Horizontal transmission of begomoviruses between Bemisia tabaci biotypes

We have previously shown that the monopartite Tomato yellow leaf curl virus (TYLCV), a begomovirus (family Geminiviridae, genus Begomovirus) infecting tomato plants can be transmitted in a gender-dependent manner among its insect vector the whitefly Bemisia tabaci type B (Gennaduis) (Aleyrodidae: Hemiptera) during mating. Viruliferous females were able to transmit the virus to non-viruliferous males and vice versa, in the absence of any other virus source. The recipient insects were able to infect tomato plants. In this communication, we present evidence that two bipartite begomoviruses infecting cucurbits, Squash leaf curl virus (SLCV) and Watermelon chlorotic stunt virus (WmCSV) can be transmitted in a gender-dependent manner among whiteflies. In addition we show that TYLCV can be transmitted during mating among individuals from the same biotype (from B-males to B-females and vice versa; and from Q-males to Q-females and vice versa). However, viruliferous males of the B biotype are unable to transmit the virus to females of the Q biotype (and vice versa); similarly, viruliferous males of the Q biotype are unable to transmit the virus to females of the B biotype (and vice versa). These findings support the hypothesis that a pre-zygotic mating barrier between the Q and B biotypes is the cause for the absence of gene flow between the two biotypes, and that virus transmission can be used as a marker for inter-biotype mating. To be transmitted during mating, the virus needs to be present in the haemolymph of the donor insect. Abutilon mosaic virus (AbMV), a bipartite begomovirus that can be ingested but not transmitted by B. tabaci, is absent in the whitefly haemolymph, and cannot be transmitted during mating. Mating was a precondition for horizontal virus transfer from male to female, or female to male. Virus was not transmitted when viruliferous B. tabaci were caged with the non-vector non-viruliferous whitefly Trialeurodes vaporariorum (Westwood) (Aleyrodidae: Hemiptera) and vice versa.     

湖北省烟粉虱生物型鉴定

本研究利用mtDNA COI基因片段作标记,通过序列分析对湖北省烟粉虱Bemisa tabaci(Gennadius)生物型进行了鉴定。结果表明当阳、仙桃、天门、监利、宜昌和武汉6个地理种群烟粉虱的720bp COI基因序列的同源性高达100%,且该6个地理种群烟粉虱与USA-Q型烟粉虱、湖北Q型烟粉虱的同源性也高达100%。枣阳地区烟粉虱与Israel-B型烟粉虱、我国浙江B型烟粉虱、我国湖北B型烟粉虱的同源性为100%。由此可见当阳、仙桃、天门、监利、宜昌和武汉6个地区烟粉虱生物型属于Q型,仅枣阳地区烟粉虱属于B型。     

不同生物型烟粉虱体内Wolbachia共生菌的检测及其系统树分析

Wolbachia是广泛分布于节肢动物体内一类共生细菌,它能够通过多种机制调控宿主的生殖方式。近年来的研究表明,Wolbachia与许多外来生物的成功入侵相关。本文利用长PCR的方法特异扩增了不同生物型烟粉虱（共24个种群）体内Wolbachia的wsp基因,结果发现B型和Q型烟粉虱入侵种群体内均未检测到Wolbachia,而在非B/Q型的浙江种群和肯尼亚种群体内检测到了Wolbachia。对该wsp基因进行测序并和已知序列进行同源性分析发现,浙江烟粉虱种群的Wolbachia属于B组Con/Rug亚种群,而肯尼亚种群属于B组Btab1亚种群。Wolbachia的存在与否可能与烟粉虱的成功入侵有一定的关系。图2表2参23     

Distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) biotypes in North America after the Q invasion

