Recognition and differentiation of seven whitefly-transmitted geminiviruses from India, and their relationships to African cassava mosaic and Thailand mung bean yellow mosaic viruses

Particles resembling those of geminiviruses were found by immunosorbent electron microscopy in extracts of plants infected in India with bhendi yellow vein mosaic, croton yellow vein mosaic, dolichos yellow mosaic, horsegram yellow mosaic, Indian cassava mosaic and tomato leaf curl viruses. All these viruses were transmitted by Bemisia tabaci whiteflies, all reacted with at least one out of ten monoclonal antibodies to African cassava mosaic virus (ACMV), and all reacted with a probe for ACMV DNA-1, but scarcely or not at all with a full-length probe for ACMV DNA-2. Most of the viruses were distinguished by their host ranges when transmitted by whiteflies, and the rest could be distinguished by their pattern of reactions with the panel of monoclonal antibodies. Horsegram yellow mosaic virus was distinguished from Thailand mung bean yellow mosaic virus by its lack of sap transmissibility, ability to infect Arachis hypogaea, failure to react strongly with the probe for ACMV DNA-2 and its pattern of reactions with the monoclonal antibodies. Structures resembling a ‘string of pearls’, but not geminate particles, were found in leaf extracts containing malvastrum yellow vein mosaic virus. Such extracts reacted with two of the monoclonal antibodies, suggesting that this whitefly-transmitted virus too is a geminivirus. All seven viruses from India can therefore be considered whitefly-transmitted geminiviruses.     

Breeding for resistance to whitefly-transmitted geminiviruses

Geminiviruses comprise a large and diverse family of viruses that infect a wide range of important monocotyledonous and dicotyledonous crop species and cause significant yield losses. The family Geminiviridae is divided into three genera, one of which is Begomovirus. Species of this genus are transmitted by the whitefly Bemisia tabaci in a persistent, circulative manner and infect dicotyledonous plants. Severe population outbreaks of B. tabaci are usually accompanied by a high incidence of begomoviruses. During the last two decades, there has been a worldwide spread of the B biotype of B. tabaci, accompanied by the emergence of whitefly‐transmitted geminiviruses. Control measures in infected regions are based mainly on limitation of vector populations, using chemicals or physical barriers. However, under conditions of severe whitefly attack, none of these control measures has sufficed to prevent virus spread. Thus, the best way to reduce geminivirus damage is by breeding crops resistant or tolerant to the virus, either by classical breeding or by genetic engineering. A number of begomoviruses have been the subject of much investigation, due to their severe economic impact. This review considers the most severe viral diseases of four major crops (tomato, bean, cassava and cotton). The approaches taken to breed for resistance to these viral diseases should provide a perspective of the issues involved in breeding for begomovirus resistance in crop plants.     

Detection and relationships of cotton leaf curl virus and allied whitefly-transmitted geminiviruses occurring in Pakistan

A stock culture of cotton leaf curl virus from Pakistan (CLCuV-PK), was transmitted by whiteflies (Bemisia tabaci) to seven plant species, including French bean, okra, tobacco and tomato, and caused vein thickening and leaf curl symptoms. It was readily detected in triple antibody sandwich ELISA (TAS-ELIS A) by 11 out of 31 monoclonal antibodies raised against the particles of three other geminiviruses: African cassava mosaic, Indian cassava mosaic and okra leaf curl viruses. Reaction strength was enhanced when the tissue extraction fluid contained sodium sulphite. Minor variations in epitope profile were found among virus isolates from cotton (Gossypium hirsutum) collected from different districts in Pakistan over a 5-year period. These epitope profiles were distinguishable from that of cotton leaf curl virus from G. barbadense in southern India but indistinguishable from the profiles of viruses causing yellow vein disease of okra in India or Pakistan, or leaf curl of okra {Abelmoschus esculentus), Hibiscus tiliaceus, radish or sunflower in Pakistan, suggesting that these plants are putative natural hosts of CLCuV-PK. The viruses in cotton, and in okra with leaf curl or yellow vein symptoms, were also detected by PCR with three pairs of CLCuV-PK-specific primers. Five additional whitefly-transmitted geminiviruses were found among isolates from 11 other naturally-infected species in Pakistan, and were distinguished by their epitope profiles. These viruses were associated, respectively, with tobacco leaf curl, squash yellow blotch, tomato yellow leaf curl, watermelon leaf crinkle and soybean yellow mosaic diseases. The first four of these viruses were detected readily by PCR with geminivirus general primers but only weakly, if at all, with two pairs of CLCuV-PK-specific primers. Pakistani crops are infected with a range of distinguishable but relatively closely related whitefly-transmitted geminiviruses, some of which resemble those found in India.     

