANG Shao-Li
    2020, 63(2):  149-158.  doi:10.16380/j.kcxb.2020.02.004
    Abstract ( 471 )   PDF (5036KB) ( 71 )   PDF(mobile) (5036KB) ( 12 )     
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    【Aim】 Cucurbit chlorotic yellows virus (CCYV) is an emerging plant virus, in semi-persistent manner, transmitted by the sweetpotato whitefly, Bemisia tabaci. Induced virus disease by CCYV has caused severe economic losses to cucurbit crops. CCYV monitoring based on PCR method is a common technique for detecting this virus. However, some commonly used primers have the problems of unstable amplification results and insufficient reproducibility. This study aims to screen and obtain the more suitable primers for stable detection of CCYV under optimized conditions. 【Methods】 The bacterial liquid of Agrobacterium tumefaciens strain GV3101 carrying CCYV and the cDNA from its infected cucumber leaves were amplified by PCR with 14 pairs of primers known currently to screen primers for stable detection of CCYV. The annealing temperatures were also optimized. Using the cDNA from cucumber leaves infected by A. tumefaciens carrying CCYV, the stability and sensitivity of the selected four primer pairs in PCR amplification were determined. Then, the CCYV infection of 13 samples including B. tabaci adults and host plant leaves collected from the field was detected and validated by the selected primers and the optimized amplification procedure. 【Results】 Four pairs of primers were screened out from the 14 known primer pairs, which could stably amplify cDNA from A. tumefaciens carrying CCYV and its infected cucumber leaves, and the optimized amplification procedure was obtained. Sensitivity test revealed that the minimum cDNA concentration of CCYV-infected cucumber leaves in PCR assay with the selected four pairs of primers was 0.25 ng/μL. Detection results of CCYV infection in 13 samples including B. tabaci adults and host plant leaves collected from the field by PCR with the selected four pairs of primers showed that 69.23% samples were CCYV positive. 【Conclusion】 The selected four pairs of primers and the corresponding optimized amplication procedure could be applied for accurate detection of CCYV in A. tumefaciens carrying CCYV, CCYV-infected plant leaves and field samples.
    Development and application of a TaqMan real-time fluorescent quantitative PCR method for rapid detection of Tomato chlorosis virus
    WANG Ji-Cheng, LI Jie, DING Tian-Bo, CHU Dong
    2020, 63(2):  159-165.  doi:10.16380/j.kcxb.2020.02.005
    Abstract ( 552 )   PDF (2084KB) ( 51 )   PDF(mobile) (2084KB) ( 13 )     
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    【Aim】 The aim of this study is to develop a TaqMan real-time fluorescent quantitative PCR (TaqMan RT-qPCR) method to rapidly detect the tomato chlorosis virus (ToCV) in a single whitefly (Bemisia tabaci) vector. 【Methods】 A pair of specific primers and one TaqMan probe were designed based on the conserved sequence of ToCV coat protein, and then TaqMan RT-qPCR was developed for viral detection. The sensitivity and specificity of TaqMan RT-qPCR were compared to those of the conventional PCR. Finally, this method was applied to rapidly detect ToCV in a single adult of B. tabaci. 【Results】 The cycle threshold (Ct) on the standard curve of TaqMan RT-qPCR of ToCV showed a linear relationship with the template concentration, and the amplification efficiency was 98%. The minimum concentration of this virus detection method was 8.3×10 copies/μL, and the sensitivity was 1 000 times as high as that of the conventional PCR. This method had no cross-reactivity with two important tomato viruses in the field, i.e., tomato yellow leaf curl virus (TYLCV) and tomato spotted wilt virus (TSWV). Detection of ToCV in a single adult of B. tabaci showed that the viruliferous rate of ToCV in B. tabaci in greenhouses was 100% and that in the field was 30%. 【Conclusion】 The TaqMan RT-qPCR method developed in this study can detect ToCV in a single whitefly (B. tabaci) rapidly and efficiently, providing technical support for the prevention and control of this virus disease.