After the 2004 discovery of the Bemisia tabaci (Gennadius) (Hemiptera Aleyrodidae) Q biotype in the United States, there was a vital need to determine the geographical and host distribution as well as its interaction with the resident B biotype because of its innate ability to rapidly develop high-level insecticide resistance that persists in the absence of exposure. As part of a coordinated country-wide effort, an extensive survey of B. tabaci biotypes was conducted in North America, with the cooperation of growers, industry, local, state, and federal agencies, to monitor the introduction and distribution of the Q biotype. The biotype status of submitted B. tabaci samples was determined either by polymerase chain reaction amplification and sequencing of a mitochondrial cytochrome oxidase I small subunit gene fragment and characterization of two biotype discriminating nuclear microsatellite markers or esterase zymogram analysis. Two hundred and eighty collections were sampled from the United States, Bermuda, Canada, and Mexico during January 2005 through December 2011. Host plants were split between ornamental plant and culinary herb (67%) and vegetable and field crop (33%) commodities. The New World biotype was detected on field-grown tomatoes (Solanum lycopersicum L.) in Mexico (two) and in commercial greenhouses in Texas (three) and represented 100% of these five collections. To our knowledge, the latter identification represents the first report of the New World biotype in the United States since its rapid displacement in the late 1980s after the introduction of biotype B. Seventy-one percent of all collections contained at least one biotype B individual, and 53% of all collections contained only biotype B whiteflies. Biotype Q was detected in 23 states in the United States, Canada (British Columbia and Ontario territories), Bermuda, and Mexico. Forty-five percent of all collections were found to contain biotype Q in samples from ornamentals, herbs and a single collection from tomato transplants located in protected commercial horticultural greenhouses, but there were no Q detections in outdoor agriculture (vegetable or field crops). Ten of the 15 collections (67%) from Canada and a single collection from Bermuda contained biotype Q, representing the first reports of biotype Q for both countries. Three distinct mitochondrial haplotypes of B. tabaci biotype Q whiteflies were detected in North America Our data are consistent with the inference of independent invasions from at least three different locations. Of the 4,641 individuals analyzed from 517 collections that include data from our previous work, only 16 individuals contained genetic or zymogram evidence of possible hybridization of the Q and B biotypes, and there was no evidence that rare hybrid B-Q marker co-occurrences persisted in any populations.     

江苏地区烟粉虱发生危害及其生物型监测

【目的】随着Q型和B型烟粉虱Bemisia tabaci(Gennadius)在全世界范围内的传播和入侵,两种入侵烟粉虱的发生危害和种群扩张越来越受到人们的关注。本文对2010—2013年江苏省内烟粉虱的发生危害程度及其生物型的分布进行了全面的调查研究。【方法】应用室内镜检鉴定烟粉虱的发生危害程度,同时结合mt COⅠ分子标记快速检测法鉴定烟粉虱的生物型。【结果】从时间来看,烟粉虱的发生危害程度在2011年最严重,而在2013年最低,呈"先上升后下降"的趋势。从不同地区来看,苏南和苏北地区呈现出"先上升后下降"的趋势,而苏中地区与之相反。从寄主来看,烟粉虱在茄子,黄瓜和南瓜上的发生危害程度最严重。【结论】烟粉虱在江苏省内的发生危害程度因时间,地区和寄主的不同而差异显著,这种差异与烟粉虱不同生物型之间的竞争取代没有直接联系。虽然Q型烟粉虱在江苏省内占据了优势地位,但是B型烟粉虱在苏南和苏北地区仍然占据了一定的比例,并且有逐步上升的趋势。     

江苏地区烟粉虱生物型演替研究初报

本文连续5年系统监测了江苏省13个地级市烟粉虱Bemisia tabaci(Gennadius)生物型的发生分布状况,探讨了它们的迁移扩散和演替规律。利用RAPD分子标记和mtDNA COI基因序列进行烟粉虱生物型鉴定,结果表明:江苏地区发生的烟粉虱生物型为B型和Q型。自2005年到2009年,B型烟粉虱在苏南和苏北地区的发生分布频率逐年下降,在苏北地区的发生分布频率由52.58%下降为22.22%,在苏南由56.52%下降为9.37%;而Q型烟粉虱在苏南和苏北的发生分布频率逐年升高,在苏北由47.42%上升至77.78%,在苏南由43.48%上升为90.63%。B型烟粉虱的发生分布范围由全省逐渐向苏北地区缩小,而Q型烟粉虱的发生分布范围逐渐扩大遍及全省;此外,Q型烟粉虱在江苏是由苏中和苏南地区向苏北地区扩散,并逐步取代B型烟粉虱成为江苏地区农作物的主要害虫。     

Distribution patterns of the Q and B biotypes of Bemisia tabaci in the Mediterranean Basin based on microsatellite variation

