Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signalin...Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signaling pathways plays a key role in the flower and fruit shedding.Hormones,peptides,carbohydrates,polyamines or cell wall modifying proteins regulate flower and fruit shedding.This article reviewed the recent studies of flower and fruit abscission,including the molecular regulation mechanism of abscission zone formation,typical structure and location of abscission zones,and other factors affecting flower and fruit abscission,such as stresses,hormones,peptides,carbohydrates,polyamines and cell wall modifying proteins.Overall,the review summarizes the developmental mechanism and the diversity of abscission zones,and the key factors affecting flower and fruit abscission of horticultural plants,aiming to provide guidance for studying the molecular regulatory mechanism of flower and fruit abscission.展开更多
Pecan is the only native north American tree nut.The USA produces approximately 80%of the world’s pecans.Pecan trees have an extended juvenility,10 years to the first nut crop.With mature bearing they begin alternate...Pecan is the only native north American tree nut.The USA produces approximately 80%of the world’s pecans.Pecan trees have an extended juvenility,10 years to the first nut crop.With mature bearing they begin alternate bearing;alternating large and small crops.Theoretically,a heavy crop inhibits flower induction in the current year resulting in a low crop the following year.The flowering of perennial trees involves a complex interplay of multiple hormones.The possible molecular mechanisms regulating tree flowering can be revealed by endogenous plant hormone quantification,exogenous hormone application and RNA-sequencing.In this review,we synthesize the investigations of transcriptomic analysis and exogenous hormone treatments on bud break and flowering in fruit/nut trees with a focus on pecan.Knowledge of how hormones regulate flowering suggest they are a potential tool for improving return bloom and mitigating alternate bearing.展开更多
Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the d...Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the disease.Commercial citrus varieties are highly susceptible to HLB,whereas trifoliate orange(Poncirus trifoliata)is considered highly tolerant to HLB.An F1 segregating population and their parent trifoliate orange and sweet orange,which had been exposed to intense HLB pressure for three years,was evaluated for disease symptoms,ACP colonization,C Las titer and tree vigor repeatedly for two to three years.Trifoliate orange and sweet orange showed significant differences for most of the phenotypic traits,and the F1 population exhibited a large variation.A high-density SNP-based genetic map with 1402 markers was constructed for trifoliate orange,which exhibited high synteny and high coverage of its reference genome.A total of 26 quantitative trait locus(QTLs)were identified in four linkage groups LG-t6,LG-t7,LG-t8 and LG-t9,of which four QTL clusters exhibit a clear co-localization of QTLs associated with different traits.Through genome-wide analysis of gene expression in response to C Las infection in‘Flying Dragon’and‘Larger-Flower DPI-50-7’trifoliate orange,85 differentially expressed genes were found located within the QTL clusters.Among them,seven genes were classified as defense or immunity protein which exhibited the highest transcriptional change after C Las infection.Our results indicate a quantitative genetic nature of HLB tolerance and identified candidate genes that should be valuable for searching for genetic solutions to HLB through breeding or genetic engineering.展开更多
Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor....Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor. Here, we constructed an Agrobacterium tumefaciensmediated transformation for generation of marker-free transgenic plants from navel orange(Citrus sinensis Osbeck) mature stems using a CreloxP recombination system. To efficiently recover the regenerated buds from mature tissues, five recovery methods were compared: in vitro micrografting of 0.1-0.5(1-2 weeks), > 0.5 cm(3-4 weeks) and > 1 cm long lignified bud and in vitro micrografting of explants with a bud and rooting regenerated bud. The data showed that in vitro micrografting of > 1 cm long regenerated bud with expanded leaves after one month of continuous culture for lignification was the optimal solution for plant recovery from mature tissues. Transgenic plants without selectable marker genes were created from navel orange(Citrus sinensis Osbeck) tissue using a transformation vector PLI-35SPR1aCB containing a Cre/loxP system recombination together with genes encoding the selectable marker isopentenyl transferase(IPT) and an anti-bacterial peptide(PR1aCB).Using IPT positive selection, the transformation efficiency determined by PCR was 0.9%, and in total, 20 transgenic plants were obtained.Southern blotting confirmed further their transgenicity. PCR and sequencing analysis demonstrated that both the Cre and IPT genes had been successfully removed from the transgenic plants(deletion efficiency 100%). Over all, using Cre/loxP system recombination together with the IPT positive selection, marker-free transgenic plants can be recovered efficiently from mature tissues of navel orange(Citrus sinensis Osbeck), which provides a potential method for production of transgenic plants from citrus mature tissue.展开更多
Citrus bacterial canker(CBC)results from Xanthomonas citri subsp.citri(Xcc)infection and poses a grave threat to citrus production.Class III peroxidases(CIII Prxs)are key proteins to the environmental adaptation of ci...Citrus bacterial canker(CBC)results from Xanthomonas citri subsp.citri(Xcc)infection and poses a grave threat to citrus production.Class III peroxidases(CIII Prxs)are key proteins to the environmental adaptation of citrus plants to a range of exogenous pathogens,but the role of CIII Prxs during plant resistance to CBC is poorly defined.Herein,we explored the role of CsPrx25 and its contribution to plant defenses in molecular detail.Based on the expression analysis,CsPrx25 was identified as an apoplast-localized protein that is differentially regulated by Xcc infection,salicylic acid,and methyl jasmone acid in the CBC-susceptible variety Wanjincheng(C.sinensis)and the CBC-resistant variety Calamondin(C.madurensis).Transgenic Wanjincheng plants overexpressing CsPrx25 were generated,and these transgenic plants exhibited significantly increased CBC resistance compared with the WT plants.In addition,the CsPrx25-overexpressing plants displayed altered reactive oxygen species(ROS)homeostasis accompanied by enhanced H_(2)O_(2) levels,which led to stronger hypersensitivity responses during Xcc infection.Moreover,the overexpression of CsPrx25 enhanced lignification as an apoplastic barrier for Xcc infection.Taken together,the results highlight how CsPrx25-mediated ROS homeostasis reconstruction and cell wall lignification can enhance the resistance of sweet orange to CBC.展开更多
Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,...Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,we identi fi ed an R2R3-MYB transcription factor,SlMYB72,that plays an important role in chlorophyll and carotenoid metabolism in tomato fruit.Here,we demonstrated that the SlMYB72-interacting protein SlZHD17,which belongs to the zinc-fi nger homeodomain transcription factor family,also functions in chlorophyll and carotenoid metabolism.Silencing SIZHD 17 in tomato improved multiple bene fi cial agronomic traits,including dwar fi sm,accelerated fl owering,and earlier fruit harvest.More importantly,downregulating SIZHD17 in fruits resulted in larger chloroplasts and a higher chlorophyll content.Dual-luciferase,yeast one-hybrid and electrophoretic mobility shift assays clari fi ed that SlZHD17 regulates the chlorophyll biosynthesis gene SIPOR-B and chloroplast developmental regulator SITKN2 in a direct manner.Chlorophyll degradation and plastid transformation were also retarded after suppression of SIZHD17 in fruits,which was caused by the inhibition of SISGR1,a crucial factor in chlorophyll degradation.On the other hand,the expression of the carotenoid biosynthesis genes SIPSY1 and SIZISO was also suppressed and directly regulated by SlZHD17,which induced uneven pigmentation and decreased the lycopene content in fruits with SIZHD17 suppression at the ripe stage.Furthermore,the protein-protein interactions between SlZHD17 and other pigment regulators,including SlARF4,SlBEL11,and SlTAGL1,were also presented.This study provides new insight into the complex pigment regulatory network and provides new options for breeding strategies aiming to improve fruit quality.展开更多
Mescaline,among the earliest identified natural hallucinogens,holds great potential in psychotherapy treatment.Nonetheless,despite the existence of a postulated biosynthetic pathway for more than half a century,the sp...Mescaline,among the earliest identified natural hallucinogens,holds great potential in psychotherapy treatment.Nonetheless,despite the existence of a postulated biosynthetic pathway for more than half a century,the specific enzymes involved in this process are yet to be identified.In this study,we investigated the cactus Lophophora williamsii(Peyote),the largest known natural producer of the phenethylamine mescaline.We employed a multi-faceted approach,combining de novo whole-genome and transcriptome sequencing with comprehensive chemical profiling,enzymatic assays,molecular modeling,and pathway engineering for pathway elucidation.We identified four groups of enzymes responsible for the six catalytic steps in the mescaline biosynthetic pathway,and an N-methyltransferase enzyme that N-methylates all phenethylamine intermediates,likely modulating mescaline levels in Peyote.Finally,we reconstructed the mescaline biosynthetic pathway in both Nicotiana benthamiana plants and yeast cells,providing novel insights into several challenges hindering complete heterologous mescaline production.Taken together,our study opens up avenues for exploration of sustainable production approaches and responsible utilization of mescaline,safeguarding this valuable natural resource for future generations.展开更多
Citrus is one of the most important commercial fruit crops worldwide.With the vast genomic data currently available for citrus fruit,genetic relationships,and molecular markers can be assessed for the development of m...Citrus is one of the most important commercial fruit crops worldwide.With the vast genomic data currently available for citrus fruit,genetic relationships,and molecular markers can be assessed for the development of molecular breeding and genomic selection strategies.In this study,to permit the ease of access to these data,a web-based database,the citrus genomic variation database(CitGVD,http://citgvd.cric.cn/home)was developed as the first citrusspecific comprehensive database dedicated to genome-wide variations including single nucleotide polymorphisms(SNPs)and insertions/deletions(INDELs).The current version(V1.0.0)of CitGVD is an open-access resource centered on 1,493,258,964 high-quality genomic variations and 84 phenotypes of 346 organisms curated from in-house projects and public resources.CitGVD integrates closely related information on genomic variation annotations,related gene annotations,and details regarding the organisms,incorporating a variety of built-in tools for data accession and analysis.As an example,CitGWAS can be used for genome-wide association studies(GWASs)with SNPs and phenotypic data,while CitEVOL can be used for genetic structure analysis.These features make CitGVD a comprehensive web portal and bioinformatics platform for citrus-related studies.It also provides a model for analyzing genome-wide variations for a wide range of crop varieties.展开更多
Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibit...Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibits transcriptional activator activity.Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants,whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type(WT)plants.Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants.Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars,whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits.RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism,photosynthesis and sugar metabolism.SlARF6A directly bound to the promoters of SlGLK1,CAB,and RbcS genes and positively regulated the expression of these genes.Overexpression of SlARF6A also inhibited fruit ripening and ethylene production,whereas downregulation of SlARF6A increased fruit ripening and ethylene production.SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression.Taken together,these results expand our understanding of ARFs with regard to photosynthesis,sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops.展开更多