    Comparison of feeding behaviors and pathogen acquisition rates of adults and the 5th instar nymphs of Diaphorina citri (Hemiptera: Liviidae) on huanglongbing-infected citrus plants
    WU Tian-Yu, ZHANG Xu-Ying, George A. C. BEATTIE, CEN Yi-Jing
    2020, 63(2):  166-173.  doi:10.16380/j.kcxb.2020.02.006
    Abstract ( 742 )   PDF (1548KB) ( 110 )   PDF(mobile) (1548KB) ( 35 )     
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    【Aim】 The Asiatic citrus psyllid (ACP), Diaphorina citri, is the major vector of ‘Candidatus Liberibacter asiaticus’ (‘CLas’) (α-Proteobacteria), the pathogen that causes the Asiatic form of huanglongbing (HLB), the most devastating disease of citrus. The aims of this study are to determine whether the feeding behaviors of adults and the 5th instar nymphs of D. citri differ, and if so, whether these differences influence pathogen acquisition efficiency, and whether HLB-infected plants influence feeding by the 5th instar nymphs. 【Methods】 The feeding behavior of adults and the 5th instar nymphs of D. citri on immature shoots of HLB-infected Citrus reticulata cv. Sunki was recorded for 10 h with DC-EPG giga-4. The acquisition efficiency of the pathogen by individual adults and nymphs from HLB-infected shoots was determined by qPCR. The feeding behaviors of the 5th instar nymphs on pathogen-free and HLB-infected shoots were also recorded and compared by EPG. 【Results】 The feeding behaviors of adults and the 5th instar nymphs of D. citri on C. reticulata cv. Sunki shoots infected with HLB differed significantly. The 5th instar nymphs started to ingest xylem and phloem sap sooner than adults. Durations of the phloem salivation and ingestion phases of nymphs were significantly longer than those of adults. When feeding on HLB-infected shoots, 37.5% of the 5th instar nymphs acquired ‘CLas’ in contrast 20% of adults. The frequencies of probing and salivation and phloem sap ingestion by the 5th instar nymphs feeding on HLB-infected shoots were significantly lower than those on healthy shoots. However, HLB-infected plants did not influence the duration of phloem salivation and sap ingestion by the 5th instar nymphs. Feeding also commenced sooner in phloem of HLB-infected shoots than in phloem of healthy shoots. 【Conclusion】 The 5th instar nymphs of D. citri feed for longer intervals, ingest more phloem sap, and acquire higher titers of ‘CLas’ than adults. This may be due to that nymphs require more nutrients for their growth and development than adults. They are therefore less inclined to withdraw their stylets from, and re-insert their stylets into ‘CLas’-infected leaf tissues. ‘CLas’-induced changes in host-plant phytochemistry promote feeding by the 5th instar nymphs of D. citri.
    Effects of Rice stripe mosaic virus on the growth, reproduction and feeding behavior of the vector Recilia dorsalis (Hemiptera: Cicadellidae)
    LI Pan, ZHANG Jie, YUE Yue, CHEN Hong-Yan, WU Wei, WEI Tai-Yun, JIA Dong-Sheng
    2020, 63(2):  174-180.  doi:10.16380/j.kcxb.2020.02.007
    Abstract ( 492 )   PDF (1444KB) ( 101 )   PDF(mobile) (1444KB) ( 15 )     
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    【Aim】 Rice stripe mosaic virus (RSMV) transmitted by the leafhopper Recilia dorsalis has caused severe rice damage in southern China. This study aims to evaluate the effects of RSMV on the growth, reproduction and feeding behavior of the vector R. dorsalis. 【Methods】 The growth and life table parameters of R. dorsalis infected by RSMV were assayed by laboratory breeding experiments, and the feeding behavior of the nonviruliferous and viruliferous R. dorsalis on healthy rice plants was measured by the electrical penetration graph (EPG) technique. Finally, the host plant preference of R. dorsalis to RSMV-free and RSMV-infected rice plants was determined with Y-shaped olfactometer. 【Results】 When the R. dorsalis nymphs were infected with RSMV, the nymphal duration of viruliferous R. dorsalis was prolonged, while the nymphal survival rate, adult emergence rate, female fecundity and egg hatching rate were reduced as compared with those of the nonviruliferous R. dorsalis. In addition, the nonviruliferous R. dorsalis adults preferred RSMV-infected rice plants to RSMV-free rice plants, while the viruliferous R. dorsalis adults preferred to select RSMV-free rice plants rather than select RSMV-infected rice plants. The viruliferous R. dorsalis adults fed on RSMV-free rice plants had a higher number and longer duration of waveforms representing stylet puncture, penetration difficulties and salivation, and also exhibited a lower number and lengthened duration of waveforms representing phloem sap ingestion phase and resting behavior as compared to the nonviruliferous leafhoppers. 【Conclusion】 The infection of RSMV lengthens the nymphal duration of viruliferous R. dorsalis compared with nonviruliferous R. dorsalis and is unfavorable to the propagation of viruliferous population. RSMV manipulates the feeding and host selection behavior of R. dorsalis adults to facilitate viral transmission between rice plants.