At least five of the biotypes described in the Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) complex are known to be present in the Mediterranean Basin area. Only two of them, however, are economically relevant, that is, biotypes B and Q. Biological and genetic differences between the two biotypes have been well studied, but less is known about their patterns of genetic variation and population structure. To address these issues, a study was undertaken based on variation at six microsatellite loci among a subset of nine B. tabaci populations (five belonging to the Q and four to the B biotype). The data obtained show that (i) these loci showed considerable polymorphism in the Q and B biotypes populations although the presence of null alleles can obscure the picture; (ii) the Iberian‐Q, Canarian‐Q, and Egyptian‐B populations exhibit heterozygosity excess as a result of bottleneck events; (iii) the low genetic differentiation between the Israeli, Iberian Peninsula, and Italian populations suggest that these populations share a common gene pool; (iv) the genetic distances between the Canarian‐Q population and the geographically close population from Morocco indicates spatial isolation and a limited gene flow; and finally (v) the microsatellite data for the B populations indicate that the whiteflies from Egypt and Israel have a close phylogenetic relationship, but the source of these biotype B invasions into the Mediterranean area remains unknown.     

Symbiont diversity and non-random hybridization among indigenous (Ms) and invasive (B) biotypes of Bemisia tabaci

The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is a worldwide pest and a vector of numerous plant viruses. B. tabaci is composed of dozens of morphologically indistinguishable biotypes and its taxonomic status is still controversial. This phloem-feeder harbours the primary symbiont Portiera aleyrodidarum and potentially six secondary symbionts: Cardinium, Arsenophonus, Hamiltonella, Rickettsia, Wolbachia and Fritschea. In the southwest Indian Ocean, La Réunion hosts two biotypes of this species: B (invasive) and Ms (indigenous). A multiplex PCR was developed to study the symbiont community of B. tabaci on La Réunion. Symbiont community prevalence and composition, host mitochondrial and nuclear genetic diversity, as well as host plant and localization, were described on field populations of La Réunion for B and Ms B. tabaci biotypes and their hybrids. A clear association between symbiotypes and biotypes was shown. Cardinium, Arsenophonus and Rickettsia were found in the Ms biotype (73.6%, 64.2% and 3.3%, respectively). Hamiltonella (exclusively) and Rickettsia were found in the B biotype (78% and 91.2%, respectively). Hybrids harboured all symbiotypes found in Ms and B populations, but with a higher prevalence of Ms symbiotypes than expected under random hybridization. An unexpected majority was Cardinium mono-infected (65.6%), and a striking minority (9%) harboured Cardinium/Arsenophonus. In the hybrids only, genetic diversity was linked to symbiotype. Among the hybrids, significant links were found between symbiotypes and: (i) mitochondrial COI sequences, i.e. maternal origin; and (ii) alleles of nuclear microsatellite loci, specific to either Ms or B parental biotype. Taken together, our results suggest that Cardinium and/or Arsenophonus may manipulate the reproduction of indigenous (Ms) with invasive (B) biotypes of Bemisia tabaci.     

Host suitability of two biotypes of Bemisia tabaci on some common weeds

Significant differences in some reproductive parameters of the B and Q biotypes of Bemisia tabaci (Gennadius) with regard to four species of winter weeds were determined in a no-choice assay. The highest fecundity (eggs) and fertility (pupae and adults) were obtained with Malva parviflora L. as host, followed by Capsella bursa-pastoris L., Brassica kaber (DC) and Lactuca serriola L. The percentage of adult emergence (from egg to adult) was significantly higher (P < 0.001) with M. parviflora, C. bursa-pastoris and B. kaber than with L. serriola. Except on L. serriola, the mean values of the reproductive parameters for the Q-biotype were significantly (P < 0.05) greater than those for the B-biotype. On the other hand, in choice experiments with summer weeds, both B- and Q-biotypes preferred Datura stramonium L. and Solanum nigrum L. to Amaranthus retroflexus L., Chenopodium album L. and Echinochloa crus-galli L. Significantly more males and females, and more pupae and empty pupal cases per plant were found on D. stramonium than on S. nigrum. Adult abundance on A. retroflexus, C. album and E. crus-galli plants was very low. At a constant temperature of 26 ± 1°C, the Q-biotype developed significantly faster than the B-biotype on S. nigrum and D. stramonium. Both biotypes required, for this development, significantly more days on D. stramonium than on S. nigrum. These results suggest that it is important to suppress the growth of M. parviflora, C. bursa-pastoris, B. kaber, D. stramonium and S. nigrum in order to avoid the risk of further expansion of whitefly populations where these weeds and both B- an Q-biotypes are present.     

