Starch degradation in cells is closely associated with cereal seed germination, photosynthesis in leaves, carbohydrate storage in tuber and tuberous roots, and fleshy fruit development. Based on previously reported ...Starch degradation in cells is closely associated with cereal seed germination, photosynthesis in leaves, carbohydrate storage in tuber and tuberous roots, and fleshy fruit development. Based on previously reported in vitro assays, β amylase is considered as one of the key enzymes catalyzing starch breakdown, but up to date its role in starch breakdown in living cells remains unclear because the enzyme was shown often extrachloroplastic in living cells. Recently we have shown for the first time that β_amylase is predominantly immuno_localized to plastids in living cells of developing apple fruit. But it remains to know whether this model of β_amylase compartmentation is more widespread in plant living cells. The present experiment, conducted in tuberous root of sweet potato ( Ipomea batatas Lam. cv. Xushu 18) and via immunogold electron_microscopy technique, showed that β amylase visualized by gold particles was predominantly localized in plastids especially at periphery of starch granules, but the gold particles were scarcely found in other subcellular compartments, indicating that the enzyme is subcellularly compartmented in the same zone as its starch substrates. The density of gold particles (β amylase) in plastids was increasing during growing season, but the predominantly plastid_distributed pattern of β amylase in cells was shown unchanged throughout the tuberous root development. These data prove that the enzyme is compartmented in its functional sites, and so provide evidence to support the possible widespread biological function of the enzyme in catalyzing starch breakdown in plant living cells or at least in living cells of plant storage organs.展开更多
AIM： To cost-effectively express the 23-ku pE2, the most promising subunit vaccine encoded by the E2 fragment comprising of the 3＇-portion of hepatitis E virus （HEV） open reading frame 2 （ORF2） in plastids of to...AIM： To cost-effectively express the 23-ku pE2, the most promising subunit vaccine encoded by the E2 fragment comprising of the 3＇-portion of hepatitis E virus （HEV） open reading frame 2 （ORF2） in plastids of tobacco （Nicotiana tabacum cv. SR1）, to investigate the transgene expression and pE2 accumulation in plastids, and to evaluate the antigenic effect of the plastid-derived pE2 in mice. METHODS： Plastid-targeting vector pRB94-E2 containing the E2 fragment driven by rice psbA promoter was constructed. Upon delivery into tobacco plastids, this construct could initiate homologous recombination in psaB-trnfM and trnG-psbC fragments in plastid genome, and result in transgene inserted between the two fragments. The pRB94-E2 was delivered with a biolistic particle bombardment method, and the plastid-transformed plants were obtained following the regeneration of the bombarded leaf tissues on a spectinomycin-supplemented medium. Transplastomic status of the regenerated plants was confirmed by PCR and Southern blot analysis, transgene expression was investigated by Northern blot analysis, and accumulation of pE2 was measured by ELISA. Furthermore, protein extracts were used to immunize mice, and the presence of the pE2-reactive antibodies in serum samples of the immunized mice was studied by ELISA. RESULTS： Transplastomic lines confirmed by PCR and Southern blot analysis could actively transcribe the E2 mRNA. The pE2 polypeptide was accumulated to a level as high as 13.27 μg/g fresh leaves. The pE2 could stimulate the immunized mice to generate pE2-specific antibodies. CONCLUSION： HEV-E2 fragment can be inserted into the plastid genome and the recombinant pE2 antigen derived is antigenic in mice. Hence, plastids may be a novel source for cost-effective production of HEV vaccines.展开更多
Mechanisms that allocate cellular space to organelles are of fundamental importance to biology but remain poorly understood.A detailed understanding of mechanisms that allocate cellular space to plastids,such as chlor...Mechanisms that allocate cellular space to organelles are of fundamental importance to biology but remain poorly understood.A detailed understanding of mechanisms that allocate cellular space to plastids,such as chloroplasts,will lead to high-yielding crops with enhanced nutritional value.The HIGH PIGMENT(HP)genes in tomato contribute to regulated proteolysis and abscisic acid metabolism.The HP1 gene was the first gene reported to influence the amount of cellular space occupied by chloroplasts and chromoplasts almost 20 years ago.Recently,our knowledge of mechanisms that allocate cellular space to plastids was enhanced by new information on the influence of cell type on the amount of cellular space occupied by plastids and the identification of new genes that help to allocate cellular space to plastids.These genes encode proteins with unknown and diverse biochemical functions.Several transcription factors were recently reported to regulate the numbers and sizes of chloroplasts in fleshy fruit.If these transcription factors do not induce compensating effects on cell size,they should affect the amount of cellular space occupied by plastids.Although we can now propose more detailed models for the network that allocates cellular space to plastids,many gaps remain in our knowledge of this network and the genes targeted by this network.Nonetheless,these recent breakthroughs provide optimism for future progress in this field.展开更多
Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoi...Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.展开更多
Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological...Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological processes,such as acting as accessory light-harvesting pigments in photosynthesis,participating in photoprotection,and serving as precursors for the hormones abscisic acid(ABA)and strigolactones(Ruiz-Sola and Rodriguez-Concepcion,2012).展开更多