    Changes in the nutrient composition of tobacco plants after Potato virus Y infection and their effects on the growth and development of the vector Myzus persicae (Hemiptera: Aphididae)
    CHEN Xi, LIU Jin-Yan, XU Peng-Jun, LIU Ying-Jie, DONG Yong-Hao, ZANG Yun, CAI Xian-Jie, REN Guang-Wei
    2020, 63(2):  181-190.  doi:10.16380/j.kcxb.2020.02.008
    Abstract ( 421 )   PDF (1692KB) ( 47 )   PDF(mobile) (1692KB) ( 6 )     
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    【Aim】 This study aims to evaluate the changes in nutrients in tobacco induced by potato virus Y (PVY) and their effects on the life characteristics of the green peach aphid, Myzus persicae, so as to clarify the interaction mechanism between PVY-tobacco and aphids. 【Methods】 Changes in the soluble sugar and free amino acid contents in tobacco plants at different stages of PVY infection were determined using the anthrone colorimetric method and an automatic amino acid analyzer, respectively. The differences in population development parameters, adult longevity, fecundity, and the number of alataes of M. persicae on PVY-infected tobacco plants and healthy tobacco plants were investigated and compared. 【Results】 The free amino acid contents in tobacco leaves at the early, steady, and late stages of PVY infection (5, 12 and 20 d post infection, respectively) were significantly higher than those in the healthy leaves. Moreover, the contents of glutamic acid, proline, aspartic acid, tryptophan, valine, lysine, and histidine in tobacco leaves at the early stage of PVY infection were also significantly higher than those in the healthy plants. Moreover, at the steady stage of PVY infection, the serine content in tobacco leaves was significantly decreased, whereas the contents of glutamic acid, aspartic acid, tryptophan, valine, leucine, phenylalanine, arginine, and histidine were significantly increased as compared with those in the healthy leaves. At the late stage of PVY infection, the glycine content in tobacco leaves was significantly decreased, whereas the contents of glutamic acid, proline, aspartic acid, threonine, valine, leucine, alanine, phenylalanine, histidine, tyrosine, and arginine were significantly increased as compared with those in the healthy leaves. Furthermore, the soluble sugar contents in tobacco leaves at the early and steady stages of PVY infection were significantly higher than that in the healthy leaves, but significantly lower at the late stage of infection. The content ratios of total sugars to total free amino acids in tobacco leaves at the early and steady stages of PVY infection were significantly higher than that in the healthy leaves. Analysis of life table data showed that there were no significant differences in the developmental duration, pre-adult duration, reproductive period, post-reproductive period, longevity, intrinsic rate of increase, finite rate of increase and mean generation time of M. persicae on the PVY-infected and healthy plants. However, as compared with the aphids on the healthy plants, the aphids on the PVY-infected plants had a significantly shorter pre-reproductive period, and significantly higher fecundity and net reproductive rate. The M. persicae population on the PVY-infected plants showed an advanced peak of alatae emergence relative to that on the healthy plants. 【Conclusion】 The nutritional quality of tobacco host is improved at the early and steady stages of PVY infection, thus improving the fecundity of M. persicae. However, the decline in the nutritional quality of tobacco plants at the late stage of infection might contribute to the earlier emergence and spread of the alataes, which is conducive to PVY transmission.
