Huanglongbing(HLB) is a devastating disease that has led to an acute crisis for growers of citrus, one of the world's most important fruit crops. The phloem-feeding Asian citrus psyllid(ACP), Diaphorina citri, is ...Huanglongbing(HLB) is a devastating disease that has led to an acute crisis for growers of citrus, one of the world's most important fruit crops. The phloem-feeding Asian citrus psyllid(ACP), Diaphorina citri, is the main pest at the new shoot stage and is the only natural vector of HLB pathogenic bacteria. Little is known about how plants perceive and defend themselves from this destructive pest. Here, we characterized changes in the expression of various genes in citrus plants that were continuously infested by D. citri for different durations(12, 24, and 48 h). A total of 5 219 differentially expressed genes(DEGs) and 643 common DEGs were identified across all time points. Several pathways related to defense were activated, such as peroxisome, alpha-linolenic acid metabolism, and phenylpropanoid and terpenoid biosynthesis, and some pathways related to growth and signal transduction were suppressed in response to D. citri infestation. The expression of genes including kinases(CML44, CIPK6, and XTH6), phytohormones(SAMT, LOX6, and NPR3), transcription factors(bHLH162, WRKY70, and WRKY40), and secondary metabolite synthesis-related genes(PAL, 4CL2, UGT74B1 and CYP82G1) was significantly altered in response to D. citri infestation. The findings of this study greatly enhance our understanding of the mechanisms underlying the defense response of citrus plants to D. citri infestation at the molecular level. Functional characterization of the candidate defense-related genes identified in this study will aid the molecular breeding of insect-resistant citrus varieties.展开更多
In order to promote the healthy and sustainable development of citrus industry in Guangxi and reduce the harm of Diaphorina citri and citrus Huanglongbing on citrus industry,the paper summarizes the occurrence of D.ci...In order to promote the healthy and sustainable development of citrus industry in Guangxi and reduce the harm of Diaphorina citri and citrus Huanglongbing on citrus industry,the paper summarizes the occurrence of D.citri in Guangxi,and put forward comprehensive control technique,so as to provide the reference for guiding prevention and control of major pests in citrus industry.展开更多
Diaphorina citri is an important vector of Citrus Huanglongbing(HLB)disease.After feeding on young host plant shoots,the population of D.citri can increase significantly.Females also only lay eggs on young shoots.Howe...Diaphorina citri is an important vector of Citrus Huanglongbing(HLB)disease.After feeding on young host plant shoots,the population of D.citri can increase significantly.Females also only lay eggs on young shoots.However,there are few studies on the mechanism of this phenomenon.Exogenous nutrient signals can affect the insulin signaling system of D.citri after feeding on young shoots.In this study,the expression of upstreamfactors DclLPl,DclLP2,and DclR in the insulin signaling system of D.citri was upregulated after feeding on young shoots.After being silenced by RNA interference technology,the results showed that the number of oviposited eggs of D.citri was significantly decreased and the ovarian development was inhibited with severe vacuolation.In addition,detection using quantitative reverse transcription-polymerase chain reaction showed that the upstream regulatory gene DcRheb of the target of rapamycin(TOR)pathway and the downstream reproduction-related DcVg gene were also significantly downregulated.These results suggest that feeding upon young shoots may upregulate the expression levels of upstream factors DclLPl,DclLP2,and DclR in the insulin signaling system.The signal will be through upregulating the expression of DcRheb,an upstream gene of the TOR signaling pathway.This in turn influences yolk metabolism,which eventually causes the ovaries of female D.citri to mature and therefore initiate oviposition behavior.展开更多