The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in ...The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in the pollen and tapetum of tomato f lowers.Downregulation of SlMYB72 led to a decrease in the amounts of seeds due to abnormal pollen development compared with wild-type plants.Downregulation of SlMYB72 delayed tapetum degradation and inhibited autophagy in tomato anther.Overexpression of SlMYB72 led to abnormal pollen development and delayed tapetum degradation.Expression levels of some autophagy-related genes(ATGs)were decreased in SlMYB72 downregulated plants and increased in overexpression plants.SlMYB72 was directly bound to ACCAAC/ACCAAA motif of the SlATG7 promoter and activated its expression.Downregulation of SlATG7 inhibited the autophagy process and tapetum degradation,resulting in abnormal pollen development in tomatoes.These results indicated SlMYB72 affects the tapetum degradation and pollen development by transcriptional activation of SlATG7 and autophagy in tomato anther.The study expands the understanding of the regulation of autophagy by SlMYB72,uncovers the critical role that autophagy plays in pollen development,and provides potential candidate genes for the production of male-sterility in plants.展开更多
The RIPENING-INHIBITOR(RIN)transcriptional factor is a key regulator governing fruit ripening.While RIN also affects other physiological processes,its potential roles in triggering interactions with the rhizosphere mi...The RIPENING-INHIBITOR(RIN)transcriptional factor is a key regulator governing fruit ripening.While RIN also affects other physiological processes,its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown.Here we show that RIN affects microbiome-mediated disease resistance via root exudation,leading to recruitment of microbiota that suppress the soil-borne,phytopathogenic Ralstonia solanacearum bacterium.Compared with the wild-type(WT)plant,RIN mutants had different root exudate profiles,which were associated with distinct changes in microbiome composition and diversity.Specifically,the relative abundances of antibiosis-associated genes and pathogensuppressing Actinobacteria(Streptomyces)were clearly lower in the rhizosphere of rin mutants.The composition,diversity,and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin,which were exuded in much lower concentrations by the rin mutant.Interestingly,RIN-mediated effects on root exudates,Actinobacteria,and disease suppression were evident from the seedling stage,indicating that RIN plays a dual role in the early assembly of diseasesuppressive microbiota and late fruit development.Collectively,our work suggests that,while plant disease resistance is a complex trait driven by interactions between the plant,rhizosphere microbiome,and the pathogen,it can be indirectly manipulated using"prebiotic"compounds that promote the recruitment of disease-suppressive microbiota.展开更多
Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is d...Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is difficult.Here,we show that overexpression of the single gene SlMYB75(SlMYB75-OE)is effective at improving multiple fruit quality traits.In these engineered fruits,the anthocyanin content reached 1.86mg g−1 fresh weight at the red-ripe stage,and these SlMYB75-OE tomatoes displayed a series of physiological changes,including delayed ripening and increased ethylene production.In addition to anthocyanin,the total contents of phenolics,flavonoids and soluble solids in SlMYB75-OE fruits were enhanced by 2.6,4,and 1.2 times,respectively,compared to those of wild-type(WT)fruits.Interestingly,a number of aroma volatiles,such as aldehyde,phenylpropanoid-derived and terpene volatiles,were significantly increased in SlMYB75-OE fruits,with some terpene volatiles showing more than 10 times higher levels than those in WT fruits.Consistent with the metabolic assessment,transcriptomic profiling indicated that the genes involved in the ethylene signaling,phenylpropanoid and isoprenoid pathways were greatly upregulated in SlMYB75-OE fruits.Yeast one-hybrid and transactivation assays revealed that SlMYB75 is able to directly bind to the MYBPLANT and MYBPZM cis-regulatory elements and to activate the promoters of the LOXC,AADC2 and TPS genes.The identification of SlMYB75 as a key regulator of fruit quality attributes through the transcriptional regulation of downstream genes involved in several metabolic pathways opens new avenues towards engineering fruits with a higher sensory and nutritional quality.展开更多
GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcripti...GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear.Here,we demonstrated that SlGRAS4,encoding a transcription factor of the GRAS family,was induced by the tomato ripening process and regulated by ethylene.Overexpression of SlGRAS4 accelerated fruit ripening,increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit.The expression levels of key ethylene biosynthesis genes(SlACS2,SlACS4,SlACO1,and SlACO3)and crucial ripening regulators(RIN and NOR)were increased in SlGRAS4-OE fruit.The negative regulator of tomato fruit ripening,SlMADS1,was repressed in OE fruit.Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit.More obvious phenotypes were observed in OE seedlings after ACC treatment.Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription,and SlGRAS4 can also directly repress SlMADS1 expression.Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner.This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.展开更多
Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of ...Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of waxy maize parental materials,S181 and 49B,created by the Chongqing Academy of Agricultural Sciences,are widely grown in China.S181 shows higher starch and sugar contents than 49B.This study generated metabolic profiles to assess the differences between the two varieties.A total of 674 metabolites that were significantly differentially expressed between the two varieties were identified by gas chromatography and untargeted metabolomics technology.These metabolites were associated with 21 categories,including antioxidant metabolites.Moreover,6415 differentially expressed genes(DEGs)were identified by RNA-seq.Interestingly,these DEGs comprised starch and sugar synthesis pathway genes and 72 different transcription factor families.Among these,six families that were reported to play an essential role in plant antioxidant action accounted for 39.2%of the transcription factor families.Using the Kyoto Encyclopedia of Genes and Genomes(KEGG)classification,the DEGs were mainly involved in amino acid biosynthesis,glycolysis/glucose metabolism,and the synthetic and metabolic pathways of antioxidant active substances.Furthermore,the correlation analysis of transcriptome and metabolomics identified five key transcription factors(ZmbHLH172,ZmNAC44,ZmNAC-like18,ZmS1FA2,ZmERF172),one ubiquitin ligase gene(ZmE25A)and one sucrose synthase gene(ZmSS1).They likely contribute to the quality traits of waxy corn through involvement in the metabolic regulatory network of antioxidant substances.Thus,our results provide new insights into maize quality-related antioxidant metabolite networks and have potential applications for waxy corn breeding.展开更多
