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Jose Luis Cenis - One of the best experts on this subject based on the ideXlab platform.
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biotype q of bemisia tabaci identified in israel
Phytoparasitica, 2003Co-Authors: A. R. Horowitz, Ian Denholm, Kevin Gorman, Jose Luis Cenis, Svetlana Kontsedalov, Isaac IshaayaAbstract:The biotype status of samples of the whiteflyBemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) collected from several field and greenhouse sites in Israel during 1999–2000 was determined by polyacrylamide gel electrophoresis (PAGE) for general esterases, and by RAPD-PCR using primers of arbitrary sequence. Results of this survey provide the first published evidence for the occurrence of theB. tabaci Q biotype, alongside the more widely distributed B biotype. Based on the collected samples, it appears that both the B and Q Biotypes are present in Israel, and that field populations consist of a mixture of the two Biotypes. A possible link betweenB. tabaci Biotypes and insecticide resistance is discussed.
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genetic diversity of iberian populations of bemisia tabaci hemiptera aleyrodidae based on random amplified polymorphic dna polymerase chain reaction
Molecular Ecology, 2001Co-Authors: Andres Moya, P Guirao, D Cifuentes, Francisco Beitia, Jose Luis CenisAbstract:: The genetic structure of six Iberian populations of the whitefly Bemisia tabaci, two of them biotype Q, one biotype B, and the other three a mixture of both, has been studied using random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). A total of 336 individuals was completely discriminated by means of 234 scored bands. Separate analyses of molecular variance of haploid males and diploid females using the pairwise number of differences between haplotypes showed that Biotypes contribute significantly more to the observed variability than populations within Biotypes. On average, gene flow between two Biotypes of the same population is lower than between populations of identical Biotypes. On the basis of these results and the nondetection under natural conditions of a single hybrid, we consider that both Biotypes are genetically isolated under the ecological conditions prevailing in the south Iberian Peninsula. All populations of biotype Q presented similar values of intrapopulational diversity, which were higher than the values shown by populations of biotype B.
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genetic relationships among Biotypes of bemisia tabaci hemiptera aleyrodidae based on aflp analysis
Bulletin of Entomological Research, 2000Co-Authors: Maria Teresa Cervera, Francisco Beitia, Jose Antonio Cabezas, B Simon, Jose M Martinezzapater, Jose Luis CenisAbstract:Genetic similarities between 13 samples belonging to nine reference Biotypes and two field populations of Bemisia tabaci (Gennadius), one field population of B. medinae Gomez-Menor and another of B. afer Priesner & Hosny, were evaluated using amplified fragment length polymorphism (AFLP) markers. The results indicate that B. tabaci Biotypes can be grouped together with a minimum similarity coefficient of 0.32 and separated from the two other species with a similarity coefficient of 0.07. Bemisia tabaci Biotypes were grouped in four clusters which comprised: (i) Near East and Indian subcontinent Biotypes; (ii) B and Q Biotypes plus a Nigerian population from cowpea; (iii) New World A biotype; and (iv) S biotype and a Nigerian population from cassava. These results were consistent with a previous grouping of Biotypes based on RAPD-PCR analysis. The AFLP assay allowed the scoring of a total of 354 polymorphic bands in two reaction events with the use of two primer combinations.
Shai Morin - One of the best experts on this subject based on the ideXlab platform.