The Asian citrus psyllid,Diaphorina citri Kuwayama,is among the most im-portant pests of citrus.It is the main vector of the Huanglongbing(HLB)pathogen Can-didatus Liberibacter asiaticus(CLas),which causes severe loss...The Asian citrus psyllid,Diaphorina citri Kuwayama,is among the most im-portant pests of citrus.It is the main vector of the Huanglongbing(HLB)pathogen Can-didatus Liberibacter asiaticus(CLas),which causes severe losses in citrus crops.Control of D.citri is therefore of paramount importance to reduce the spread of HLB.In this re-gard,using RNA interference(RNAi)to silence target genes is a useful strategy to control psyllids.In this study,using RNAi,we examined the biological functions of the V-ATPase subunit E(V-ATP-E)gene of D.citri,including its effect on acquisition of CLas.The amino acid sequence of V-ATP-E from D.citri had high homology with proteins from other insects.V-ATP-E was expressed at all D.citri life stages analyzed,and the expres-sion level in mature adults was higher than that of teneral adults.Silencing of V-ATP-E resulted in a significant increase in mortality,reduced body weight,and induced cell apop-tosis of the D.citri midgut.The reduced expression of V-ATP-E was indicated to inhibit CLas passing through the midgut and into the hemolymph,leading to a majority of CLas being confined to the midgut.In addition,double-stranded RNA of D.citri V-ATP-E was safe to non-target parasitic wasps.These results suggest that V-ATP-E is an effective RNAi target that can be used in D.citri control to block CLas infection.展开更多
The Asian citrus psyllid,Diaphorina citri is the principal vector of huanglongbing,which transmits Candidatus Liberibacter asiaticus.Trehalase is a key enzyme involved in trehalose hydrolysis and plays an important ro...The Asian citrus psyllid,Diaphorina citri is the principal vector of huanglongbing,which transmits Candidatus Liberibacter asiaticus.Trehalase is a key enzyme involved in trehalose hydrolysis and plays an important role in insect growth and development.The specific functions of this enzyme in D.citri have not been determined.In this study,three trehalase genes(DcTreJ-1,DcTrel-2,and DcTre2)were identified based on the D.citri genome database.Bioinformatic analysis showed that DcTrel-1 and DcTrel-2 are related to soluble trehalase,whereas DcTre2 is associated with membrane-bound trehalase.Spatiotemporal expression analysis indicated that DcTrel-1 and DcTrel-2 had the highest expression levels in the head and wing,respectively,and DcTre2 had high expression levels in the fat body.Furthermore,DcTrel-1 and DcTrel-2 expression levels were induced by 20-hydroxyecdysone and juvenile hormone III,but DcTre2 was unaffected.The expression levels of DcTrel-1,DcTrel-2,and DcTre2 were significantly up-regulated,which resulted in high mortality after treatment with validamycin.Trehalase activities and glucose contents were downregulated,but the trehalose content increased after treatment with validamycin.In addition,the expression levels of chitin metabolism-related genes significantly decreased at 24 and 48 h after treatment with validamycin.Furthermore,silencing of DcTrel-1,DcTrel-2,and DcTre2 reduced the expression levels of chitin metabolism-related genes and led to a malformed phenotype of D.citri.These results indicate that D.citri trehalase plays an essential role in regulating chitin metabolism and provides a new target for control of D.citri.展开更多
The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the...The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the tolerance of psyllids to freezing temperatures needs to be investigated.While mortality of D.citri to cold temperature has been previously studied,much less is known regarding the acclimation potential of psyllids to cold temperatures.We first evaluated cold resistance of D.citri depending on color morph and sex.Subsequently,we compared mortality of D.citri at−4°C for 10 hours between unacclimated psyllids,psyllids that were gradually acclimated to cold over 1 or 2 weeks,and psyllids intermittently acclimated also for 1 or 2 weeks.We did not find major differences in cold resistance between color morphs and sex.We found that after 1 week of gradual acclimation,the survival of psyllids at−4°C increased to 86%,compared to 20%in the control group.Survival did not increase after the second week of gradual acclimation.Although intermittent acclimation improved survival compared to the control group,it was less effective than gradual acclimation with a survival at 30%and 70%after 1 and 2 weeks of acclimation,respectively,although this difference with gradual acclimation was not significant at week 2.These data show that gradual cold acclimation allows D.citri to survive brief periods below freezing.It may serve as a mechanism responsible for increasing northern establishment of this pest.展开更多
Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in ...Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in abnormal phenotypes.However,the mechanism of validamycin's action on D.citri remains unclear.Here,using a comparative transcriptome analysis,464 differentially expressed genes(DEGs)in D.citri were identified after validamycin treatment.A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in“small molecule process”,“structural molecule ac-tivity”and“transition metal ion binding”.DEGs involved in chitin metabolism,cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction.The RNA interference of D.citri chitinase-like protein EN03 and D.citri cuticle protein 7 genes significantly affected D.citri molting.Moreover,the recombinant chitinase-like protein EN03 exhibited a chitin-binding property,and an antimicrobial activity against Bacillus subtilis.This study provides a first insight into the molecular changes in D.citri after exposure to validamycin and identifies two effective RNA interference targets for D.citri control.展开更多
基金supported by Key Realm R&D Program of Guangdong Province (Grant No. 2020B0202090005)Special Fund for Scientific Innovation Strategy-construction of High Level Academy of Agriculture Science (Grant No. R2020PY-JG002)the President Foundation of Guangdong Academy of Agricultural Sciences (Grant No. 202030)。
文摘Huanglongbing(HLB) is a devastating disease that has led to an acute crisis for growers of citrus, one of the world's most important fruit crops. The phloem-feeding Asian citrus psyllid(ACP), Diaphorina citri, is the main pest at the new shoot stage and is the only natural vector of HLB pathogenic bacteria. Little is known about how plants perceive and defend themselves from this destructive pest. Here, we characterized changes in the expression of various genes in citrus plants that were continuously infested by D. citri for different durations(12, 24, and 48 h). A total of 5 219 differentially expressed genes(DEGs) and 643 common DEGs were identified across all time points. Several pathways related to defense were activated, such as peroxisome, alpha-linolenic acid metabolism, and phenylpropanoid and terpenoid biosynthesis, and some pathways related to growth and signal transduction were suppressed in response to D. citri infestation. The expression of genes including kinases(CML44, CIPK6, and XTH6), phytohormones(SAMT, LOX6, and NPR3), transcription factors(bHLH162, WRKY70, and WRKY40), and secondary metabolite synthesis-related genes(PAL, 4CL2, UGT74B1 and CYP82G1) was significantly altered in response to D. citri infestation. The findings of this study greatly enhance our understanding of the mechanisms underlying the defense response of citrus plants to D. citri infestation at the molecular level. Functional characterization of the candidate defense-related genes identified in this study will aid the molecular breeding of insect-resistant citrus varieties.
基金Supported by Science and Technology Major Project of Guangxi Province(GK AA20108003,GK AA22036002)Science and Technology Major Project of Nanning City(20212141)+6 种基金Collaborative Innovation Project of Chinese Academy of Agricultural Sciences-Guangxi Academy of Agricultural Sciences(CAAS-GXAAS-XTCX2019026-2)Guangxi Special Crops Experimental Station(G TS202201)Wuming District Science and Technology Project of Nanning City(2210201)Jiangnan District Science and Technology Project of Nanning City(2020020102)GNK(2021YT051,2022JM32)Guangxi Citrus Huanglongbing Prevention and Control Engineering Technology Research Center"Cultivation and Pest Control"Post Expert of Guangxi Citrus Innovation Team(nycytxgxcxtd-2021-05-02)。
文摘In order to promote the healthy and sustainable development of citrus industry in Guangxi and reduce the harm of Diaphorina citri and citrus Huanglongbing on citrus industry,the paper summarizes the occurrence of D.citri in Guangxi,and put forward comprehensive control technique,so as to provide the reference for guiding prevention and control of major pests in citrus industry.
基金supported by the Guangdong Laboratory of Lingnan Modern Agriculture Project(NT2021003)Natural Science Foundation of Guangdong Province(2019A1515011062)+3 种基金NSFC-Guangdong Joint Research Fund(U1701231)the National High Level Talent Special Support Plan(2020)the Earmarked Fund for Guangdong Modern Agro-Industry Technology Research System(2022KJ108)Study on Control Technology of Huanglongbing(KY-2017-001).
