Virus-induced gene silencing(VIGS)is a genetic tool used to assess gene function.Tobacco rattle virus(TRV)is a VIGS vector commonly used to induce endogenous gene silencing in plants.However,there is no VIGS system es...Virus-induced gene silencing(VIGS)is a genetic tool used to assess gene function.Tobacco rattle virus(TRV)is a VIGS vector commonly used to induce endogenous gene silencing in plants.However,there is no VIGS system established for Centaurea spp.We evaluated the effectiveness of a TRV-based VIGS system using phytoene desaturase(PDS)as a reporter gene in Centaurea cyanus.Three methods including pressure-,vacuum-and apical meristem-infiltrationwere tested to infect C.cyanus seedlings.Photobleached leaveswere only obtained using apicalmeristem-infiltration after a 14 d treatment.The CcPDS transcripts in photobleached leaves were significantly reduced compared with that in green leaves treated with empty TRV.Four C.cyanus cultivars were tested to detect their VIGS responses,and‘Dwarf Tom Pouce Blue’was the most sensitive.The agro-infiltration condition was optimized by screening for the optimal seedling stage as well as the optimum Agrobacterium density for efficient silencing.Seedlings with four true leaves and infiltration with an Agrobacterium density of OD_(600)0.5 were optimal conditions to obtain more photobleached leaves and more intense photobleached phenotype.The results demonstrated the feasibility of TRV-based VIGS for functional analysis of genes in C.cyanus.展开更多
The aim of this study was to correlate plumage variation with the amount of genomic hybrid content in hybrids between Azure Tits Cyanistes cyanus(Pallas,1770)and European Blue Tit Cyanistes caeruleus(Linnaeus,1758),by...The aim of this study was to correlate plumage variation with the amount of genomic hybrid content in hybrids between Azure Tits Cyanistes cyanus(Pallas,1770)and European Blue Tit Cyanistes caeruleus(Linnaeus,1758),by re-sequencing the genomes of museum specimens of non-hybrids and presumed hybrids with varying plumages.The project was funded by crowdsourcing and initiated when two presumed Azure Tits,observed by hundreds of Swedish birdwatchers,were rejected as hybrids based on minor plumage deviations assumed to indicate hybrid contents from the European Blue Tit.The results confirm that hybrids with intermediate plumages,so called Pleske’s Tits,are first generation hybrids(F1 hybrids).Individuals,whose plumages are similar to Azure Tits,but assessed as hybrids based on minor plumage deviations,are all backcrosses but vary in their degree of hybrid content.However,some individuals morphologically recognized as pure Azure Tits expressed similar degrees of hybrid content.The results indicate that:(1)hybrid content may be widespread in Azure Tits in the western part of its habitat distribution;(2)plumage deviation in backcrosses is not linearly correlated with the genetic degree of hybrid origin;and(3)all Azure Tits observed in Europe outside its natural distribution may have some degree of hybrid origin.We therefore suggest that it is very difficult to phenotypically single out hybrids beyond first generation backcrosses.We argue that decreased sequencing costs and improved analytical tools open the doors for museomic crowd-sourced projects that may not address outstanding biological questions but have a major interest for lay citizens such as birdwatchers.展开更多
Inclusive fitness theory posits that altruistic behaviors,which are directed more likely towards relatives,should be favored by natural selection.However,the prevalence of alternative parenting behaviors in offspring ...Inclusive fitness theory posits that altruistic behaviors,which are directed more likely towards relatives,should be favored by natural selection.However,the prevalence of alternative parenting behaviors in offspring selection,including rejecting their own offspring and accepting the offspring of others,remains poorly understood within the context of parental care evolution.In order to investigate the factors that prompt the occurrence of alternative parenting behaviors,we designed a series of experiments in the Azure-winged Magpie(Cyanopica cyanus).By manipulating the nest spatial position or offspring age/number and parent-offspring familiarity,we addressed how parents provided parental care for the manipulated offspring.In the nest resettlement experiment,the probability of parents rejecting their own offspring significantly