A Bemisia tabaci midgut protein interacts with begomoviruses and plays a role in virus transmission

Begomoviruses are a major group of plant viruses, transmitted exclusively by Bemisia tabaci (Gennadius) in a persistent circulative non‐propagative manner. The information regarding molecular and cellular basis underlying Begomovirus – whitefly interaction is very scarce. Evidences have suggested that the insect gut possesses some crucial protein receptors that allow specific entry of virus into the insect haemolymph. We have performed yeast two hybrid gut cDNA expression library screening against coat protein of Tomato leaf curl New Delhi virus (ToLCV) and Cotton leaf curl Rajasthan virus (CLCuV) as bait. Midgut protein (MGP) was the common protein found interacting with both ToLCV and CLCuV. MGP was localized in whole mount B. tabaci as well as in dissected guts through confocal microscopy. Pull down and dot blot assays confirmed in vitro interaction between ToLCV/CLCuV coat protein and MGP. Immunolocalization analysis also showed colocalization of ToLCV/CLCuV particles and MGP within insect's gut. Finally, anti‐MGP antibody fed B. tabaci, exhibited 70% reduction in ToLCV transmission, suggesting a supportive role for MGP in virus transmission.     

Distribution and molecular characterization of distinct Asian populations of Bemisia tabaci (Hemiptera: Aleyrodidae) in Japan

Bemisia tabaci (Gennadius) is considered to be the most economically important pest insect worldwide. The invasive variant, the Q biotype of B. tabaci was first identified in 2004, and has caused significant crop yield losses in Japan. The distribution and molecular characterization of the different biotypes of B. tabaci in Japan have been little investigated. In this study, B. tabaci populations were sampled from the Japanese Archipelago, the Amami Archipelago and the Ryukyu Islands between 2004 and 2008, and the nucleotide sequences of their mitochondrial cytochrome oxidase I genes were determined. Bayesian phylogenetic relationship analysis provided the first molecular evidence that the indigenous Japanese populations could be separated into four distinct genetic groups. One major native population from the Japanese Archipelago, given the genetic group name Lonicera japonica, was separated into an independent group, distinct from the other genetic groups. The second major population, the Nauru biotype in the Asia II genetic group, was identified in the Amami Archipelago and the Ryukyu Islands. Two distinct minor genetic groups, the Asia I and the China, were also identified. One invasive B‐related population belonging to the Mediterranean/Asia Minor/Africa genetic group has been identified in Honshu. All lineages generated by the phylogenetic analyses were supported by high posterior probabilities. These distinct indigenous B. tabaci populations developed in Japan under geographical and/or biological isolation, prior to recent invasions of the B and Q biotypes.     

Ingestion, transmission, and persistence of Chino del tomate virus (CdTV), a New World begomovirus, by Old and New World biotypes of the whitefly vector Bemisia tabaci

Two whitefly biotypes of Bemisia tabaci, from either the Eastern or Western Hemisphere, respectively, were compared with respect to their competency to ingest and their efficiency to transmit the New World begomovirus, Chino del tomate virus (CdTV). The AZ A biotype of B.tabaci originates from the arid southwestern USA and northwestern Mexico, while the B biotype has an origin in the Middle East or Northern Africa. The ability of these two vector biotypes to ingest and subsequently to transmit CdTV were evaluated for an acquisition‐access period (AAP) that ranged from 0 to 72 h, followed by a 48 h inoculation‐access period (IAP). Individual adult whiteflies were monitored for CdTV ingestion using polymerase chain reaction (PCR) to detect the viral coat protein gene (AV1 ORF), and transmission efficiency (frequency) was determined by allowing potentially viruliferous whiteflies access to tomato seedlings following each experimental AAP. PCR results for individual adult whiteflies indicated that CdTV was ingested from infected tomato plants by both biotypes 93% of the time. Transmission frequencies by both vector biotypes increased with longer AAPs. However, the AZ A biotype transmitted CdTV 50% of the time, compared to only 27% for the B biotype. Evidence that virus was ingested with equal competency by the A and B biotypes confirmed that both vectors were capable of ingesting CdTV from tomato at the same frequency, even when the AAP was 0.5 h. Consequently, either the acquisition and/or transmission stages of the pathway, rather than ingestion competency, were responsible for differences in vector‐mediated transmissibility. Detection frequency of CdTV, after 48 h AAP, by PCR in single females of AZ B biotype was significantly higher than males.     