The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In d...The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In different species,ERFs have been reported to be involved in plant development,flower abscission,fruit ripening,and defense responses.In this review,based on the new progress made by recent studies,we summarize the specific role and mode of action of ERFs in regulating different aspects of ripening in both climacteric and non-climacteric fruits,and provide new insights into the role of ethylene in non-climacteric fruit ripening.展开更多
Fruits are an essential part of a healthy,balanced diet and it is particularly important for fibre,essential vitamins,and trace elements.Improvement in the quality of fruit and elongation of shelf life are crucial goa...Fruits are an essential part of a healthy,balanced diet and it is particularly important for fibre,essential vitamins,and trace elements.Improvement in the quality of fruit and elongation of shelf life are crucial goals for researchers.However,traditional techniques have some drawbacks,such as long period,low efficiency,and difficulty in the modification of target genes,which limit the progress of the study.Recently,the clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technique was developed and has become the most popular gene-editing technology with high efficiency,simplicity,and low cost.CRISPR/Cas9 technique is widely accepted to analyse gene function and complete genetic modification.This review introduces the latest progress of CRISPR/Cas9 technology in fruit quality improvement.For example,CRISPR/Cas9-mediated targeted mutagenesis of RIPENING INHIBITOR gene(RIN),Lycopene desaturase(PDS),Pectate lyases(PL),SlMYB12,and CLAVATA3(CLV3)can affect fruit ripening,fruit bioactive compounds,fruit texture,fruit colouration,and fruit size.CRISPR/Cas9-mediated mutagenesis has become an efficient method to modify target genes and improve fruit quality.展开更多
基金funded by the National Natural Science Foundation of China(Grant Nos.31972470,32002100,31772370)Key research and development project of Sichuan Provincial Science and Technology Department(Grant No.2021YFQ0071)。
文摘Flower and fruit abscission is a highly programmed physiological process,which is closely related to the yield of horticultural plants.The coordination of many regulatory factors associated with metabolic and signaling pathways plays a key role in the flower and fruit shedding.Hormones,peptides,carbohydrates,polyamines or cell wall modifying proteins regulate flower and fruit shedding.This article reviewed the recent studies of flower and fruit abscission,including the molecular regulation mechanism of abscission zone formation,typical structure and location of abscission zones,and other factors affecting flower and fruit abscission,such as stresses,hormones,peptides,carbohydrates,polyamines and cell wall modifying proteins.Overall,the review summarizes the developmental mechanism and the diversity of abscission zones,and the key factors affecting flower and fruit abscission of horticultural plants,aiming to provide guidance for studying the molecular regulatory mechanism of flower and fruit abscission.
基金supported by Oklahoma Department of Agriculture,Food,&Forestry Specialty Crop Grant Program and Oklahoma Pecan Growers’Association.
文摘Pecan is the only native north American tree nut.The USA produces approximately 80%of the world’s pecans.Pecan trees have an extended juvenility,10 years to the first nut crop.With mature bearing they begin alternate bearing;alternating large and small crops.Theoretically,a heavy crop inhibits flower induction in the current year resulting in a low crop the following year.The flowering of perennial trees involves a complex interplay of multiple hormones.The possible molecular mechanisms regulating tree flowering can be revealed by endogenous plant hormone quantification,exogenous hormone application and RNA-sequencing.In this review,we synthesize the investigations of transcriptomic analysis and exogenous hormone treatments on bud break and flowering in fruit/nut trees with a focus on pecan.Knowledge of how hormones regulate flowering suggest they are a potential tool for improving return bloom and mitigating alternate bearing.
基金supported by grants from the Citrus Research and Development Foundation,USA(Grant No.CRDF#15-010)the New Varieties Development and Management Corporation(NVDMC),on behalf of the Florida citrus industry,USA,the Fundamental Research Funds for the Central Universities,China(Grant No.2022CDJXY-004)from the USDA-NIFA-SCRI,USA(Grant No.2015-70016-2302).
文摘Huanglongbing(HLB)is the most devastating disease for citrus worldwide.Candidatus Liberibacter asiaticus(C Las),vectored by Asian citrus psyllid(ACP,Diaphorina citri Kuwayama),is the most common pathogen causing the disease.Commercial citrus varieties are highly susceptible to HLB,whereas trifoliate orange(Poncirus trifoliata)is considered highly tolerant to HLB.An F1 segregating population and their parent trifoliate orange and sweet orange,which had been exposed to intense HLB pressure for three years,was evaluated for disease symptoms,ACP colonization,C Las titer and tree vigor repeatedly for two to three years.Trifoliate orange and sweet orange showed significant differences for most of the phenotypic traits,and the F1 population exhibited a large variation.A high-density SNP-based genetic map with 1402 markers was constructed for trifoliate orange,which exhibited high synteny and high coverage of its reference genome.A total of 26 quantitative trait locus(QTLs)were identified in four linkage groups LG-t6,LG-t7,LG-t8 and LG-t9,of which four QTL clusters exhibit a clear co-localization of QTLs associated with different traits.Through genome-wide analysis of gene expression in response to C Las infection in‘Flying Dragon’and‘Larger-Flower DPI-50-7’trifoliate orange,85 differentially expressed genes were found located within the QTL clusters.Among them,seven genes were classified as defense or immunity protein which exhibited the highest transcriptional change after C Las infection.Our results indicate a quantitative genetic nature of HLB tolerance and identified candidate genes that should be valuable for searching for genetic solutions to HLB through breeding or genetic engineering.