Male gametes are produced in the anthers and are essential for fertilization and seed setting.A transverse section of the anther reveals four layers:the epidermis,endothecium,middle layer,and tapetum.The tapetum,being...Male gametes are produced in the anthers and are essential for fertilization and seed setting.A transverse section of the anther reveals four layers:the epidermis,endothecium,middle layer,and tapetum.The tapetum,being the innermost layer,plays a critical role in supplying nutrients,enzymes,and protection to microspores.Detailed microscopic and ultrastructural analyses have revealed highly active and well-organized structures within the tapetum,referred to as tapetal organelles.Molecular studies have highlighted the significance of tapetal cell death and the nurturing role of the tapetum for microspores.However,the mechanisms by which these processes are mediated by tapetal organelles at the cellular level remain elusive.The discovery of mutants defective in tapetal organelles has enabled further investigations into their structure,morphology,and function.This review discusses the molecular and functional roles of various tapetal organelles,such as plastids(amyloplasts and elaioplasts),mitochondria,tapetosomes,endoplasmic reticulum,and lipid bodies.We provide an overview of their roles,highlight key organelles in the tapetum,and address recent challenges and potential applications of genes regulating tapetal organelles in enhancing crop fertility.展开更多
The plastid genome(plastome)represents an indispensable molecular resource for studying plant phylogeny and evolution.Although plastome size is much smaller than that of nuclear genomes,accurately and efficientlyannot...The plastid genome(plastome)represents an indispensable molecular resource for studying plant phylogeny and evolution.Although plastome size is much smaller than that of nuclear genomes,accurately and efficientlyannotating and utilizing plastome sequences remain challenging.Therefore,a streamlined phylogenomic pipeline spanning plastome annotation,phylogenetic reconstruction and comparative genomics would greatly facilitate research utilizing this important organellar genome.Here,we develop PlastidHub,a novel web application employing innovative tools to analyze plastome sequences.In comparison with existing tools,key novel functionalities in PlastidHub include:(1)standardization of quadripartite structure;(2)improvement of annotation flexibility and consistency;(3)quantitative assessment of annotation completeness;(4)diverse extraction modes for canonical and specialized sequences;(5)intelligent screening of molecular markers for biodiversity studies;(6)genelevel visual comparison of structural variations and annotation completeness.PlastidHub features cloud-based web applications that do not require users to install,update,or maintain tools;detailed help documents including user guides,test examples,a static pop-up prompt box,and dynamic pop-up warning prompts when entering unreasonable parameter values;batch processing capabilities for all tools;intermediate results for secondary use;and easy-to-operate task flows between fileupload and download.A key feature of PlastidHub is its interrelated task-based user interface design.Give that PlastidHub is easy to use without specialized computational skills or resources,this new platform should be widely used among botanists and evolutionary biologists,improving and expediting research employing the plastome.PlastidHub is available at https://www.plastidhub.cn.展开更多
Carotenoids are indispensable to plants and critical in human diets. Plastids are the organelles for carotenoid biosynthesis and storage in plant cells. They exist in various types, which include proplastids, etioplas...Carotenoids are indispensable to plants and critical in human diets. Plastids are the organelles for carotenoid biosynthesis and storage in plant cells. They exist in various types, which include proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. These plastids have dramatic differences in their capacity to synthesize and sequester carotenoids. Clearly, plastids play a central role in governing carotenogenic activity, carotenoid stability, and pigment diversity. Understanding of carotenoid metabolism and accumulation in various plastids expands our view on the multifaceted regulation of carotenogenesis and facilitates our efforts toward developing nutrient-enriched food crops. In this review, we provide a comprehensive overview of the impact of various types of plastids on carotenoid biosynthesis and accumulation, and discuss recent advances in our understanding of the regulatory control of carotenogenesis and metabolic engineering of carotenoids in light of plastid types in plants.展开更多
Chloroplasts （plastids） possess a genome and their own machinery to express it. Translation in plastids occurs on bacterial-type 70S ribosomes utilizing a set of tRNAs that is entirely encoded in the plastid genome....Chloroplasts （plastids） possess a genome and their own machinery to express it. Translation in plastids occurs on bacterial-type 70S ribosomes utilizing a set of tRNAs that is entirely encoded in the plastid genome. In recent years, the components of the chloroplast translational apparatus have been intensely studied by proteomic approaches and by reverse genetics in the model systems tobacco （plastid-encoded components） and Arabidopsis （nucleus-encoded components）. This work has provided important new insights into the structure, function, and biogenesis of chloroplast ribosomes, and also has shed fresh light on the molecular mechanisms of the translation process in plastids. In addition, mutants affected in plastid translation have yielded strong genetic evidence for chloroplast genes and gene products influencing plant develop- ment at various levels, presumably via retrograde signaling pathway（s）. In this review, we describe recent progress with the functional analysis of components of the chloroplast translational machinery and discuss the currently available evidence that supports a significant impact of plastid translational activity on plant anatomy and morphology.展开更多