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evidence for pre zygotic reproductive barrier between the b and q Biotypes of bemisia tabaci hemiptera aleyrodidae
Bulletin of Entomological Research, 2010Co-Authors: Moshe Elbaz, N Lahav, Shai MorinAbstract:: The degree of reproductive isolation between the B and Q Biotypes of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is currently not clear. Laboratory experiments have shown that the two Biotypes are capable of producing viable F1 hybrids but that these females are sterile as their F2 generation failed to develop, indicating, most likely, a post-zygotic reproductive barrier. Here, we confirm, by molecular and ecological tools, that the B and Q Biotypes of Israel are genetically isolated and provide two independent lines of evidence that support the existence of a pre-zygotic reproductive barrier between them. Firstly, monitoring of mating behaviors in homogeneous and heterogeneous couples indicated no copulation events in heterogeneous couples compared to approximately 50% in homogeneous B and Q couples. Secondly, we could not detect the presence of sperm in the spermathecae of females from heterogeneous couples, compared to 50% detection in intra-B biotype crosses and 15% detection in intra-Q biotype crosses. The existence of pre-zygotic reproductive barriers in Israeli B and Q colonies may indicate a reinforcement process in which mating discrimination is strengthened between sympatric taxa that were formerly allopatric, to avoid maladaptive hybridization. As the two Biotypes continued to perform all courtship stages prior to copulation, we also conducted mixed cultures experiments in order to test the reproductive consequences of inter-biotype courtship attempts. In mixed cultures, a significant reduction in female fecundity was observed for the Q biotype but not for the B biotype, suggesting an asymmetric reproductive interference effect in favour of the B biotype. The long-term outcome of this effect is yet to be determined since additional environmental forces may reduce the probability of demographic displacement of one biotype by the other in overlapping niches.
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multiple origins of pyrethroid resistance in sympatric Biotypes of bemisia tabaci hemiptera aleyrodidae
Insect Biochemistry and Molecular Biology, 2006Co-Authors: Michal Alon, Juergen Benting, Bettina Lueke, Tanja Ponge, Fishel Alon, Shai MorinAbstract:Abstract The two most damaging Biotypes of Bemisia tabaci , B and Q, are sympatric in the Mediterranean basin and show high resistance to pyrethroids synergized by organophosphates. Previous work showed that in the B biotype, this resistance is associated with the L925I mutation in the para -type voltage gated sodium channel. Here we identified two mutations in the para -type voltage gated sodium channel associated with resistance to pyrethroids synergized by organophosphates in the Q biotype: the L925I mutation that occurs in the B biotype, and substitution of threonine to valine, at position 929 (T929V). To determine if the L925I and T929V mutations have single or multiple origins, we sequenced the DNA regions flanking the mutations from 13 B and Q strains collected worldwide. The survey identified five resistant alleles and five susceptible alleles. In the resistant alleles, the nucleotide diversity was low within Biotypes (0.001), but high between Biotypes (0.033). Nucleotide diversity in susceptible alleles was high between the two Biotypes (0.028). These observations are consistent with multiple independent origins of resistance. Although the B and Q Biotypes coexist in several regions of the Mediterranean basin, divergence in their DNA sequences at the para -type voltage gated sodium channel locus suggests gene flow between these Biotypes is low or nil.
Youjun Zhang - One of the best experts on this subject based on the ideXlab platform.
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the suitability of Biotypes q and b of bemisia tabaci gennadius hemiptera aleyrodidae at different nymphal instars as hosts for encarsia formosa gahan hymenoptera aphelinidae
PeerJ, 2016Co-Authors: Youjun Zhang, Qingjun Wu, Shaoli WangAbstract:Encarsia formosa Gahan (Hymenoptera: Aphelinidae) is a solitary endoparasitoid that is commercially reared and released for augmentative biological control of whiteflies infesting greenhouse crops. In most areas in China, the invasive and destructive whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) biotype Q has replaced B. tabaci biotype B and has become dominant between the two. A better understanding of the suitability of different nymphal instars of B. tabaci Biotypes Q and B as hosts for E. formosa is needed to improve the use of this parasitoid for biological control. Parasitism of the four nymphal instars of B. tabaci Biotypes Q and B by the commercial strain of E. formosa mass reared on Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) was assessed in the laboratory. The results indicated that E. formosa parasitized and successfully developed on all instars of both Biotypes but performed best on the 3rd instar of B. tabaci biotype B and on the 2nd, 3rd, and 4th instars of B. tabaci biotype Q. The host-feeding rate of the adult parasitoid was generally higher on nymphal instars of B. tabaci biotype Q than on the corresponding nymphal instars of biotype B and was significantly higher on the 2nd and 3rd instars. For both whitefly Biotypes, the parasitoid’s immature developmental period was the longest on the 1st instar, intermediate on the 2nd and 3rd instars, and the shortest on the 4th instar. The parasitoid emergence rate was significantly lower on the 1st instar than on the other three instars and did not significantly differ between B. tabaci biotype B and biotype Q. Offspring longevity was greater on the 3rd and 4th instars than on the 1st instar and did not significantly differ between the two B. tabaci Biotypes. The results indicate that commercially-produced E. formosa can parasitize all instars of B. tabaci Biotypes B and Q, making this parasitoid a promising tool for the management of the two Biotypes of B. tabaci present in China.