Particle purification, properties and epitope variability of Indian tomato leaf curl geminivirus

A whitefly-transmissible stock isolate of Indian tomato leaf curl geminivirus (ITmLCV) was cultured in graft-inoculated tomato plants and its particles purified from chloroform-clarified extracts in citrate buffer by precipitation with 70 g/litre polyethylene glycol, ultracentrifugation and sucrose density gradient centrifugation. Contaminating helical filaments were eliminated by banding in caesium sulphate gradients. ITmLCV particles had the shape typical for geminiviruses, measured c. 30 × 20 nm and contained a single major protein of estimated mol. wt c. 32 000. They reacted in immunosorbent electron microscopy with antisera to four other whitefly-transmitted geminiviruses. ITmLCV reacted with one out of 17 monoclonal antibodies specific for different epitopes in the particle protein of African cassava mosaic geminivirus and five or six out of 10 monoclonal antibodies to the particle protein of Indian cassava mosaic geminivirus. Virus isolates from tomato at nine locations in Karnataka State showed only slight differences in epitope profile, and isolates from four weed species in tomato fields were similar or identical to those from tomato.     

Comparative epitope profiles of the particle proteins of whitefly-transmitted geminiviruses from nine crop legumes in India

Geminiviruses associated with yellow or golden mosaic diseases of legume crops in two regions of India were compared by testing their reactivity with 27 monoclonal antibodies (MAbs) prepared to the particles of African cassava mosaic (ACMV) or Indian cassava mosaic (ICMV) viruses. The viruses fell into two main groups. Group 1 comprised isolates of dolichos yellow mosaic virus; these reacted with three or four ACMV MAbs and four ICMV MAbs. Group 2 comprised isolates of horsegram yellow mosaic virus, together with isolates from blackgram, cowpea, French bean, pigeonpea, soybean, Indigofera hirsuta and probably also isolates from mungbean. These reacted with three or four ACMV MAbs but with few or no ICMV MAbs. Isolates within each group differed slightly in epitope profile, depending on the source species (Group 2) or geographical origin (Groups 1 and 2). Isolates from lima bean resembled those in Group 2 but had some antigenic differences, and their status is uncertain. The poor detectability of geminivirus isolates in mungbean may reflect a low virus concentration in this species.     

Detection of three whitefly-transmitted geminiviruses occurring in Europe by tests with heterologous monoclonal antibodies

Selected monoclonal antibodies (MAbs), prepared to particles of African cassava mosaic or Indian cassava mosaic geminiviruses, detected three geminiviruses that occur in Europe: abutilon mosaic virus in Abutilon pictum ‘Thompsonii’, tobacco leaf curl virus in Lonicera japonica var. aureo-reticulata and tomato yellow leaf curl virus in Lycopersicon esculentum. All three viruses were detected in indirect ELISA by MAbs SCR 17 and SCR 20 but they were differentiated by their reactions with SCR 18 and SCR 23. Tobacco leaf curl virus was detected only when reducing agents were included in the leaf extraction medium. Inclusion of sodium sulphite slightly improved detection of tomato yellow leaf curl virus but reducing agents were not needed for detection of abutilon mosaic virus.     

Serological detection and antigenic variation of two whitefly-transmitted geminiviruses: tobacco leaf curl and croton yellow vein mosaic viruses

A panel of 25 monoclonal antibodies (MAbs) raised against particles of two heterologous whitefly-transmitted geminiviruses (begomoviruses) was used in triple antibody-sandwich ELISA (TAS-ELISA) to determine the detectability and epitope profiles of 26 Indian isolates of tobacco leaf curl virus (TLCV) and 13 of croton yellow vein mosaic virus (CYVMV). Stock cultures of the two viruses had indistinguishable epitope profiles although they differ in symptomatology and particle stability. Their epitope profiles also strongly resembled those of Indian isolates of bhendi (okra) yellow vein mosaic and Indian cassava mosaic (ICMV) viruses. TLCV isolates from Andhra Pradesh, Gujarat and Karnataka States differed slightly in epitope profile: they reacted with at least eight out of 10 MAbs raised to ICMV but only one to four out of 15 MAbs raised to African cassava mosaic virus (ACMV). Virus isolates serologically indistinguishable from TLCV were detected in symptom-bearing weeds (Acanthospermum hispidum, Ageratum conyzoides, Euphorbia geniculata, Parthenium hysterophorus) found in leaf curl-affected tobacco fields and shown previously to be experimental hosts of TLCV. Indian TLCV isolates had small, consistent differences in epitope profile from Pakistani isolates but large differences from isolates from Burkina Faso, Malawi or Uganda. Isolates from the three African countries reacted with four or five of the ACMV MAbs but only one or two of the ICMV MAbs, and there were small but consistent inter-country differences. CYVMV isolates from three Indian States showed less epitope variation than did Indian isolates of TLCV. TAS-ELISA with MAb SCR 18 was a more sensitive test for detecting Indian TLCV isolates than was double antibody-sandwich ELISA with polyclonal antibodies.     