    Evaluation of laboratory toxicities of nC22 agricultural mineral oil and its mixture with imidacloprid against the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae)
    GAO Jing, YANG Qiong-Yu, FENG Yao-Heng, MAO Run-Qian
    2020, 63(2):  191-198.  doi:10.16380/j.kcxb.2020.02.009
    Abstract ( 805 )   PDF (1277KB) ( 72 )   PDF(mobile) (1277KB) ( 11 )     
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    【Aim】 The objective of this study is to evaluate the toxicities of nC22 mineral oil against the Asian citrus psyllid, Diaphorina citri, when used alone or mixed with imidacloprid in the laboratory, and to screen the mixing ratios that show synergistic effect on imidacloprid, so as to provide scientific support for the application of mineral oil against D. citri. 【Methods】 In the laboratory, the lethal effect of nC22 mineral oil and the positive controls nC23 and nC28 mineral oils against eggs, and the early instar nymphs, late instar nymphs, and adults of D. citri were determined by immersion method and spraying method, respectively, and the toxicities were calculated based on the LC50 values (7 d after treatment for eggs, and 1 d after treatment for nymphs and adults). The nC22 mineral oil was mixed with imidacloprid at various ratios, and their lethal effects on the early instar nymphs of D. citri were determined. The synergistic effect of nC22 mineral oil on imidacloprid was evaluated by interactive determination, co-toxicity factor (CTF), and co-toxicity coefficient (CTC) methods. 【Results】 When used alone, the LC50 value of nC22 mineral oil against D. citri eggs was significantly lower than those of nC23 and nC28 mineral oils. The LC50values of nC22 mineral oil against both the early and late instar nymphs were similar to those of nC23 mineral oil, and lower than those of nC28 mineral oil. The LC50 value of nC22 mineral oil against adults was similar to that of nC28 mineral oil, and lower than that of nC23 mineral oil. The mixtures of nC22 mineral oil and imidacloprid at the ratios of 3∶7, 4∶6 and 7∶3 showed remarkable synergistic effect on imidacloprid: the actual mortalities of the early instar nymphs of D. citri were above the equivalent line in the interactive determination method, the CTF value were 34.807, 22.655, and 40.798, and the CTC values were 187.430, 183.876 and 222.936, respectively. The mixture of nC22 mineral oil and imidacloprid at the ratio of 7∶3 showed the strongest synergistic effect on imidacloprid. 【Conclusion】 nC22 mineral oil shows higher toxicity against D. citri than the imported nC23 and traditional nC28 mineral oils. When mixed with imidacloprid at proper ratios, nC22 mineral oil shows strong synergistic effect, and theoretically it can significantly reduce the use of chemical insecticide, which could be further tested in fields.
    Effects of silicon amendment to rice on piercing and host selection behaviors of the white-backed planthopper, Sogatella furcifera (Hemiptera: Delphacidae)
    JIA Lu-Yao, LIU Dan-Dan, HOU Mao-Lin
    2020, 63(2):  199-206.  doi:10.16380/j.kcxb.2020.02.010
    Abstract ( 432 )   PDF (2822KB) ( 103 )   PDF(mobile) (2822KB) ( 18 )     
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    Aim】 Silicon (Si) amendment to plants can confer enhanced resistance to multiple herbivores. The study aims to understand the effects of Si amendment on silicification of rice leaf sheath and on piercing and host selection behaviors of the white-backed planthopper (WBPH), Sogatella furcifera, so as to identify Si-mediated rice resistance to WBPH. 【Methods】 Silicification of rice leaf sheath was observed using scanning electron microscope (SEM). The piercing behavior of WBPH nymphs was recorded with electrical penetration graph (EPG). The host selection and oviposition preference of female adults of WBPH were determined with cage test. 【Results】 Compared with the control plants without Si amendment, the rice plants amended with 0.16 or 0.32 g SiO2/kg soil were characterized by increased number of silica cells in the leaf sheaths. Si addition prolonged the non-probing event and pathway event and shortened the phloem ingestion event of WBPH nymphs. In the host selection tests, the settling preference of WBPH female adults for the rice plants amended with 0.16 and 0.32 g SiO2/kg soil decreased by 48.0% and 67.4%, respectively, than for the control plants, and the oviposition amount on these Si-amended plants decreased by 34.8% and 46.1%, respectively, than on the control plants. 【Conclusion】 Si amendment to rice plants enhances rice resistance to WBPH through increasing the antixenosis of rice to WBPH and impairing the piercing behavior of WBPH.