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further insights into the strange role of bacterial endosymbionts in whitefly bemisia tabaci comparison of secondary symbionts from Biotypes b and q in china
Bulletin of Entomological Research, 2011Co-Authors: D Chu, Youjun Zhang, C S Gao, P J De Barro, F H Wan, I A KhanAbstract:The percentage infection of secondary symbionts (SS) (Wolbachia, Arsenophonus, Rickettsia, Hamiltonella, Fritschea and Cardinium) in the exotic Bemisia tabaci (Genn.) invaders, commonly known as Biotypes B and Q from China, were determined by PCR. In total, 373 biotype B and 1830 biotype Q individuals were screened for the presence of SS. Biotype B was more abundant than biotype Q from 2005 to 2006, and biotype Q was more abundant from 2007 to 2009. Each of the SS, with the exception of Fritschea, was detected in both Biotypes B and Q; Fritschea was found in none of the samples examined. For biotype B, the percentage infection of Hamiltonella was the highest (92.0%) followed by Rickettsia (70.2%). For biotype Q, the percentage infection of Hamiltonella was again the highest (73.3%). Arsenophonus was the least common of the SS observed in both Biotypes B and Q. The percentage infection of Wolbachia, Rickettsia and Hamiltonella in biotype B was each significantly higher than in biotype Q, whereas the percentage infection of Cardinium in biotype B was significantly lower than in biotype Q. The percentage infection of SS in Biotypes B and Q varied from year to year over the period 2005-2009. Furthermore, within biotype Q, two distinct subgroups were identified which differ from each other in terms of their SS complement. We discuss these results in the light of the potentially influential factors and roles of the SS.
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further spread of and domination by bemisia tabaci hemiptera aleyrodidae biotype q on field crops in china
Journal of Economic Entomology, 2011Co-Authors: Daqing Ge, Qingjun Wu, Shaoli Wang, Xiaoguo Jiao, Xin Yang, Nina Yang, Qi Su, Baoyun Xu, Youjun ZhangAbstract:The sweetpotato whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), causes severe crop losses to many crops. The worst of these losses are often associated with the invasion and establishment of Biotypes B and Q of this pest. Previous research in 2007 showed that biotype Q occurred with other Biotypes in most field populations in China. To determine the current status of the biotype composition in the field, an extensive survey covering mainly eastern parts of China was conducted in 2009. Using polymerase chain reaction primers specific for the mitochondrial cytochrome oxidase I of Biotypes B and Q and gene sequencing, we determined the Biotypes composition in 61 whitefly populations and their distribution across 19 provinces in China. Our research revealed that only Biotypes B and Q have been found in the field in 2009 in China. Among them, biotype Q was dominant in 44 locations (100.0%) and biotype B was dominant in 17 locations (100.0%). The current survey indicates that biotype Q has rapidly displaced biotype B in most locations in China.
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change in the biotype composition of bemisia tabaci in shandong province of china from 2005 to 2008
Environmental Entomology, 2010Co-Authors: Youjun Zhang, Judith K BrownAbstract:ABSTRACT Certain Biotypes of the Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) complex cause extensive damage and are important pests and virus vectors in agricultural crops throughout the world. Among the most invasive and well studied are the B and Q Biotypes. Recent reports in Shandong Province, China, have indicated that the Q biotype was introduced there in ≈ 2005, whereas the B biotype has been established there for ∼10 yr. Even so, the present distribution of the two Biotypes in Shandong has not been examined. The results of this study showed that the B and Q Biotypes are both present in Shandong Province based on bar-coding using a ≈450-base fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene. In addition, a B biotype-specific polymerase chain reaction primer pair that amplifies a ≈300 bp mtCOI fragment was designed and used to examine the biotype composition of B. tabaci in selected crops from six provincial locations, using the general mtCOI primers as an internal positive cont...
