The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a worldwide cereal pest with its dispersion to over 30 countries in this century. According to the natural history of its occurrence around the wo...The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a worldwide cereal pest with its dispersion to over 30 countries in this century. According to the natural history of its occurrence around the world, it is postulated RWA originated from western or central Asia. The aphid dispersed gradually to Europe and northern Africa, but its big jump across the ocean to North America is still a mystery. There are two overwintering strategies in RWA. The anholocyclic biotype, often reproducing earlier and more offsprings than the holocyclic one, has greater impact on crops in South Africa and United States. According to the experiments on its thermal response, RWA could withstand temperatures below -20℃, while temperatures above 30℃ would be harmful to its survival. The preference to colder condition may determine its distribution on the world. RWA has made great damages to cereal crops worldwide. It caused loss in crop yield by directly feeding on plant nutrition and disturbing the plant metabolism. But its status as plant virus transporter is open to question. By now, the aphid is still a serious pest in many countries and its invasion to more countries and areas maybe continues. Therefore, the research on its biological characteristics as well as its dispersion apparently needs to be enhanced in the future.展开更多
Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contrib...Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contributes to the evolutionary success of this pest.However,the related molecular basis remains unclear.Here,we identified the effects of postnatal crowding on wing morph determination in cotton aphid,and examined the transcriptomic differences between wingless and wing morphs.Results:Effect of postnatal crowding on wing determination in A gossypii was evaluated firstly.Under the density of 5 nymphs·cm-2,no wing aphids appeared.Proportion of wing morphs rised with the increase of density in a certain extent,and peaked to 56.1% at the density of 20 nymphs·cm-2,and reduced afterwards.Then,transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs,in which 3 126 and 3 392 unigenes annotated in Nr(Non-redundant protein sequence) database were found in wingless or wing morphs exclusively.Moreover,3 187 up-and 1 880 down-regulated genes were identified in wing versus wingless aphid.Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination,including lipid catabolic and metabolism,insulin,ecdysone and juvenile hormone biosynthesis.The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR) soon afterwards.Conclusions:The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A gossypii was 20 nymphs·cm-2.Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph,respectively.Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.展开更多
The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), was a worldwide cereal pest. The control measures to this pest were reviewed, emphasizing on natural enemies and plant resistance. First, spring wheat with e...The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), was a worldwide cereal pest. The control measures to this pest were reviewed, emphasizing on natural enemies and plant resistance. First, spring wheat with earlier planting dates had higher yield and could resist RWA infestation to a more extent, while winter wheat with later planting dates could escape infestation of Russian wheat aphid with very few exceptions. So, manipulation of wheat planting dates was suggested in worldwide scale for the aphid control. Second, the natural enemies were considered as the most important factor to reduced the pest status. Introduced and native natural enemies were evaluated for their potential as biological agents in South Africa, United States, and Australia. In South Africa, an introduced parasitoid and a predator were selected for releasing. In the United States, the project on exploring and releasing the natural enemies was unprecedented in biological control history. The endeavor in USA has been proved primarily successful today and will be afterward. The RWA control in Chile was considered most successful, partly because of their introduction of natural enemies before the aphid arrival. The native enemies together with other factors in central Asia and Europe apparently suppressed the aphids to a low level. The screen for resistant wheat was another important research project in fighting with RWA. In South Africa and USA, resistant wheat and barley were bred, and some of them had been put in commercial use for RWA control. The overwhelming mechanisms in resistant wheat varieties were antibiosis, tolerance or their combination. Though chemical insecticide spraying was proved as an effective method for aphid control, more and more research has switched from this method to non chemical control measures as required by IPM. Future research should put more emphasis on augmentation of the natural enemies, revealing the relationship between RWA and agricultural ecosystem and integration of all effective measures.展开更多
Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic...Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic female(WLPF).Most studies on A.gossypii have focused on WPF,while few have investigated GP and male.The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A.gossypii remains unknown.The wing differentiation of WPF was explored in a previous study.Herein,GP and male were induced indoors.The characters of the body,internal genitals,wing veins,and fecundity of GP and male were compared with those of WPF or WLPF.Compared with WLPF,the shared and separate differentially expressed genes(DEGs)were identified in these three-wing morphs.Results:Newly-born nymphs reared in short photoperiod condition(8 L:16D,18°C)exclusively produced gynoparae(GPe)and males in adulthood successively,in which the sex ratio was GP biased.A total of 14 GPe and 9 males were produced by one mother aphid.Compared with WLPF,the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore-and underwings,reproductive system,and fecundity.A total of 37090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing(RNA-Seq).In addition,10867 and 19334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF,respectively.Compared with WLPF,the winged morphs demonstrated 2335 shared DEGs(1658 upregulated and 677 downregulated).The 1658 shared upregulated DEGs were enriched in multiple signaling pathways,including insulin,FoxO,MAPK,starch and sucrose metabolism,fatty acid biosynthesis,and degradation,suggesting their key roles in the regulation of wing plasticity in the cotton aphid.Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR).The comparison concurred with the expression pattern(either up-or downregulated)and supported the accuracy and reliability of RNA-Seq.Finally,the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.Conclusions:The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions(8 L:16D,18°C).The external morphological characters,especially wing vein patterns,were similar among WPFs,GPe,and males.However,their reproductive organs were strikingly different.Compared with WLPF,shared(2335)and exclusively(1470 in WLPF,2419 in GP,10774 male)expressed genes were identified in the three-wing morphs through RNA-Seq,and several signaling pathways that are potentially involved in their wing differentiation were obtained,including insulin signaling,starch and sucrose metabolism.展开更多
文摘The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), has become a worldwide cereal pest with its dispersion to over 30 countries in this century. According to the natural history of its occurrence around the world, it is postulated RWA originated from western or central Asia. The aphid dispersed gradually to Europe and northern Africa, but its big jump across the ocean to North America is still a mystery. There are two overwintering strategies in RWA. The anholocyclic biotype, often reproducing earlier and more offsprings than the holocyclic one, has greater impact on crops in South Africa and United States. According to the experiments on its thermal response, RWA could withstand temperatures below -20℃, while temperatures above 30℃ would be harmful to its survival. The preference to colder condition may determine its distribution on the world. RWA has made great damages to cereal crops worldwide. It caused loss in crop yield by directly feeding on plant nutrition and disturbing the plant metabolism. But its status as plant virus transporter is open to question. By now, the aphid is still a serious pest in many countries and its invasion to more countries and areas maybe continues. Therefore, the research on its biological characteristics as well as its dispersion apparently needs to be enhanced in the future.
基金funded by National Natural Science Foundation of China(No.31572015)
文摘Background:Aphis gossypii is a worldwide sap-sucking pest with a variety of hosts and a vector of more than 50 plant viruses.The strategy of wing polyphenism,mostly resulting from population density increasing,contributes to the evolutionary success of this pest.However,the related molecular basis remains unclear.Here,we identified the effects of postnatal crowding on wing morph determination in cotton aphid,and examined the transcriptomic differences between wingless and wing morphs.Results:Effect of postnatal crowding on wing determination in A gossypii was evaluated firstly.Under the density of 5 nymphs·cm-2,no wing aphids appeared.Proportion of wing morphs rised with the increase of density in a certain extent,and peaked to 56.1% at the density of 20 nymphs·cm-2,and reduced afterwards.Then,transcriptomes of wingless and wing morphs were assembled and annotated separately to identify potentially exclusively or differentially expressed transcripts between these two morphs,in which 3 126 and 3 392 unigenes annotated in Nr(Non-redundant protein sequence) database were found in wingless or wing morphs exclusively.Moreover,3 187 up-and 1 880 down-regulated genes were identified in wing versus wingless aphid.Pathways analysis suggested the involvement of differentially expressed genes in multiple cellular signaling pathways involved in wing morphs determination,including lipid catabolic and metabolism,insulin,ecdysone and juvenile hormone biosynthesis.The expression levels of related genes were validated by the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR) soon afterwards.Conclusions:The present study identified the effects of postnatal crowding on wing morphs induction and demonstrated that the critical population density for wing morphs formation in A gossypii was 20 nymphs·cm-2.Comparative transcriptome analysis provides transcripts potentially expressed exclusively in wingless or wing morph,respectively.Differentially expressed genes between wingless and wing morphs were identified and several signaling pathways potentially involved in cotton aphid wing differentiation were obtained.