Biological properties,transmission, serological characterization and varietal susceptibility of an isolate of Papaya leaf curl virus affecting papaya crops in Eastern Uttar Pradesh,India

Papaya leaf curl disease (PLCD) was recorded with 5–35% incidence at six districts of Eastern Uttar Pradesh during survey. The characteristic symptoms observed were severe downward leaf curling, swelling of veins, twisting and reduction of petioles, inverted leaf bowls and stunted growth of the entire plant which bore only few small and distorted fruit. The virus isolate was identified as Papaya leaf curl virus (PaLCuV).The PaLCuV isolate was successfully transmitted by whitefly (Bemisia tabaci) but not by mechanical (sap) transmission on Carica papaya plants. Plants could be proved efficiently from infected to healthy C. papaya, Capsicum annuum, Lycopersicon esculentum, Nicotiana tabacum, Crotalaria juncea, Ageratum conyzoides, Zinnia elegans, Datura stramonium and Petunia hybrida. Symptomatic samples of these plants were tested with polyclonal antiserum of Tomato leaf curl New Delhi virus by DAC-ELISA test showed the positive relationship of the samples with geminivirus. On the basis of symptomatology, whitefly transmission, host range studies and serological relationship, the isolate was identified as whitefly transmitted geminivirus. To identify potential varietal resistances source to PaLCuV, five cultivars of C. papaya were tested against PaLCuV using whitefly insects to transmit the infection. Results revealed that two cultivars (Washington and Ranchi Dwarf) were found to be moderately resistant.     

The contribution of tomato and alternative host plants to tomato leaf curl virus inoculum pressure in different areas of South India

Indian tomato leaf curl virus (ToLCV) (Geminiviridae: Sub-group III) was detected both in field-collected and laboratory-reared B. tabaci using a triple-antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA). ToLCV was detected in six of the 10 group samples of field collected B. tabaci. ToLCV was also identified in 13 weed species commonly found in Karnataka, both by symptom expression and TAS-ELISA. ToLCV from c. 61% of infected plants was transmitted successfully to tomato by B. tabaci. Tomato plots were planted at three locations on the University of Agricultural Sciences Campus, Bangalore. Indian tomato leaf curl virus disease (ToLCVD) incidence increased most rapidly when the tomato plot was situated adjacent to an older ToLCVD-infected tomato field. When the plots were positioned in a dryland or a wetland area, at least 500 m away from any infected tomato fields, the ToLCVD incidence increased less rapidly, although in all sites it was 100% by 11 wk after transplanting. The numbers of B. tabaci caught on yellow traps in all sites increased during weeks 1–3 after transplanting and thereafter remained at between 10–15 adults trap^-1 24 h^_1. Adult numbers recorded on tomato plants by direct counts remained approximately constant at 2–4 adults plant“”¹. Tomato fields were planted in three taluks (administrative areas) of Karnataka, that had different current and previous histories of tomato production. ToLCVD incidence increased most and least rapidly, respectively, in Kolar taluk where tomato is grown continuously and Doddaballapur tuluk where tomato was grown in the area for the first time. In Malur tuluk, where tomato was grown discontinuously (once a year), the incidence of ToLCVD increased at an intermediate rate. Weed host-plant species growing near the experimental sites had averages of between 1.5–10.0 B. tabaci nymphs per plant, whereas the tomato plants had only 0.3 nymphs per plant. The percentage parasitism of B. tabaci nymphs on tomato and weed species, respectively, was 0.7% and 2–6%. Nymphs and pupae were parasitised by an Encarsia sp. and Eretmocerus mundus Mercet. The relevance and implications of these findings for the epidemiology and management of ToLCVD in Karnataka State, South India is discussed.     