I Ishaaya - One of the best experts on this subject based on the ideXlab platform.
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dynamics of Biotypes b and q of the whitefly bemisia tabaci and its impact on insecticide resistance
Pest Management Science, 2014Co-Authors: Abraham Rami Horowitz, I IshaayaAbstract:BACKGROUND: The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a key pest in many agricultural crops, including vegetables, ornamentals and field crops. B. tabaci is known for its genetic diversity, which is expressed in a complex of Biotypes or, as recently suggested, a complex of distinct cryptic species. The Biotypes are largely differentiated on the basis of biochemical or molecular polymorphism and differ in characteristics such as host plant range, attraction by natural enemies, secondary symbionts and expression of insecticide resistance. An extensive survey of B. tabaci Biotypes and their impact on insecticide resistance was conducted from 2003 to 2012 in cotton fields and other crops from several locations in Israel. RESULTS: Two Biotypes of B. tabaci, B and Q, were identified, and some differences in the biotype dynamics were recorded from different areas. In northern Israel from 2003 to 2007, a higher proportion of the B biotype was consistently found in early season. However, by the end of the season a definite rise of the Q biotype was sampled, ranging from 60 to 100%, along with high resistance to the insect growth regulator (IGR) pyriproxyfen and to a lesser extent to the neonicotinoid insecticides. In fields located in the central part of Israel, the Q biotype was predominant throughout the seasons, with high resistance to pyriproxyfen. Since 2009, a significant shift in the biotype ratios has been observed: the B biotype has come to predominate over the Q biotype ranging up to 90% or more in most fields. At the same time, resistance to the IGR pyriproxyfen was reduced considerably. CONCLUSION: The possible reasons for the change in the dynamics of B. tabaci Biotypes, and its implications for resistance management, are discussed. Strong B. tabaci resistance to pyriproxyfen in Israel has been associated with the Q rather than with the B biotype. The B biotype is more competitive than the Q biotype under untreated conditions. Reduction in the acreage of cotton fields during recent years, along with a decrease in insecticide use, especially pyriproxyfen, has resulted in the expansion of the B biotype. © 2014 Society of Chemical Industry
G Lushai - One of the best experts on this subject based on the ideXlab platform.
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mitochondrial dna sequence divergence among greenbug homoptera aphididae Biotypes evidence for host adapted races
Insect Molecular Biology, 2000Co-Authors: K A Shufran, John D Burd, James A Anstead, G LushaiAbstract:The full complement of known greenbug, Schizaphis graminum (Rondani), Biotypes found in the USA were subjected to a molecular phylogenetic analysis based on a 1.2-kb portion of the cytochrome oxidase I mitochondrial gene. In addition to these nine Biotypes (B, C, E, F, G, H, I, J and K), a probable isolate of the enigmatic biotype A (NY), a 'new biotype' collected from Elymus canadensis (L.) (CWR), and an isolate from Germany (EUR) were included. Schizaphis rotundiventris (Signoret) was included as an outgroup. Genetic distances among S. graminum Biotypes ranged from 0.08% to 6.17% difference in nucleotide substitutions. Neighbour-joining, maximum parsimony and maximum likelihood analyses all produced dendrograms revealing three clades within S. graminum. Clade 1 contained the 'agricultural' Biotypes commonly found on sorghum and wheat (C, E, K, I, plus J) and there were few substitutions among these Biotypes. Clade 2 contained F, G and NY, and Clade 3 contained B, CWR and EUR, all of which are rarely found on crops. The rarest biotype, H, fell outside the above clades and may represent another Schizaphis species. S. graminum Biotypes are a mixture of genotypes belonging to three clades and may have diverged as host-adapted races on wild grasses.