RNA interference(RNAi)has emerged as a powerful technology for pest management.Previously,we have shown that plastid-mediated RNAi(PM-RNAi)can be utilized to control the Colorado potato beetle,an insect pest in the Ch...RNA interference(RNAi)has emerged as a powerful technology for pest management.Previously,we have shown that plastid-mediated RNAi(PM-RNAi)can be utilized to control the Colorado potato beetle,an insect pest in the Chrysomelidae family;however,whether this technology is suitable for controlling pests in the Coccinellidae remained unknown.The coccinellid 28-spotted potato ladybird(Henosepilachna vigintioctopunctata;HV)is a serious pest of solanaceous crops.In this study,we identified three efficient target genes(β-Actin,SRP54,and SNAP)for RNAi using in vitro double-stranded RNAs(dsRNAs)fed to HV,and found that dsRNAs targetingβ-Actin messenger RNA(dsACT)induced more potent RNAi than those targeting the other two genes.We next generated transplastomic and nuclear transgenic potato(Solanum tuberosum)plants expressing HV dsACT.Long dsACT stably accumulated to up to 0.7%of the total cellular RNA in the transplastomic plants,at least three orders of magnitude higher than in the nuclear transgenic plants.Notably,the transplastomic plants also exhibited a significantly stronger resistance to HV,killing all larvae within 6 d.Our data demonstrate the potential of PM-RNAi as an efficient pest control measure for HV,extending the application range of this technology to Coccinellidae pests.展开更多
As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division...As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.展开更多
The inheritance of plastid DNA in Pharbitis was studied by the method of restriction fragment length polymorphisms (RFLP).Experimental results showed that plastid DNA from Pharbitis was paternally inherited in recipro...The inheritance of plastid DNA in Pharbitis was studied by the method of restriction fragment length polymorphisms (RFLP).Experimental results showed that plastid DNA from Pharbitis was paternally inherited in reciprocal crosses,P. nil ×P. limbata and P. limbata×P. nil hybrids.But,in the cross of P. limbata×P. nil,the possibility of biparental inheritance of plastid DNA could not be roled out in our preliminary experiment.Thus Pharbitis became the third genus among angiosperms characterized with male plastid transmission.The mechanisms of paternal plastids DNA inheritance in Pharbitis is unclear.The authors proposed that dilution,exclusion and/or degeneration of maternal plastid,including their DNA,after fertilization should be considered.展开更多
The inheritance of chloroplast DNA (cpDNA) in sweet potato (Ipomoea batatas Lain.) was analyzed using DNA restriction fingerprinting. The cpDNA fingerprints of hybrids from reciprocal crosses between Xushu18 and AB78-...The inheritance of chloroplast DNA (cpDNA) in sweet potato (Ipomoea batatas Lain.) was analyzed using DNA restriction fingerprinting. The cpDNA fingerprints of hybrids from reciprocal crosses between Xushu18 and AB78-1 were found to be identical to those of their female parents, which reveals that cpDNA of sweet potato is maternally inherited in this intervarietal crossing. This maternal cpDNA transmission pattern does not accord with the putative one based on former cytological studies. The plastid inheritance in Convolvulaceae has been briefly reviewed in this study, and the utility of DNA restriction fingerprinting analysis in the study of plastid inheritance is also discussed.展开更多
Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the fil...Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the filamentous bacteria indicated that the NtFtsZs could recognize the potential division sites in E. coli and be polymerized with heterogeneous FtsZ from bacteria. The overexpression of NtFtsZs ∶ gfp inhibited the division of host strain cells and resulted in the long filamentous bacterial morphology. These results suggested that eukaryotic ftsZs have similar function to their prokaryotic homologs. Meanwhile, the different deletions of motifs of NtFtsZs are also employed to investigate the functions of these proteins in E. coli . The results showed that the C_terminal domains of NtFtsZs were related to the correct localization of NtFtsZs in E. coli and the N_terminal domains of NtFtsZs were responsible for the polymerization of homogeneous and heterogeneous FtsZ proteins. The significance of these results in understanding the functions of NtFtsZs in plastid division were discussed.展开更多
文摘Starch degradation in cells is closely associated with cereal seed germination, photosynthesis in leaves, carbohydrate storage in tuber and tuberous roots, and fleshy fruit development. Based on previously reported in vitro assays, β amylase is considered as one of the key enzymes catalyzing starch breakdown, but up to date its role in starch breakdown in living cells remains unclear because the enzyme was shown often extrachloroplastic in living cells. Recently we have shown for the first time that β_amylase is predominantly immuno_localized to plastids in living cells of developing apple fruit. But it remains to know whether this model of β_amylase compartmentation is more widespread in plant living cells. The present experiment, conducted in tuberous root of sweet potato ( Ipomea batatas Lam. cv. Xushu 18) and via immunogold electron_microscopy technique, showed that β amylase visualized by gold particles was predominantly localized in plastids especially at periphery of starch granules, but the gold particles were scarcely found in other subcellular compartments, indicating that the enzyme is subcellularly compartmented in the same zone as its starch substrates. The density of gold particles (β amylase) in plastids was increasing during growing season, but the predominantly plastid_distributed pattern of β amylase in cells was shown unchanged throughout the tuberous root development. These data prove that the enzyme is compartmented in its functional sites, and so provide evidence to support the possible widespread biological function of the enzyme in catalyzing starch breakdown in plant living cells or at least in living cells of plant storage organs.