文摘Diaphorina citri is an important vector of Citrus Huanglongbing(HLB)disease.After feeding on young host plant shoots,the population of D.citri can increase significantly.Females also only lay eggs on young shoots.However,there are few studies on the mechanism of this phenomenon.Exogenous nutrient signals can affect the insulin signaling system of D.citri after feeding on young shoots.In this study,the expression of upstreamfactors DclLPl,DclLP2,and DclR in the insulin signaling system of D.citri was upregulated after feeding on young shoots.After being silenced by RNA interference technology,the results showed that the number of oviposited eggs of D.citri was significantly decreased and the ovarian development was inhibited with severe vacuolation.In addition,detection using quantitative reverse transcription-polymerase chain reaction showed that the upstream regulatory gene DcRheb of the target of rapamycin(TOR)pathway and the downstream reproduction-related DcVg gene were also significantly downregulated.These results suggest that feeding upon young shoots may upregulate the expression levels of upstream factors DclLPl,DclLP2,and DclR in the insulin signaling system.The signal will be through upregulating the expression of DcRheb,an upstream gene of the TOR signaling pathway.This in turn influences yolk metabolism,which eventually causes the ovaries of female D.citri to mature and therefore initiate oviposition behavior.
基金supported by the National Joint Fund for Regional Innovation and Development(U22A20481)the Laboratory of Lingnan Modern Agriculture Project(NT2021003)the National High-Level Talent Special Support Plan(2020)to BLQ and China Postdoctoral Science Foundation(No.2022M711208)to CFG。
文摘The Asian citrus psyllid,Diaphorina citri Kuwayama,is among the most im-portant pests of citrus.It is the main vector of the Huanglongbing(HLB)pathogen Can-didatus Liberibacter asiaticus(CLas),which causes severe losses in citrus crops.Control of D.citri is therefore of paramount importance to reduce the spread of HLB.In this re-gard,using RNA interference(RNAi)to silence target genes is a useful strategy to control psyllids.In this study,using RNAi,we examined the biological functions of the V-ATPase subunit E(V-ATP-E)gene of D.citri,including its effect on acquisition of CLas.The amino acid sequence of V-ATP-E from D.citri had high homology with proteins from other insects.V-ATP-E was expressed at all D.citri life stages analyzed,and the expres-sion level in mature adults was higher than that of teneral adults.Silencing of V-ATP-E resulted in a significant increase in mortality,reduced body weight,and induced cell apop-tosis of the D.citri midgut.The reduced expression of V-ATP-E was indicated to inhibit CLas passing through the midgut and into the hemolymph,leading to a majority of CLas being confined to the midgut.In addition,double-stranded RNA of D.citri V-ATP-E was safe to non-target parasitic wasps.These results suggest that V-ATP-E is an effective RNAi target that can be used in D.citri control to block CLas infection.
基金the National Natural Science Foundation of China(31960116)the Educational Commission of Jiangxi Province of China(GJJ180747)+1 种基金the National Key Research and Development Program of China(2018YFD0201504,the earmarked fund for Jiangxi Agriculture Research System(JXARS-07)Key Research and Development Plan of Jiangxi Province(20192BBF60057).