    Transcriptome analysis of differentially expressed genes in Monochamus alternatus (Coleoptera: Cerambycidae) carrying and without carrying pine wood nematode (Bursaphelenchus xylophilus)
    LI Ming-Yu, ZHOU Jiao, WANG Hai-Xiang, ZHAO Li-Lin
    2020, 63(2):  207-217.  doi:10.16380/j.kcxb.2020.02.011
    Abstract ( 489 )   PDF (2891KB) ( 106 )   PDF(mobile) (2891KB) ( 29 )     
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    【Aim】 The objective of this study is to establish the transcriptome database of adult tissues of the pine sawyer beetle, Monochamus alternatus, carrying and without carrying the pine wood nematode, Bursaphelenchus xylophilus, and to reveal the overall expression characteristics of M. alternatus in response to pine wood nematode. 【Methods】 The transcriptomes of epidermis, trachea and fat body of M. alternatus adults carrying and without carrying B. xylophilus were sequenced using the Illumina HiSeqTM 2000 platform, the transcriptome data were de novo assembled using Trinity software, and gene annotation was conducted by using the NCBI database. The differentially expressed genes in M. alternatus adults carrying and without carrying B. xylophilus were screened by DEG-Seq, and the up-regulated genes were subjected to GO and KEGG metabolic pathway enrichment analysis. The expression levels of some differentially expressed genes including ENV, CDK1, HSP70-C, HSP70, HSP75, DUO, PABPN1 and IGFP genes were verified by real-time quantitative PCR (RT-qPCR). 【Results】 After sequencing and filtering, a total of 55 059 unigenes were obtained with an average length of 1 536 bp. A total of 24 354 unigenes were annotated using BLASTX searches against the databases, of which 4 022 unigenes were assigned in GO database and 6 098 unigenes were assigned in the KEGG database. The enrichment analysis of GO and KEGG showed that the main differentially expressed genes in the trachea of M. alternatus adults carrying B. xylophilus are related with pressure regulation, tissue and DNA repair, and hormone response. The RT-qPCR analysis showed that the expression levels of CDK1, HSP70, HSP75, DUO, PABPN1, and IGFP genes were significantly higher in the trachea of M. alternatus carrying pine wood nematodes than in the trachea of M. alternatus without carrying pine wood nematodes. 【Conclusion】 This study preliminarily clarified the overall expression pattern of the transcriptome of M. alternatus carrying B. xylophilus, providing a foundation for further study of the gene function of M. alternatus and the stress response of M. alternatus to B. xylophilus.
    Genetic differences among geographical populations and rapid early detection of a nymphal parasitoid of Lycorma delicatula (Hemiptera: Fulgoridae)
    XIN Bei, Atif MANZOOR, CAO Liang-Ming, WANG Xiao-Yi
    2020, 63(2):  218-228.  doi:10.16380/j.kcxb.2020.02.012
    Abstract ( 675 )   PDF (7356KB) ( 152 )   PDF(mobile) (7356KB) ( 43 )     
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    【Aim】 This study aims to determine the genetic differences among parasitoids of Lycorma delicatula nymphs from different geographical populations, and to rapidly identify the parasitism of parasitoids on L. delicatula nymphs at the early parasitization stage so as to evaluate the control effects of parasitoids on L. delicatula populations. 【Methods】 The DNA barcoding method was used to sequence COI and 28S rDNA genes of parasitoids of L. delicatula nymphs from different geographical populations. The genetic distances between the parasitoids from different geographical populations were calculated using K2P model, and a phylogenetic tree was constructed using neighbor-joining (NJ) method. The species-specific PCR (SS-PCR) primers were designed to determine whether L. delicatula was parasitized by Dryinus sinicus by amplification of DNA from L. delicatula nymphs using SS-PCR method. Visual assessment method and SS-PCR amplification were used to determine the parasitism rates of the parasitoids on L. delicatula nymphs from different sampling localities. 【Results】 The parasitoids of L. delicatula nymphs were identified as D. sinicus. A total of 16 haplotypes and four haplotypes were detected in COI and 28S rDNA sequences of D. sinicus from different geographical populations, respectively. The genetic distance among D. sinicus from different geographical populations was 0.00691-0.01310. The phylogenetic tree constructed by NJ method showed that D. sinicus samples from different geographical populations were clustered in one branch. SS-PCR primers based on COI sequence could produce good amplification results for both adult and larva of D. sinicus, with the detection threshold of 0.000005 ng/μL DNA. The parasitism rates of D. sinicus on L. delicatula nymphs from different sampling localities were 22.54%-60.00% detected by SS-PCR, significantly higher than those by visual assessment method (5.63%-36.98%). 【Conclusion】 The genetic differences of D. sinicus from different geographical populations are quite low. SS-PCR primers can be used for rapid detection of the early parasitism of L. delicatula by D. sinicus.