基金supported by the Fundamental Research Funds for the Central Universities (Grant No. XDJK 2018B016)the National Natural Sciences Foundation of China (Grant No. 31972393)+1 种基金he earmarked fund for China Agriculture Research System (Grant No. CARS-26)the Natural Science Foundation of Chongqing (Grant No. cstc2020jcyj-msxmX1064)。
文摘Genetic transformation with mature material as the explants could shorten the transgenic period and avoid seed dependence compared with genetic transformation using the epicotyl seedling stem segments as the receptor. Here, we constructed an Agrobacterium tumefaciensmediated transformation for generation of marker-free transgenic plants from navel orange(Citrus sinensis Osbeck) mature stems using a CreloxP recombination system. To efficiently recover the regenerated buds from mature tissues, five recovery methods were compared: in vitro micrografting of 0.1-0.5(1-2 weeks), > 0.5 cm(3-4 weeks) and > 1 cm long lignified bud and in vitro micrografting of explants with a bud and rooting regenerated bud. The data showed that in vitro micrografting of > 1 cm long regenerated bud with expanded leaves after one month of continuous culture for lignification was the optimal solution for plant recovery from mature tissues. Transgenic plants without selectable marker genes were created from navel orange(Citrus sinensis Osbeck) tissue using a transformation vector PLI-35SPR1aCB containing a Cre/loxP system recombination together with genes encoding the selectable marker isopentenyl transferase(IPT) and an anti-bacterial peptide(PR1aCB).Using IPT positive selection, the transformation efficiency determined by PCR was 0.9%, and in total, 20 transgenic plants were obtained.Southern blotting confirmed further their transgenicity. PCR and sequencing analysis demonstrated that both the Cre and IPT genes had been successfully removed from the transgenic plants(deletion efficiency 100%). Over all, using Cre/loxP system recombination together with the IPT positive selection, marker-free transgenic plants can be recovered efficiently from mature tissues of navel orange(Citrus sinensis Osbeck), which provides a potential method for production of transgenic plants from citrus mature tissue.
基金The National Key Research and Development Program of China(2018YFD1000306)the Natural Science Foundation of Chongqing(cstc2020jcyj-msxmX1064)+2 种基金the Fundamental Research Funds for the Central Universities(SWU115025)the Earmarked Funds for the China Agriculture Research System(CARS-26)the Key Project of Guangxi Science and Technology(GuiKeAA18118046-6)funded this study.
文摘Citrus bacterial canker(CBC)results from Xanthomonas citri subsp.citri(Xcc)infection and poses a grave threat to citrus production.Class III peroxidases(CIII Prxs)are key proteins to the environmental adaptation of citrus plants to a range of exogenous pathogens,but the role of CIII Prxs during plant resistance to CBC is poorly defined.Herein,we explored the role of CsPrx25 and its contribution to plant defenses in molecular detail.Based on the expression analysis,CsPrx25 was identified as an apoplast-localized protein that is differentially regulated by Xcc infection,salicylic acid,and methyl jasmone acid in the CBC-susceptible variety Wanjincheng(C.sinensis)and the CBC-resistant variety Calamondin(C.madurensis).Transgenic Wanjincheng plants overexpressing CsPrx25 were generated,and these transgenic plants exhibited significantly increased CBC resistance compared with the WT plants.In addition,the CsPrx25-overexpressing plants displayed altered reactive oxygen species(ROS)homeostasis accompanied by enhanced H_(2)O_(2) levels,which led to stronger hypersensitivity responses during Xcc infection.Moreover,the overexpression of CsPrx25 enhanced lignification as an apoplastic barrier for Xcc infection.Taken together,the results highlight how CsPrx25-mediated ROS homeostasis reconstruction and cell wall lignification can enhance the resistance of sweet orange to CBC.
基金This work was sponsored by the National Natural Science Foundation of China(No.32002100,31772370,31972470).