文摘The Asian citrus psyllid,Diaphorina citri is the principal vector of huanglongbing,which transmits Candidatus Liberibacter asiaticus.Trehalase is a key enzyme involved in trehalose hydrolysis and plays an important role in insect growth and development.The specific functions of this enzyme in D.citri have not been determined.In this study,three trehalase genes(DcTreJ-1,DcTrel-2,and DcTre2)were identified based on the D.citri genome database.Bioinformatic analysis showed that DcTrel-1 and DcTrel-2 are related to soluble trehalase,whereas DcTre2 is associated with membrane-bound trehalase.Spatiotemporal expression analysis indicated that DcTrel-1 and DcTrel-2 had the highest expression levels in the head and wing,respectively,and DcTre2 had high expression levels in the fat body.Furthermore,DcTrel-1 and DcTrel-2 expression levels were induced by 20-hydroxyecdysone and juvenile hormone III,but DcTre2 was unaffected.The expression levels of DcTrel-1,DcTrel-2,and DcTre2 were significantly up-regulated,which resulted in high mortality after treatment with validamycin.Trehalase activities and glucose contents were downregulated,but the trehalose content increased after treatment with validamycin.In addition,the expression levels of chitin metabolism-related genes significantly decreased at 24 and 48 h after treatment with validamycin.Furthermore,silencing of DcTrel-1,DcTrel-2,and DcTre2 reduced the expression levels of chitin metabolism-related genes and led to a malformed phenotype of D.citri.These results indicate that D.citri trehalase plays an essential role in regulating chitin metabolism and provides a new target for control of D.citri.
基金the Citrus Research Board(Grant#5500-222)for funding.
文摘The Asian citrus psyllid,Diaphorina citri,is the vector of the pathogenic bacteria that causes Huanglongbing,the most devasting disease affecting citrus worldwide.As cultivation of citrus tends to expand northward,the tolerance of psyllids to freezing temperatures needs to be investigated.While mortality of D.citri to cold temperature has been previously studied,much less is known regarding the acclimation potential of psyllids to cold temperatures.We first evaluated cold resistance of D.citri depending on color morph and sex.Subsequently,we compared mortality of D.citri at−4°C for 10 hours between unacclimated psyllids,psyllids that were gradually acclimated to cold over 1 or 2 weeks,and psyllids intermittently acclimated also for 1 or 2 weeks.We did not find major differences in cold resistance between color morphs and sex.We found that after 1 week of gradual acclimation,the survival of psyllids at−4°C increased to 86%,compared to 20%in the control group.Survival did not increase after the second week of gradual acclimation.Although intermittent acclimation improved survival compared to the control group,it was less effective than gradual acclimation with a survival at 30%and 70%after 1 and 2 weeks of acclimation,respectively,although this difference with gradual acclimation was not significant at week 2.These data show that gradual cold acclimation allows D.citri to survive brief periods below freezing.It may serve as a mechanism responsible for increasing northern establishment of this pest.
基金supported by the Natural Science Foundation of Jiangxi Province(20202BAB215004)the National Natural Science Foundation of China(31960116)+5 种基金the Educational Commission of Jiangxi Province of China(GJJ180747)Key Research and Development Plan of Jiangxi Province(20192BBF60057,2017ZDD02005)Ministry of Science and Technology of China(2018YFD0201504)the earmarked fund for Jiangxi Agriculture Research System(JXARS-07)Gan-nan Normal University-level bidding project(20162B08)Graduate student innovation Fund Project(YC2019-S392).
文摘Validamycin has been widely used as a specific competitive inhibitor of tre-halase.In our previous research,validamycin significantly inhibited trehalase activity and chitin synthesis in Diaphorina citri,resulting in abnormal phenotypes.However,the mechanism of validamycin's action on D.citri remains unclear.Here,using a comparative transcriptome analysis,464 differentially expressed genes(DEGs)in D.citri were identified after validamycin treatment.A Gene Ontology enrichment analysis revealed that these DEGs were mainly involved in“small molecule process”,“structural molecule ac-tivity”and“transition metal ion binding”.DEGs involved in chitin metabolism,cuticle synthesis and insecticide detoxification were validated by reverse transcription quantitative polymerase chain reaction.The RNA interference of D.citri chitinase-like protein EN03 and D.citri cuticle protein 7 genes significantly affected D.citri molting.Moreover,the recombinant chitinase-like protein EN03 exhibited a chitin-binding property,and an antimicrobial activity against Bacillus subtilis.This study provides a first insight into the molecular changes in D.citri after exposure to validamycin and identifies two effective RNA interference targets for D.citri control.