    REVIEW ARTICLES
    Wing morph differentiation of plant-pathogen borne vector insects  
    YU Jin-Ting, CHEN Xiao-Fang, REN Ying-Dang, CUI Feng
    2020, 63(2):  229-234.  doi:10.16380/j.kcxb.2020.02.013
    Abstract ( 772 )   PDF (1085KB) ( 143 )   PDF(mobile) (1085KB) ( 26 )     
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    Wing polymorphism is one of insect polyphenism phenomena, including short-winged or apterous morph without flight ability and long-winged or alate morph for long distance migration. Wing polymorphism is often observed in vector insects that transmit plant pathogens, and therefore affects the spatial-temporal distribution and outbreak of plant diseases. In this article we reviewed the research progress of wing dimorphism in aphids and planthoppers from the genetic laws, induction factors, molecular mechanisms, and other physiological modification accompanying wing morph differentiation. Wing dimorphism is mainly induced by abiotic factors, such as temperature, humidity and photoperiod, and biotic factors, such as population density, host nutrition and viruses. The underlying molecular mechanisms are involved in the insulin/insulin-like growth factor signaling (IIS) pathway, c-Jun NH2-terminal kinase (JNK) signaling pathway, Wingless and olfactory receptor SaveOrco. Wing morph differentiation of insects is accompanied by changes in physiological status. The short-winged insects have stronger reproduction ability, while the long-winged insects contain richer flight muscle components. So far, the research of wing dimorphism is not comprehensive, and many problems need to be solved, such as identifying the target genes in the insulin/insulin-like growth factor signaling pathway, the regulation mechanisms of JNK on wing dimorphism and the molecular mechanisms of wing dimorphism mediated by viruses in vector insects. This review may shed light on the control of vector-borne pathogens and the research of wing polymorphism of other insects.
    Honeydew excretion mechanisms in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae): progress and prospects
    SHU Ben-Shui, WU Zhong-Zhen, CUI Yang, LIN Jia-Hao, LIN Jin-Tian
    2020, 63(2):  235-244.  doi:10.16380/j.kcxb.2020.02.014
    Abstract ( 756 )   PDF (1960KB) ( 112 )   PDF(mobile) (1960KB) ( 32 )     
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    The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is a general pest causing economic losses in orchards, mainly feeds on the highly osmotic sap of citrus phloem and transmits pathogen Candidatus Liberibacter asiaticus to induce a devastating disease of citrus named huanglongbing (HLB). The osmotic pressure of phloem sap is a challenge for hemipteran insects, which is regulated by a set of osmoregulation mechanisms evolved in insects. The excessive sugars are converted into long chain oligosaccharides and excreted outside of insects as honeydew. In this article, the behavior of honeydew excretion, composition of honeydew and factors affecting honeydew excretion of D. citri are summarized, and the functions of osmoregulatory genes involved are overviewed. The studies show that the behavior of honeydew excretion and the color, texture and composition of honeydew were different among male and female adults and nymphs of D. citri. The host plants, insecticides, pathogenic microorganisms and compounds secreted by natural enemies were demonstrated as the main factors affecting the excretion behavior of D. citri. In addition, the pivotal osmoregulatory genes encoding α-glucoside hydrolases, aquaporins and sugar transporters were considered as the potential genes involved in the regulation of honeydew excretion. This review may provide a reference for further studying honeydew excretion behavior of D. citri and exploring the new targets for developing new insecticides for the control of this insect.
    CONTENTS
    Contents of Vol. 63 Issue 2
    2020, 63(2):  244-244. 
    Abstract ( 307 )   PDF (467KB) ( 26 )   PDF(mobile) (467KB) ( 4 )     
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