文摘Chlorophylls and carotenoids are essential and bene fi cial substances for both plant and human health.Identifying the regulatory network of these pigments is necessary for improving fruit quality.In a previous study,we identi fi ed an R2R3-MYB transcription factor,SlMYB72,that plays an important role in chlorophyll and carotenoid metabolism in tomato fruit.Here,we demonstrated that the SlMYB72-interacting protein SlZHD17,which belongs to the zinc-fi nger homeodomain transcription factor family,also functions in chlorophyll and carotenoid metabolism.Silencing SIZHD 17 in tomato improved multiple bene fi cial agronomic traits,including dwar fi sm,accelerated fl owering,and earlier fruit harvest.More importantly,downregulating SIZHD17 in fruits resulted in larger chloroplasts and a higher chlorophyll content.Dual-luciferase,yeast one-hybrid and electrophoretic mobility shift assays clari fi ed that SlZHD17 regulates the chlorophyll biosynthesis gene SIPOR-B and chloroplast developmental regulator SITKN2 in a direct manner.Chlorophyll degradation and plastid transformation were also retarded after suppression of SIZHD17 in fruits,which was caused by the inhibition of SISGR1,a crucial factor in chlorophyll degradation.On the other hand,the expression of the carotenoid biosynthesis genes SIPSY1 and SIZISO was also suppressed and directly regulated by SlZHD17,which induced uneven pigmentation and decreased the lycopene content in fruits with SIZHD17 suppression at the ripe stage.Furthermore,the protein-protein interactions between SlZHD17 and other pigment regulators,including SlARF4,SlBEL11,and SlTAGL1,were also presented.This study provides new insight into the complex pigment regulatory network and provides new options for breeding strategies aiming to improve fruit quality.
基金fellowships from the Israel Ministry of Absorption and the Dean of the Plant Science Department in the Weizmann Institute.We thank Prof.David Nelson(University of Tennessee,USA)for the systematic naming of the cytochrome P450 enzymes characterized in this studyShmuel Regev and The Regev Nursery(Beit Elazari,Israel)for help in differentiating among Lophophora species+2 种基金Dr.Ziv Spiegelman for providing several N.benthamiana plantsXINTEZA(https://xinteza.com/)for funding this researchand the Adelis Foundation,the Leona M.and Harry B.Helmsley Charitable Trust,the Jeanne and Joseph Nissim Foundation for Life Sciences,Tom and Sondra Rykoff Family Foundation Research,Ron Sklare and the Raymond Burton Plant Genome Research Fund for supporting the A.A.laboratory。
文摘Mescaline,among the earliest identified natural hallucinogens,holds great potential in psychotherapy treatment.Nonetheless,despite the existence of a postulated biosynthetic pathway for more than half a century,the specific enzymes involved in this process are yet to be identified.In this study,we investigated the cactus Lophophora williamsii(Peyote),the largest known natural producer of the phenethylamine mescaline.We employed a multi-faceted approach,combining de novo whole-genome and transcriptome sequencing with comprehensive chemical profiling,enzymatic assays,molecular modeling,and pathway engineering for pathway elucidation.We identified four groups of enzymes responsible for the six catalytic steps in the mescaline biosynthetic pathway,and an N-methyltransferase enzyme that N-methylates all phenethylamine intermediates,likely modulating mescaline levels in Peyote.Finally,we reconstructed the mescaline biosynthetic pathway in both Nicotiana benthamiana plants and yeast cells,providing novel insights into several challenges hindering complete heterologous mescaline production.Taken together,our study opens up avenues for exploration of sustainable production approaches and responsible utilization of mescaline,safeguarding this valuable natural resource for future generations.
基金funded by the National Key Research and Development Program of China(2018YFD1000306)Earmarked Funds for the China Agriculture Research System(CARS-26)the Guangxi Science and Technology Key Project(GuiKeAA18118046-6).
文摘Citrus is one of the most important commercial fruit crops worldwide.With the vast genomic data currently available for citrus fruit,genetic relationships,and molecular markers can be assessed for the development of molecular breeding and genomic selection strategies.In this study,to permit the ease of access to these data,a web-based database,the citrus genomic variation database(CitGVD,http://citgvd.cric.cn/home)was developed as the first citrusspecific comprehensive database dedicated to genome-wide variations including single nucleotide polymorphisms(SNPs)and insertions/deletions(INDELs).The current version(V1.0.0)of CitGVD is an open-access resource centered on 1,493,258,964 high-quality genomic variations and 84 phenotypes of 346 organisms curated from in-house projects and public resources.CitGVD integrates closely related information on genomic variation annotations,related gene annotations,and details regarding the organisms,incorporating a variety of built-in tools for data accession and analysis.As an example,CitGWAS can be used for genome-wide association studies(GWASs)with SNPs and phenotypic data,while CitEVOL can be used for genetic structure analysis.These features make CitGVD a comprehensive web portal and bioinformatics platform for citrus-related studies.It also provides a model for analyzing genome-wide variations for a wide range of crop varieties.
基金supported by the National Key R&D Program of China(2016YFD0400100)the Project of Chongqing Science and Technology Commission(CSTC2015JCYJA80018)the National Natural Science Foundation of China(31272165).
文摘Auxin response factors(ARFs)are involved in auxin-mediated transcriptional regulation in plants.In this study,we performed functional characterization of SlARF6A in tomato.SlARF6A is located in the nucleus and exhibits transcriptional activator activity.Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants,whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type(WT)plants.Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants.Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars,whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits.RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism,photosynthesis and sugar metabolism.SlARF6A directly bound to the promoters of SlGLK1,CAB,and RbcS genes and positively regulated the expression of these genes.Overexpression of SlARF6A also inhibited fruit ripening and ethylene production,whereas downregulation of SlARF6A increased fruit ripening and ethylene production.SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression.Taken together,these results expand our understanding of ARFs with regard to photosynthesis,sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops.
基金supported by the National Natural Science Foundation of China(32172596)the Technology Innovation and Application Development Project in Chongqing(cstc2021jscxcylhX0115)+3 种基金the Chongqing Talents Innovation Leading Talents Project(cstc2022ycjh-bgzxm0018)the Tianfu Scholar Program of Sichuan Province(Department of Human Resources and Social Security of Sichuan Province 2021-58)d the Fundamental Research Funds for the Central Universities(2021CDJZYJH002)The Graduate Research and Innovation Foundation of Chongqing,China(CYB22048).