Host range, vector relations and serological relationships of cotton leaf curl virus from southern India

In 1989 to 1991, leaf curl disease was observed in cotton (Gossypium bar-badense cv. Local) grown in kitchen gardens in five districts in Karnataka State, India, and in 1994 it was recorded in G. hirsutum cv. Sharada in two districts. Symptoms consist of leaf curling, vein thickening, leaf enations, and stunting and distortion of plants. The disease is caused by cotton leaf curl virus (CLCuV-K), which was transmitted by the whitefly Bemisia tabaci to 24 plant species in six families. Hosts include bean (Phaseolus vulgaris), pepper, tobacco, tomato and several weeds, almost all of which developed leaf curl, with or without vein thickening. CLCuV-K was transmitted from cotton to cotton by adult B. tabaci after an acquisition access period of 1 h, could be inoculated in 5 min, had a minimum latent period of 8 h and was retained by viruliferous insects for up to 9 days. Female B. tabaci transmitted more frequently than males. CLCuV-K is a whitefly-transmitted geminivirus. It reacted with two out of 17 monoclonal antibodies (MAbs) raised to African cassava mosaic virus and five out of 10 MAbs raised to Indian cassava mosaic virus. CLCuV-K isolates from different locations in Karnataka had similar epitope profiles. As judged by these profiles, CLCuV-K is closely related to Indian tomato leaf curl virus from Karnataka, is distinguishable from several other whitefly-transmitted geminiviruses found in India and is still more distantly related to those, including cotton leaf crumple virus from the USA, found in other continents. CLCuV-K infected all cultivars tested of G. barbadense and one of six cultivars of G. hirsutum but none of G. arboreum or G. herbaceum.     

Detection and differentiation of whitefly-transmitted geminiviruses in plants and vector insects by the polymerase chain reaction with degenerate primers

Degenerate oligonucleotide primers, designed for amplification of an approx. 500 bp fragment of DNA-A of five well characterised whitefly-transmitted geminiviruses, were used in the polymerase chain reaction (PCR) to detect known or putative geminiviruses infecting seven plant species and originally obtained from Africa, India, America or Europe. Although nucleotide sequences are published for only four of the viruses, all 13 were detected. Six of the viruses were also detected in single viruliferous whiteflies (Bemisia tabaci). Virus was detected both in fresh B. tabaci and in specimens that were frozen and dried before being dispatched from their country of origin. Individual viruses could be distinguished by the patterns of DNA fragments obtained by the action of restriction endonucleases on the PCR products. This approach also allowed six virus isolates from leaf curl-affected tomato to be assigned to four country-specific forms.     

Transmission of tomato leaf curl geminiviruses by Bemisia tabaci: effects of virus isolate and vector biotype

Cultures of Bemisia tabaci from Ivory Coast (IC), Pakistan (PK) and USA (US B-type) were compared for the frequency with which they transmitted three tomato geminivirus isolates: Indian tomato leaf curl virus from Bangalore (ITmLCV), and tomato yellow leaf curl viruses from Nigeria (TYLCV-Nig) and Senegal (TYLCV-Sen). Frequency of transmission from tomato to tomato depended both on the whitefly culture and the virus isolate. US B-type and IC whiteflies transmitted TYLCV-Sen more frequently than ITmLCV whereas PK whiteflies transmitted ITmLCV more frequently than TYLCV-Sen. US B-type whiteflies transmitted both viruses four to nine times more frequently than IC whiteflies. TYLCV-Nig was transmitted rarely by US B-type and not at all by IC whiteflies. Previous work indicates that the geminivirus coat protein controls vector transmissibility. The differential adaptation of TYLCV-Sen to transmission by US B-type whiteflies and of ITmLCV to PK whiteflies was associated with a large difference in epitope profile of the coat proteins of the two viruses. Also, the readily transmissible TYLCV-Sen differed appreciably in epitope profile from the poorly transmissible TYLCV-Nig, which reached a consistently greater concentration in source tissues but lacked epitope 18. However, the lack of epitope 18 in ITmLCV did not prevent its transmission by US B-type whiteflies. Differences in frequency and specificity of geminivirus transmission by whitefly cultures from different countries therefore were associated with differences among epitope profiles of the coat proteins of the viruses, but the structural features of the proteins that control transmission remain to be determined.     