increased with nest-moving distances while decreased with offspring ages.In the cross-fostering experiments,the probability of parents provisioning unrelated young significantly decreased with the age difference between cross-fostered chicks.In the nest duplication experiments,where parents were given a choice between familiar offspring and unfamiliar unrelated chicks or between unfamiliar offspring and familiar unrelated chicks,the probability of both alternative parenting behaviors was significantly influenced by the time when parental association with their offspring was deprived.We conclude that as offspring phenotypic traits become individualized and fixed at a special developmental stage,parents gradually acquire the capacity for offspring recognition by associating with them.Any factors that disrupt parent-offspring association or introduce unrelated young into the nest prior to this critical timeline can result in the occurrence of alternative parenting behaviors.展开更多
e coevolutionary arms race between cuckoos and their hosts predicts that low variation in egg features within a host clutch would facilitate discrimination of mimetic parasite eggs.Here,we experimentally examine this ...e coevolutionary arms race between cuckoos and their hosts predicts that low variation in egg features within a host clutch would facilitate discrimination of mimetic parasite eggs.Here,we experimentally examine this prediction by using arti cial and natural parasite eggs showing contrasting level of matching with host eggs.We quanti ed,based on human assessment,intra-clutch variation in egg appearance and egg discrimination in the Iberian Azure-winged Magpie(Cyanopica cyanus),a presumed former host of the Great Spotted Cuckoo(Clamator glandarius).Azure-winged Magpies rejected parasitic eggs in relation to their degree of dissimilarity with own eggs:Great Spotted Cuckoo model eggs were relatively more o en rejected(73.7%) than real Great Spotted Cuckoo eggs(44.4%) and the less contrasting conspeci c eggs(35.5%).Contrary to our predictions,we found that,irrespective of mimicry level of parasitic eggs,intra-clutch variation in host egg appearance did not di er signi cantly between rejecters and acceptors.We found,however,that individuals with higher variation in egg-size were almost signi cantly more prone to be rejecters than individuals showing lower variation in egg size.Our results do not support the hypothesis that the extent of intraclutch variation in egg discrimination varied with parasite egg mimicry in this particular system,and add to previous ndings suggesting that perhaps an increase in intra-clutch variation in egg appearance,rather than a decrease,might be advantageous when discriminating against non-mimetic Great Spotted Cuckoo eggs.展开更多
基金the National Key Research and Development Program(Grant No.2018YFD1000405)the World-Class Discipline Construction and Characteristic Development Guidance Funds for Beijing Forestry University(Grant No.2019XKJS0323),China.
文摘Virus-induced gene silencing(VIGS)is a genetic tool used to assess gene function.Tobacco rattle virus(TRV)is a VIGS vector commonly used to induce endogenous gene silencing in plants.However,there is no VIGS system established for Centaurea spp.We evaluated the effectiveness of a TRV-based VIGS system using phytoene desaturase(PDS)as a reporter gene in Centaurea cyanus.Three methods including pressure-,vacuum-and apical meristem-infiltrationwere tested to infect C.cyanus seedlings.Photobleached leaveswere only obtained using apicalmeristem-infiltration after a 14 d treatment.The CcPDS transcripts in photobleached leaves were significantly reduced compared with that in green leaves treated with empty TRV.Four C.cyanus cultivars were tested to detect their VIGS responses,and‘Dwarf Tom Pouce Blue’was the most sensitive.The agro-infiltration condition was optimized by screening for the optimal seedling stage as well as the optimum Agrobacterium density for efficient silencing.Seedlings with four true leaves and infiltration with an Agrobacterium density of OD_(600)0.5 were optimal conditions to obtain more photobleached leaves and more intense photobleached phenotype.The results demonstrated the feasibility of TRV-based VIGS for functional analysis of genes in C.cyanus.
基金This project was crowd sourced and mainly financed by interested birdwatchers.MI also acknowledge financial support from the Swedish research council(2019-03900)Riksmusei vanner.