文摘The formation and development of pollen are among the most critical processes for reproduction and genetic diversity in the life cycle of f lowering plants.The present study found that SlMYB72 was highly expressed in the pollen and tapetum of tomato f lowers.Downregulation of SlMYB72 led to a decrease in the amounts of seeds due to abnormal pollen development compared with wild-type plants.Downregulation of SlMYB72 delayed tapetum degradation and inhibited autophagy in tomato anther.Overexpression of SlMYB72 led to abnormal pollen development and delayed tapetum degradation.Expression levels of some autophagy-related genes(ATGs)were decreased in SlMYB72 downregulated plants and increased in overexpression plants.SlMYB72 was directly bound to ACCAAC/ACCAAA motif of the SlATG7 promoter and activated its expression.Downregulation of SlATG7 inhibited the autophagy process and tapetum degradation,resulting in abnormal pollen development in tomatoes.These results indicated SlMYB72 affects the tapetum degradation and pollen development by transcriptional activation of SlATG7 and autophagy in tomato anther.The study expands the understanding of the regulation of autophagy by SlMYB72,uncovers the critical role that autophagy plays in pollen development,and provides potential candidate genes for the production of male-sterility in plants.
基金the National Key Research and Development Program of China(2021YFD1900100,2022YFD1500202,and 2022YFF1001804)the Fundamental Research Funds for the Central Universities(KYT2023001)+1 种基金the National Natural Science Foundation of China(42325704,41922053,31972504,and 42377118)V.P.F.is funded by the Royal Society(RSG\R1\180213 and CHL\R1\180031)and jointly by a grant from UKRI,Defra,and the Scottish Government,under the Strategic Priorities Fund Plant Bacterial Diseases program(BB/T010606/1)at the University of York.
文摘The RIPENING-INHIBITOR(RIN)transcriptional factor is a key regulator governing fruit ripening.While RIN also affects other physiological processes,its potential roles in triggering interactions with the rhizosphere microbiome and plant health are unknown.Here we show that RIN affects microbiome-mediated disease resistance via root exudation,leading to recruitment of microbiota that suppress the soil-borne,phytopathogenic Ralstonia solanacearum bacterium.Compared with the wild-type(WT)plant,RIN mutants had different root exudate profiles,which were associated with distinct changes in microbiome composition and diversity.Specifically,the relative abundances of antibiosis-associated genes and pathogensuppressing Actinobacteria(Streptomyces)were clearly lower in the rhizosphere of rin mutants.The composition,diversity,and suppressiveness of rin plant microbiomes could be restored by the application of 3-hydroxyflavone and riboflavin,which were exuded in much lower concentrations by the rin mutant.Interestingly,RIN-mediated effects on root exudates,Actinobacteria,and disease suppression were evident from the seedling stage,indicating that RIN plays a dual role in the early assembly of diseasesuppressive microbiota and late fruit development.Collectively,our work suggests that,while plant disease resistance is a complex trait driven by interactions between the plant,rhizosphere microbiome,and the pathogen,it can be indirectly manipulated using"prebiotic"compounds that promote the recruitment of disease-suppressive microbiota.
基金supported by the National Key Research and Development Program(2016YFD0400101)the National Natural Science Foundation of China(31572175,31772370)+1 种基金the Fundamental Research Funds for the Central Universities(2018CDXYSM0021)the Committee of Science and Technology of Chongqing(cstckjcxljrc15).
文摘Genetic manipulation of genes to upregulate specific branches of metabolic pathways is a method that is commonly used to improve fruit quality.However,the use of a single gene to impact several metabolic pathways is difficult.Here,we show that overexpression of the single gene SlMYB75(SlMYB75-OE)is effective at improving multiple fruit quality traits.In these engineered fruits,the anthocyanin content reached 1.86mg g−1 fresh weight at the red-ripe stage,and these SlMYB75-OE tomatoes displayed a series of physiological changes,including delayed ripening and increased ethylene production.In addition to anthocyanin,the total contents of phenolics,flavonoids and soluble solids in SlMYB75-OE fruits were enhanced by 2.6,4,and 1.2 times,respectively,compared to those of wild-type(WT)fruits.Interestingly,a number of aroma volatiles,such as aldehyde,phenylpropanoid-derived and terpene volatiles,were significantly increased in SlMYB75-OE fruits,with some terpene volatiles showing more than 10 times higher levels than those in WT fruits.Consistent with the metabolic assessment,transcriptomic profiling indicated that the genes involved in the ethylene signaling,phenylpropanoid and isoprenoid pathways were greatly upregulated in SlMYB75-OE fruits.Yeast one-hybrid and transactivation assays revealed that SlMYB75 is able to directly bind to the MYBPLANT and MYBPZM cis-regulatory elements and to activate the promoters of the LOXC,AADC2 and TPS genes.The identification of SlMYB75 as a key regulator of fruit quality attributes through the transcriptional regulation of downstream genes involved in several metabolic pathways opens new avenues towards engineering fruits with a higher sensory and nutritional quality.
基金the Natural Science Foundation of Chongqing,China(cstc2019jcyj-bshX0008 to Y.L.)funding provided by the National Key Research and Development Program(2016YFD0400101)the National Natural Science Foundation of China(No.31772370,31972470)to Z.L.