文摘The Russian wheat aphid (RWA), Diuraphis noxia (Mordvilko), was a worldwide cereal pest. The control measures to this pest were reviewed, emphasizing on natural enemies and plant resistance. First, spring wheat with earlier planting dates had higher yield and could resist RWA infestation to a more extent, while winter wheat with later planting dates could escape infestation of Russian wheat aphid with very few exceptions. So, manipulation of wheat planting dates was suggested in worldwide scale for the aphid control. Second, the natural enemies were considered as the most important factor to reduced the pest status. Introduced and native natural enemies were evaluated for their potential as biological agents in South Africa, United States, and Australia. In South Africa, an introduced parasitoid and a predator were selected for releasing. In the United States, the project on exploring and releasing the natural enemies was unprecedented in biological control history. The endeavor in USA has been proved primarily successful today and will be afterward. The RWA control in Chile was considered most successful, partly because of their introduction of natural enemies before the aphid arrival. The native enemies together with other factors in central Asia and Europe apparently suppressed the aphids to a low level. The screen for resistant wheat was another important research project in fighting with RWA. In South Africa and USA, resistant wheat and barley were bred, and some of them had been put in commercial use for RWA control. The overwhelming mechanisms in resistant wheat varieties were antibiosis, tolerance or their combination. Though chemical insecticide spraying was proved as an effective method for aphid control, more and more research has switched from this method to non chemical control measures as required by IPM. Future research should put more emphasis on augmentation of the natural enemies, revealing the relationship between RWA and agricultural ecosystem and integration of all effective measures.
基金Central Public-interest Scientific Institution Basal Research Fund(No.1610162019020604).
文摘Background:The worldwide pest Aphis gossypii has three-winged morphs in its life cycle,namely,winged parthenogenetic female(WPF),winged gynopara(GP),and winged male,which are all produced by a wingless parthenogenetic female(WLPF).Most studies on A.gossypii have focused on WPF,while few have investigated GP and male.The shared molecular mechanism underlying the wing differentiation in the three wing morphs of A.gossypii remains unknown.The wing differentiation of WPF was explored in a previous study.Herein,GP and male were induced indoors.The characters of the body,internal genitals,wing veins,and fecundity of GP and male were compared with those of WPF or WLPF.Compared with WLPF,the shared and separate differentially expressed genes(DEGs)were identified in these three-wing morphs.Results:Newly-born nymphs reared in short photoperiod condition(8 L:16D,18°C)exclusively produced gynoparae(GPe)and males in adulthood successively,in which the sex ratio was GP biased.A total of 14 GPe and 9 males were produced by one mother aphid.Compared with WLPF,the three-wing morphs exhibited similar morphology and wing vein patterns but were obviously discriminated in the length of fore-and underwings,reproductive system,and fecundity.A total of 37090 annotated unigenes were obtained from libraries constructed using the four morphs via RNA sequencing(RNA-Seq).In addition,10867 and 19334 DEGs were identified in the pairwise comparison of GP versus WLPF and male versus WLPF,respectively.Compared with WLPF,the winged morphs demonstrated 2335 shared DEGs(1658 upregulated and 677 downregulated).The 1658 shared upregulated DEGs were enriched in multiple signaling pathways,including insulin,FoxO,MAPK,starch and sucrose metabolism,fatty acid biosynthesis,and degradation,suggesting their key roles in the regulation of wing plasticity in the cotton aphid.Forty-four genes that spanned the range of differential expression were chosen to validate statistical analysis based on RNA-Seq through the reverse transcription quantitative real time polymerase chain reaction(RT-qPCR).The comparison concurred with the expression pattern(either up-or downregulated)and supported the accuracy and reliability of RNA-Seq.Finally,the potential roles of DEGs related to the insulin signaling pathway in wing dimorphism were discussed in the cotton aphid.Conclusions:The present study established an efficiently standardized protocol for GP and male induction in cotton aphid by transferring newly-born nymphs to short photoperiod conditions(8 L:16D,18°C).The external morphological characters,especially wing vein patterns,were similar among WPFs,GPe,and males.However,their reproductive organs were strikingly different.Compared with WLPF,shared(2335)and exclusively(1470 in WLPF,2419 in GP,10774 male)expressed genes were identified in the three-wing morphs through RNA-Seq,and several signaling pathways that are potentially involved in their wing differentiation were obtained,including insulin signaling,starch and sucrose metabolism.