不同邻作作物对番茄田间烟粉虱种群动态的影响

为明确不同邻作模式下番茄田间烟粉虱的种群动态与空间分布格局,于云南省昆明市选取与西葫芦、黄瓜、玫瑰等作物邻作的番茄田及单作番茄田为研究样地,通过五点取样法进行调查,采用四分位法对不同作物邻作的番茄田间烟粉虱种群动态进行分析.结果表明:在烟粉虱的主要发生期,番茄单作田间烟粉虱种群数量最高,雌成虫达26.69头?叶-1,雄...     

Epidemiology of tobacco leaf curl virus in India

The incidence of disease caused by tobacco leaf curl geminivirus (TbLCV) in ten tobacco growing areas of India ranged from 1.2% to 77%. The highest incidence of disease was observed in Andhra Pradesh (77%) followed by Gujarat (59%), Karnataka (17%), Bihar (11.6%) and West Bengal (5.4%). Under field conditions, an average of 32 adult whiteflies (Bemisia tabaci) per plant were recorded in Andhra Pradesh followed by Gujarat (20), Karnataka (12), Bihar (8) and West Bengal (5). In sequential sowings at Bangalore, all the plants were infected within 90 days in plots planted from February to June. Infection in plots planted later was progressively less. There was a positive correlation between whitefly catches and the final incidence of leaf curl disease in plantings. TbLCV was transmitted by Bemisia tabaci to 35 plant species, including Beta vulgaris, Capsicum annuum, Carica papaya, Cymopsis tetragonoloba, Lycopersicon esculentum, Sesamum indicum, Phaseolus vulgaris and Petunia hybrida. Forty five TbLCV isolates from different parts of India induced four distinct types of symptoms on tobacco cultivars Samsun and Anand 119. Group 1 isolates caused severe curling and cup-shaped enations; group II isolates induced pale green leaves, pit-like depressions and thorny enations: group III isolates caused leathery leaves, narrow and tiny protruding enations between the veins, and group IV isolates induced irregular thickening and swelling of veins and green flap-like enations on veins. Nylon net covers protected tobacco seedlings in nursery beds for 45 days. Ricinus communis and Helianthus annuus sown around the tobacco nursery bed as barrier crops attracted adult whiteflies and decreased the number found on tobacco.     

Discrimination of cassava-associated Bemisia tabaci in Africa from polyphagous populations, by PCR–RFLP of the internal transcribed spacer regions of ribosomal DNA

Restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA internal transcribed spacer regions of Bemisia tabaci was used to distinguish cassava‐associated populations from other host‐associated populations. Endonuclease restriction profile analysis indicated that cassava‐associated populations from Africa represent a distinct group, with a significant level of separation into subgroups that were not linked to geographical origin. Analysis of molecular variance (amova ) revealed that a high proportion of the total genetic variation (47%) was attributable to among‐population differences within the host‐associated groups. Principal coordinate analysis supported the differentiation between the cassava and the non‐cassava group, a result which was in agreement with the cluster analysis of the restriction fragment profile. Internal transcribed spacer RFLP markers, especially SmaI, identified in this study can be used to monitor the spread of B. tabaci biotypes, especially of the more virulent biotype B that has so far not been reported in the cassava‐growing belt of Africa.     

烟粉虱在烟株上的垂直分布及寄主选择性

烟粉虱是云南省农业生产上的重要害虫之一。通过田间系统调查和室内观察相结合,研究了烟粉虱在烟株上的垂直分布特性和在8种寄主作物上的取食、产卵趋性。（1）烟粉虱在烟株上的垂直分布特征为上部＞中部＞下部,8月中旬为种群高峰期,上、中、下部叶片的成虫密度分别为15．1、10．9、6．7头？片-1;（2）烟粉虱成虫的取食趋性表现为大豆＞南瓜＞甘薯＞番茄＞一品红＞茄子＞甘蓝＞烟草,各处理间差异不显著（P＞0．05）;（3）产卵趋性表现为一品红＞大豆＞南瓜＞甘薯＞番茄＞茄子＞甘蓝＞烟草,一品红与南瓜、甘蓝、茄子、甘薯、番茄、烟草处理间,以及大豆与烟草处理间存在显著差异（P＜0．05）,其他处理间差异不显著（P＞0．05）。在所测定的8种寄主植物中,烟粉虱成虫对烟草的选择性最差,烟区规划烟田种植范围时,应避免与大豆、南瓜、甘薯、番茄等作物间作或距离太近。     