Genetic diversity and geographic distribution of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) genotypes associated with cassava in East Africa

The genetic variability of whitefly (Bemisia tabaci) species, the vectors of cassava mosaic begomoviruses (CMBs) in cassava growing areas of Kenya, Tanzania, and Uganda, was investigated through comparison of partial sequences of the mitochondria cytochrome oxidase I (mtCOI) DNA in 2010/11. Two distinct species were obtained including sub‐Saharan Africa 1 (SSA1), comprising of two sub‐clades (I and II), and a South West Indian Ocean Islands (SWIO) species. Among the SSA1, sub‐clade I sequences shared a similarity of 97.8–99.7% with the published Uganda 1 genotypes, and diverged by 0.3–2.2%. A pairwise comparison of SSA1 sub‐clade II sequences revealed a similarity of 97.2–99.5% with reference southern Africa genotypes, and diverged by 0.5–2.8%. The SSA1 sub‐clade I whiteflies were widely distributed in East Africa (EA). In comparison, the SSA1 sub‐clade II whiteflies were detected for the first time in the EA region, and occurred predominantly in the coast regions of Kenya, southern and coast Tanzania. They occurred in low abundance in the Lake Victoria Basin of Tanzania and were widespread in all four regions in Uganda. The SWIO species had a sequence similarity of 97.2–97.7% with the published Reunion sequence and diverged by 2.3–2.8%. The SWIO whiteflies occurred in coast Kenya only. The sub‐Saharan Africa 2 whitefly species (Ug2) that was associated with the severe CMD pandemic in Uganda was not detected in our study.     

Colonization of non-cassava plant species by cassava whiteflies (Bemisia tabaci) in Uganda

Bemisia tabaci (Genn.) (Homoptera: Aleyrodidae) is the vector of cassava mosaic geminiviruses (CMGs), which are the main production constraint to cassava [Manihot esculenta Crantz (Euphorbiaceae)], both in Uganda and elsewhere in Africa. Two B. tabaci genotype clusters, Ug1 and Ug2, differentiated at 8% nucleotide (nt) divergence within the mitochondrial cytochrome oxidase I (mtCOI) gene, have been shown to occur on cassava in Uganda. However, the role of alternative hosts in the ecology of cassava B. tabaci genotypes and their possible involvement in the epidemiology of cassava mosaic disease (CMD) in Uganda remain unknown. In this study, we investigated the restriction of cassava B. tabaci genotypes to cassava and the colonization of alternative host species in select cassava‐growing areas of the country in 2003 and 2004. Bemisia tabaci adults and 4th instar nymphs were collected from cassava and 11 other cultivated and uncultivated species occurring adjacent to the sampled cassava fields. Phylogenetic analysis of mtCOI sequences revealed that only a single genotype cluster, Ug1, was present on both cassava and non‐cassava plant species sampled in this study. The Ug1 genotypes (n = 49) shared 97–99% nt identity with the previously described cassava‐associated B. tabaci populations in southern Africa, and were ～8% and ～13% divergent from Ug2 and the ‘Ivory Coast cassava’ genotypes in Uganda and Ivory Coast, respectively. The Ug1 genotypes occurred (as adults) on all 12 source‐plant species sampled. However, based on the presence of B. tabaci 4th instar nymphs, the Ug1 genotypes (n = 13) colonized cassava and five other non‐cassava plant species: Manihot glaziovii, Jatropha gossypifolia, Euphorbia heterophylla, Aspilia africana, and Abelmoschus esculentus, suggesting that cassava B. tabaci (Ug1 genotypes) are not restricted to cassava in Uganda. No Ug2‐like genotypes were detected on any of the plant species sampled, including cassava, in this study. The identification of additional hosts for at least one genotype cluster, Ug1, known also to colonize cassava, and which was hitherto thought to be ‘cassava‐restricted’ may have important epidemiological significance for the spread of CMGs in Uganda.     

Genetic diversity of Bemisia tabaci cryptic species in Nigeria and their relationships with endosymbionts and acquired begomoviruses