文摘The aim of this study was to correlate plumage variation with the amount of genomic hybrid content in hybrids between Azure Tits Cyanistes cyanus(Pallas,1770)and European Blue Tit Cyanistes caeruleus(Linnaeus,1758),by re-sequencing the genomes of museum specimens of non-hybrids and presumed hybrids with varying plumages.The project was funded by crowdsourcing and initiated when two presumed Azure Tits,observed by hundreds of Swedish birdwatchers,were rejected as hybrids based on minor plumage deviations assumed to indicate hybrid contents from the European Blue Tit.The results confirm that hybrids with intermediate plumages,so called Pleske’s Tits,are first generation hybrids(F1 hybrids).Individuals,whose plumages are similar to Azure Tits,but assessed as hybrids based on minor plumage deviations,are all backcrosses but vary in their degree of hybrid content.However,some individuals morphologically recognized as pure Azure Tits expressed similar degrees of hybrid content.The results indicate that:(1)hybrid content may be widespread in Azure Tits in the western part of its habitat distribution;(2)plumage deviation in backcrosses is not linearly correlated with the genetic degree of hybrid origin;and(3)all Azure Tits observed in Europe outside its natural distribution may have some degree of hybrid origin.We therefore suggest that it is very difficult to phenotypically single out hybrids beyond first generation backcrosses.We argue that decreased sequencing costs and improved analytical tools open the doors for museomic crowd-sourced projects that may not address outstanding biological questions but have a major interest for lay citizens such as birdwatchers.
基金provided by the National Natural Sciences Foundation of China (Grant 32071491,31772465,31672299,31572271,and 32260128)。
文摘Inclusive fitness theory posits that altruistic behaviors,which are directed more likely towards relatives,should be favored by natural selection.However,the prevalence of alternative parenting behaviors in offspring selection,including rejecting their own offspring and accepting the offspring of others,remains poorly understood within the context of parental care evolution.In order to investigate the factors that prompt the occurrence of alternative parenting behaviors,we designed a series of experiments in the Azure-winged Magpie(Cyanopica cyanus).By manipulating the nest spatial position or offspring age/number and parent-offspring familiarity,we addressed how parents provided parental care for the manipulated offspring.In the nest resettlement experiment,the probability of parents rejecting their own offspring significantly increased with nest-moving distances while decreased with offspring ages.In the cross-fostering experiments,the probability of parents provisioning unrelated young significantly decreased with the age difference between cross-fostered chicks.In the nest duplication experiments,where parents were given a choice between familiar offspring and unfamiliar unrelated chicks or between unfamiliar offspring and familiar unrelated chicks,the probability of both alternative parenting behaviors was significantly influenced by the time when parental association with their offspring was deprived.We conclude that as offspring phenotypic traits become individualized and fixed at a special developmental stage,parents gradually acquire the capacity for offspring recognition by associating with them.Any factors that disrupt parent-offspring association or introduce unrelated young into the nest prior to this critical timeline can result in the occurrence of alternative parenting behaviors.
文摘e coevolutionary arms race between cuckoos and their hosts predicts that low variation in egg features within a host clutch would facilitate discrimination of mimetic parasite eggs.Here,we experimentally examine this prediction by using arti cial and natural parasite eggs showing contrasting level of matching with host eggs.We quanti ed,based on human assessment,intra-clutch variation in egg appearance and egg discrimination in the Iberian Azure-winged Magpie(Cyanopica cyanus),a presumed former host of the Great Spotted Cuckoo(Clamator glandarius).Azure-winged Magpies rejected parasitic eggs in relation to their degree of dissimilarity with own eggs:Great Spotted Cuckoo model eggs were relatively more o en rejected(73.7%) than real Great Spotted Cuckoo eggs(44.4%) and the less contrasting conspeci c eggs(35.5%).Contrary to our predictions,we found that,irrespective of mimicry level of parasitic eggs,intra-clutch variation in host egg appearance did not di er signi cantly between rejecters and acceptors.We found,however,that individuals with higher variation in egg-size were almost signi cantly more prone to be rejecters than individuals showing lower variation in egg size.Our results do not support the hypothesis that the extent of intraclutch variation in egg discrimination varied with parasite egg mimicry in this particular system,and add to previous ndings suggesting that perhaps an increase in intra-clutch variation in egg appearance,rather than a decrease,might be advantageous when discriminating against non-mimetic Great Spotted Cuckoo eggs.