江苏金坛地区烟粉虱的发生扩散及寄主适合性分析

系统调查表明,金坛市尧塘花木基地是该地区烟粉虱扩散蔓延的虫源地。该虫4月下旬逐渐从越冬虫源地向外扩散蔓延,首先在葎草[Humulus scandens(Lour)M err]上产卵危害,然后再危害其它植物;距虫源地越近,发生的时间早,虫口密度高,反之,则发生的时间迟,虫口密度低;11月下旬部分种群迁移到温室大棚内越冬。本文还提出了相应的控制措施。     

Effect of geminivirus infection and Bemisia infestation on accumulation of pathogenesis-related proteins in tomato

The whitefly, Bemisia tabaci biotype B, has been shown to cause pathogenesis-related (PR) proteins to accumulate in plants as a result of direct feeding, but their specific role in plant defensive systems is unclear. Our objective was to compare accumulation of tomato PR proteins (beta-1,3-glucanase, chitinase, peroxidase, P2 and P4) in response to whitefly, with or without tomato mottle virus (ToMoV) infection. Tomato PR protein response was measured over time in plants divided into three treatments: uninfected controls (with or without whiteflies) and plants infested with viruliferous (ToMoV) whiteflies. Five- to six-leaf plants were infested with approximately 5 adult whitefly per leaf. Plants were sampled prior to whitefly infestation and at 14, 28, 42, and 56 days. By 56 days, plants infested with viruliferous whiteflies had significantly more eggs (2.5-fold) and nymphs (4.5-fold) than plants with nonviruliferous whiteflies. A significant increase in the enzymatic activity of all measured PR proteins, as compared to control plants, was only seen in viruliferous whitefly-infested plants. No significant difference was observed in enzyme activities between the uninfected control plants either with or without whiteflies. The greatest differences for all PR proteins assayed were observed 42 days after treatment initiation. Protein blot analyses showed that the differences in PR protein activities among the treatments were due to changes in specific enzyme levels within the plant and were associated with concomitant increases in levels of P2 and P4 PR proteins. Under our experimental conditions, it is clear that PR protein response is much more intense when it is attacked by whiteflies carrying ToMoV than by whitefly alone.     

辽宁省冬季温室内越冬粉虱伪蛹的种类鉴定及烟粉虱体内番茄黄化曲叶病毒的检测

为了揭示辽宁省冬季温室内越冬粉虱伪蛹的种类及烟粉虱Bemisia tabaci （Gennadius）携带番茄黄化曲叶病毒（tomato yellow leaf curl virus, TYLCV）情况, 于2012年1月份在辽宁省不同县市区的温室作物上采集了17份粉虱伪蛹样品（每样品含30头粉虱伪蛹） , 镜检鉴别粉虱种类并利用mtCOI基因对烟粉虱生物型进行了鉴定; 检测了烟粉虱携带TYLCV情况并对其PCR扩增产物进行了测序分析。结 果表明： 辽宁省冬季温室内存在越冬温室白粉虱Trialeurodes vaporariorum （Westwood）与烟粉虱。17份粉虱样品中, 11份样品为烟 粉虱样品, 6份样品为温室白粉虱和烟粉虱混合样品。混合样品中, 温室白粉虱仅在锦州凌海（LH）样品中占优势。17份烟粉虱样品（包 括混合样品）中, 仅有4份样品为B型与Q型混合样品, 其他13份样品烟粉虱生物型均为Q型。17份烟粉虱样品中有3份Q型烟粉虱样品检测 到TYLCV, 系统树分析进一步证实该病毒是TYLCV。调查结果为辽宁省粉虱与TYLCV的早期测报和防控提供了科学依据。     

Genome-wide identification of neuropeptides and their receptor genes in Bemisia tabaci and their transcript accumulation change in response to temperature stresses

Insect neuropeptides play an important role in regulating physiological functions such as growth,development,behavior and reproduction.We identified temperaturesensitive neuropeptides and receptor genes of the cotton whitefly,Bemisia tabaci.We identified 38 neuropeptide precursor genes and 35 neuropeptide receptors and constructed a phylogenetic tree using additional data from other insects.As temperature adaptability enables B.tabaci to colonize a diversity of habitats,we performed quantitative polymerase chain reaction with two temperature stresses(low=4℃ and high=40℃)to screen for temperature-sensitive neuropeptides.We found many neuropeptides and receptors that may be involved in the temperature adaptability of B.tabaci.This study is the first to identify B.tabaci neuropeptides and their receptors,and it will help to reveal the roles of neuropeptides in temperature adaptation of B.tabaci.