文摘GRAS proteins are plant-specific transcription factors that play crucial roles in plant development and stress responses.However,their involvement in the ripening of economically important fruits and their transcriptional regulatory mechanisms remain largely unclear.Here,we demonstrated that SlGRAS4,encoding a transcription factor of the GRAS family,was induced by the tomato ripening process and regulated by ethylene.Overexpression of SlGRAS4 accelerated fruit ripening,increased the total carotenoid content and increased PSY1 expression in SlGRAS4-OE fruit compared to wild-type fruit.The expression levels of key ethylene biosynthesis genes(SlACS2,SlACS4,SlACO1,and SlACO3)and crucial ripening regulators(RIN and NOR)were increased in SlGRAS4-OE fruit.The negative regulator of tomato fruit ripening,SlMADS1,was repressed in OE fruit.Exogenous ethylene and 1-MCP treatment revealed that more endogenous ethylene was derived in SlGRAS4-OE fruit.More obvious phenotypes were observed in OE seedlings after ACC treatment.Yeast one-hybrid and dual-luciferase assays confirmed that SlGRAS4 can directly bind SlACO1 and SlACO3 promoters to activate their transcription,and SlGRAS4 can also directly repress SlMADS1 expression.Our study identified that SlGRAS4 acts as a new regulator of fruit ripening by regulating ethylene biosynthesis genes in a direct manner.This provides new knowledge of GRAS transcription factors involved in regulating fruit ripening.
基金supported by the General Program of Natural Science Foundation of Chongqing(cstc2019jcyj msxmx0468)Chongqing Talents Program—Basic Research and Frontier Exploration(cstc2021ycjh bgzxm0152)+1 种基金Chongqing Agricultural Development Fund Project—Resource Plant New Variety Breeding and Application(NKY-2020AB015)the Fundamental Research Funds for the Central Universities(2022CDJXY-004),China.
文摘Maize is an essential source of nutrition for humans and animals and is rich in various metabolites that determine its quality.Different maize varieties show significant differences in metabolite content.Two kinds of waxy maize parental materials,S181 and 49B,created by the Chongqing Academy of Agricultural Sciences,are widely grown in China.S181 shows higher starch and sugar contents than 49B.This study generated metabolic profiles to assess the differences between the two varieties.A total of 674 metabolites that were significantly differentially expressed between the two varieties were identified by gas chromatography and untargeted metabolomics technology.These metabolites were associated with 21 categories,including antioxidant metabolites.Moreover,6415 differentially expressed genes(DEGs)were identified by RNA-seq.Interestingly,these DEGs comprised starch and sugar synthesis pathway genes and 72 different transcription factor families.Among these,six families that were reported to play an essential role in plant antioxidant action accounted for 39.2%of the transcription factor families.Using the Kyoto Encyclopedia of Genes and Genomes(KEGG)classification,the DEGs were mainly involved in amino acid biosynthesis,glycolysis/glucose metabolism,and the synthetic and metabolic pathways of antioxidant active substances.Furthermore,the correlation analysis of transcriptome and metabolomics identified five key transcription factors(ZmbHLH172,ZmNAC44,ZmNAC-like18,ZmS1FA2,ZmERF172),one ubiquitin ligase gene(ZmE25A)and one sucrose synthase gene(ZmSS1).They likely contribute to the quality traits of waxy corn through involvement in the metabolic regulatory network of antioxidant substances.Thus,our results provide new insights into maize quality-related antioxidant metabolite networks and have potential applications for waxy corn breeding.
基金This research was supported by the National Key R&D Program of China(2016YFD0400100)the National Natural Science Foundation of China(31772372).
文摘The ethylene response factors(ERFs)belong to the APETALA2/ethylene response factor(AP2/ERF)superfamily and act downstream of the ethylene signalling pathway to regulate the expression of ethylene responsive genes.In different species,ERFs have been reported to be involved in plant development,flower abscission,fruit ripening,and defense responses.In this review,based on the new progress made by recent studies,we summarize the specific role and mode of action of ERFs in regulating different aspects of ripening in both climacteric and non-climacteric fruits,and provide new insights into the role of ethylene in non-climacteric fruit ripening.
基金The research was supported by the National Natural Science Foundation of China(31960618)the National Key Research and Development Program(2016YFD0400100),China.
文摘Fruits are an essential part of a healthy,balanced diet and it is particularly important for fibre,essential vitamins,and trace elements.Improvement in the quality of fruit and elongation of shelf life are crucial goals for researchers.However,traditional techniques have some drawbacks,such as long period,low efficiency,and difficulty in the modification of target genes,which limit the progress of the study.Recently,the clustered regularly interspaced short palindromic repeats(CRISPR)/Cas9 technique was developed and has become the most popular gene-editing technology with high efficiency,simplicity,and low cost.CRISPR/Cas9 technique is widely accepted to analyse gene function and complete genetic modification.This review introduces the latest progress of CRISPR/Cas9 technology in fruit quality improvement.For example,CRISPR/Cas9-mediated targeted mutagenesis of RIPENING INHIBITOR gene(RIN),Lycopene desaturase(PDS),Pectate lyases(PL),SlMYB12,and CLAVATA3(CLV3)can affect fruit ripening,fruit bioactive compounds,fruit texture,fruit colouration,and fruit size.CRISPR/Cas9-mediated mutagenesis has become an efficient method to modify target genes and improve fruit quality.