Bemisia tabaci is a species complex of at least 44 cryptic species with a worldwide distribution. It is a serious pest of many crop plants as well as a successful vector of at least 100 begomoviruses. Using B. tabaci collected from cassava and tomato fields in the southwestern and north central regions of Nigeria, we determined nucleotide sequences from the mitochondrial cytochrome c oxidase subunit I (COI) of 23 B. tabaci samples, the 16S and 23S ribosomal DNA of endosymbionts, and the coat protein gene of geminiviruses ingested by the whiteflies. The COI analysis identified three different genetic groups including the indigenous Sub-Saharan Africa 1 subgroup 1 (SSA1-SG1) and 5 (SSA1-SG5, which was most prevalent), and an invasive cryptic species (Mediterranean). SSA1 was infected by five known secondary endosymbionts, Arsenophonus, Cardinium, Hamiltonella, Rickettsia, and Wolbachia, and co-infections with two or three endosymbionts were common. Five begomoviruses, okra enation leaf curl virus, squash leaf curl China virus, tobacco curly shoot virus, tomato leaf curl New Delhi virus, and tomato yellow leaf curl virus, were detected from 43.5% of the B. tabaci samples. However, cassava mosaic disease that causes devastating cassava yield losses was not detected in this study. This study improves the current understanding of the genetic diversity of B. tabaci cryptic species, and it reveals their relationships with endosymbionts and geminiviruses in the cassava and tomato fields of Nigeria.     

Host preference and suitability of some selected crops for two biotypes of Bemisia tabaci in Ghana

The economic importance of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) is mainly due to its wide host range, variable kinds of damage, and great intraspecific variation. The delineation of two African biotypes of this pest has been carried by molecular, ecological, and host‐affiliation approaches, with largely consistent results. However, an understanding of its intricate host–pest interaction is necessary as a basis of its sustainable integrated control. This study investigated the host preference and suitability of cassava and okra biotypes of B. tabaci, based on multiple‐choice landing and oviposition preference assays and stage‐specific survival on eight common whitefly hosts. The cassava biotype significantly preferred cassava, Manihot esculenta, for landing and oviposition, but did not oviposit on okra, Abelmoschus esculentus. The okra biotype preferred okra, oviposited on eggplant, Solanum melongena, tomato, Lycopersicon esculentum, garden egg, Solanum integrifolium, and cowpea, Vigna unguiculata, but did not oviposit on cassava. The okra biotype developed on all hosts except cassava, but only survived marginally on cabbage, Brassica oleracea, and pepper, Capsicum annum var. grosum, while the cassava biotype did not develop on okra, cabbage, or pepper. Thus the observed host acceptance of the two biotypes is wider than earlier reported by host transfer experiments and molecular genetic surveys. Mortality was highest in the first instar nymphal stage, during which total mortality occurred on non‐hosts. Development time was slightly longer on marginal hosts than on the preferred hosts. Cowpea, garden egg, and tomato are additional common hosts of the two biotypes, whose role as reservoir hosts and biotype interbreeding grounds should be investigated further.     

海氏桨角蚜小蜂对两种生物型烟粉虱的功能反应研究

本文报道海氏桨角蚜小蜂Erelmocerus hayati在室内对不同寄主密度下的B型和Q型烟粉虱Bemisiatabaei寄生和取食情况,并比较了该蜂对两种生物型烟粉虱功能反应的差异。结果表明,海氏桨角蚜小蜂对两种生物型烟粉虱的寄生率和致死率可分别达到60％和70％以上,平均每日最大致死量可达40头烟粉虱若虫。该蜂对两种生物型烟粉虱的功能反应曲线符合Holling Ⅱ型,随寄主密度的增加对烟粉虱若虫的寄生和致死数量均增加直至达到每日最大致死数量,而寄生率和致死率则随寄主密度的增加而显著下降。该蜂对两种生物型烟粉虱的功能反应没有显著的差异。     

我国烟粉虱自然种群中存在广泛的Wolbachia感染现象

Wolbachia是广泛分布于节肢动物生殖组织中的细胞质遗传的一类共生菌,可以引起宿主生殖行为的改变.烟粉虱是重要的农业害虫,已有的研究表明烟粉虱中存在Wolbachia的感染,但所检测到的感染率不高,并且迄今在烟粉虱中所检出的Wolbachia均属于B组群.该研究从我国河北、新疆、北京、山东、浙江、广西、海南、广州和福建采集到18个烟粉虱地理种群,首先基于ITS1 rDNA克隆测序鉴定了烟粉虱的生物型,然后采用自行设计的Wolbachia 16S rDNA及wsp基因的专用引物对所采集到的烟粉虱种群进行了分子检测.结果表明几乎所有的烟粉虱自然种群中都存在Wolbachia感染,同时还发现B/Q生物型烟粉虱中主要感染A组群Wolbachia,而非B/Q生物型烟粉虱中存在大量的超感染现象.该研究显示烟粉虱自然种群中Wolbachia的感染率比预想的要高得多,而分子检测方法的灵敏度可能是影响Wolbachia感染率研究的关键因素之一.