Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain...Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont ＂Candidatus Portiera aleyrodidarum＂ and two secondary symbionts ＂Candidatus Hamiltonella defensa＂ and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults （F0） that fed for 48 h on a diet treated with rifampicin at concentrations of 1 100/zg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring （F 1） of the rifampicin-treated adults. Although the F1 adults produced some eggs （F2）, most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects ofrifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.展开更多
Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt...Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt,was recorded in a species of notorious pest whitefly,tentatively named as Asia II 1,from the Bemisia tabaci complex.The role of this Rickettsia in the biology of its host is unknown.Here we investigated the impact of RiTBt on the performance and virus transmission capacity of Asia II 1.RiTBt did not significantly affect the life history parameters of the whitefly when the host insect was reared on tobacco,tomato,and cotton,three host plants with relatively low,medium and high suitability to the whitefly.Intriguingly,RiTBt slightly enhanced whitefly transmission of cotton leaf curl Multan virus(CLCuMuV),a virus that is transmitted by the whitefly in the field and has caused extensive damage to cotton production.Specifically,compared with whiteflies without RiTBt,following a 48 h virus acquisition whiteflies with RiTBt had higher titer of virus and showed higher efficiency of virus transmission.A rickettsial secretory protein BtR242 was identified as a putative virus-binding protein,and was observed to interact with the coat protein of CLCuMuV in vitro.Viral infection of the whitefly downregulated gene transcript levels of the BtR242 gene.These observations indicate that RiTBt has limited impact on the biology of the Asia II 1 whitefly,and whether this symbiont has functions in the biology of other host whiteflies warrants future investigation.展开更多
Identifying cryptic species poses a substantial challenge to both biologists and naturalists due to morphological similarities.Bemisia tabaci is a cryptic species complex containing more than 44 putative species;sever...Identifying cryptic species poses a substantial challenge to both biologists and naturalists due to morphological similarities.Bemisia tabaci is a cryptic species complex containing more than 44 putative species;several of which are currently among the world's most destructive crop pests.Interpreting and delimiting the evolution of this species complex has proved problematic.To develop a comprehensive framework for species delimitation and identification,we evaluated the performance of distinct data sources both individually and in combination among numerous samples of the B.tabaci species complex acquired worldwide.Distinct datasets include full mitogenomes,single-copy nuclear genes,restriction site-associated DNA sequencing,geographic range,host speciation,and reproductive compatibility datasets.Phylogenetically,our well-supported topologies generated from three dense molecular markers highlighted the evolutionary divergence of species of the B.tabaci complex and suggested that the nuclear markers serve as a more accurate representation of B.tabaci species diversity.Reproductive compatibility datasets facilitated the identification of at least 17 different cryptic species within our samples.Native geographic range information provides a complementary assessment of species recognition,while the host range datasets provide low rate of delimiting resolution.We further summarized different data performances in species classification when compared with reproductive compatibility,indicating that combination of mtCOI divergence,nuclear markers,geographic range provide a complementary assessment of species recognition.Finally,we represent a model for understanding and untangling the cryptic species complexes based on the evidence from this study and previously published articles.展开更多
基金This work was financially supported by the National Basic Research Program of China （Project No. 2013 CB 127604） and the National Natural Science Foundation of China （Project No. 31390421）.
文摘Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont ＂Candidatus Portiera aleyrodidarum＂ and two secondary symbionts ＂Candidatus Hamiltonella defensa＂ and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults （F0） that fed for 48 h on a diet treated with rifampicin at concentrations of 1 100/zg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring （F 1） of the rifampicin-treated adults. Although the F1 adults produced some eggs （F2）, most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects ofrifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.
基金We thank Professor Myron Zalucki,The University of Queensland,Australia for editing the final version of the manuscript prior to submission.This work was financially supported by the National Natural Science Foundation of China(Project no.31772173).
文摘Rickettsia consists of some of the most prevalent symbionts of insects and often plays a significant role in the biology of its hosts.Recently,a maternally inherited Torix group Rickettsia,provisionally named as RiTBt,was recorded in a species of notorious pest whitefly,tentatively named as Asia II 1,from the Bemisia tabaci complex.The role of this Rickettsia in the biology of its host is unknown.Here we investigated the impact of RiTBt on the performance and virus transmission capacity of Asia II 1.RiTBt did not significantly affect the life history parameters of the whitefly when the host insect was reared on tobacco,tomato,and cotton,three host plants with relatively low,medium and high suitability to the whitefly.Intriguingly,RiTBt slightly enhanced whitefly transmission of cotton leaf curl Multan virus(CLCuMuV),a virus that is transmitted by the whitefly in the field and has caused extensive damage to cotton production.Specifically,compared with whiteflies without RiTBt,following a 48 h virus acquisition whiteflies with RiTBt had higher titer of virus and showed higher efficiency of virus transmission.A rickettsial secretory protein BtR242 was identified as a putative virus-binding protein,and was observed to interact with the coat protein of CLCuMuV in vitro.Viral infection of the whitefly downregulated gene transcript levels of the BtR242 gene.These observations indicate that RiTBt has limited impact on the biology of the Asia II 1 whitefly,and whether this symbiont has functions in the biology of other host whiteflies warrants future investigation.
基金Peter Sseruwagi and Joseph Ndunguru,Mikocheni Agriculture Research Institute,Tanzania,for collecting samples from Uganda.J.N.C.is supported by grants(AGL2013-48913-C2-1-R and AGL2016-75819-C2-2-R)from the Ministerio de Economia y Competitividad(MINECO,Spain)co-financed by ERDF.E.F.O.is a recipient of a"Juan de la Cierva-Incorporacion"postdoctoral contract from MINECO.
文摘Identifying cryptic species poses a substantial challenge to both biologists and naturalists due to morphological similarities.Bemisia tabaci is a cryptic species complex containing more than 44 putative species;several of which are currently among the world's most destructive crop pests.Interpreting and delimiting the evolution of this species complex has proved problematic.To develop a comprehensive framework for species delimitation and identification,we evaluated the performance of distinct data sources both individually and in combination among numerous samples of the B.tabaci species complex acquired worldwide.Distinct datasets include full mitogenomes,single-copy nuclear genes,restriction site-associated DNA sequencing,geographic range,host speciation,and reproductive compatibility datasets.Phylogenetically,our well-supported topologies generated from three dense molecular markers highlighted the evolutionary divergence of species of the B.tabaci complex and suggested that the nuclear markers serve as a more accurate representation of B.tabaci species diversity.Reproductive compatibility datasets facilitated the identification of at least 17 different cryptic species within our samples.Native geographic range information provides a complementary assessment of species recognition,while the host range datasets provide low rate of delimiting resolution.We further summarized different data performances in species classification when compared with reproductive compatibility,indicating that combination of mtCOI divergence,nuclear markers,geographic range provide a complementary assessment of species recognition.Finally,we represent a model for understanding and untangling the cryptic species complexes based on the evidence from this study and previously published articles.