基金Supported by a grant from the Hong Kong Research Grant Council, No. 7342/03M to YX Zhou and E Lam
文摘AIM： To cost-effectively express the 23-ku pE2, the most promising subunit vaccine encoded by the E2 fragment comprising of the 3＇-portion of hepatitis E virus （HEV） open reading frame 2 （ORF2） in plastids of tobacco （Nicotiana tabacum cv. SR1）, to investigate the transgene expression and pE2 accumulation in plastids, and to evaluate the antigenic effect of the plastid-derived pE2 in mice. METHODS： Plastid-targeting vector pRB94-E2 containing the E2 fragment driven by rice psbA promoter was constructed. Upon delivery into tobacco plastids, this construct could initiate homologous recombination in psaB-trnfM and trnG-psbC fragments in plastid genome, and result in transgene inserted between the two fragments. The pRB94-E2 was delivered with a biolistic particle bombardment method, and the plastid-transformed plants were obtained following the regeneration of the bombarded leaf tissues on a spectinomycin-supplemented medium. Transplastomic status of the regenerated plants was confirmed by PCR and Southern blot analysis, transgene expression was investigated by Northern blot analysis, and accumulation of pE2 was measured by ELISA. Furthermore, protein extracts were used to immunize mice, and the presence of the pE2-reactive antibodies in serum samples of the immunized mice was studied by ELISA. RESULTS： Transplastomic lines confirmed by PCR and Southern blot analysis could actively transcribe the E2 mRNA. The pE2 polypeptide was accumulated to a level as high as 13.27 μg/g fresh leaves. The pE2 could stimulate the immunized mice to generate pE2-specific antibodies. CONCLUSION： HEV-E2 fragment can be inserted into the plastid genome and the recombinant pE2 antigen derived is antigenic in mice. Hence, plastids may be a novel source for cost-effective production of HEV vaccines.
基金supported by the National Natural Science Foundation of China(32150710517)the Huazhong Agricultural University Scientific&Technological SelfInnovation Foundation(2016RC009)the National Key Research and Development Program of China,Ministry of Science and Education(2018YFD1000800).
文摘Mechanisms that allocate cellular space to organelles are of fundamental importance to biology but remain poorly understood.A detailed understanding of mechanisms that allocate cellular space to plastids,such as chloroplasts,will lead to high-yielding crops with enhanced nutritional value.The HIGH PIGMENT(HP)genes in tomato contribute to regulated proteolysis and abscisic acid metabolism.The HP1 gene was the first gene reported to influence the amount of cellular space occupied by chloroplasts and chromoplasts almost 20 years ago.Recently,our knowledge of mechanisms that allocate cellular space to plastids was enhanced by new information on the influence of cell type on the amount of cellular space occupied by plastids and the identification of new genes that help to allocate cellular space to plastids.These genes encode proteins with unknown and diverse biochemical functions.Several transcription factors were recently reported to regulate the numbers and sizes of chloroplasts in fleshy fruit.If these transcription factors do not induce compensating effects on cell size,they should affect the amount of cellular space occupied by plastids.Although we can now propose more detailed models for the network that allocates cellular space to plastids,many gaps remain in our knowledge of this network and the genes targeted by this network.Nonetheless,these recent breakthroughs provide optimism for future progress in this field.
基金supported by the Zhejiang Provincial Natural Science Foundation of China(Grant Nos.LQ23C150004 and LR23C150001)National Natural Science Foundation of China(NSFC+1 种基金Grant No.32102318)NSFC Excellent Young Scientists Fund,and the Key Project for New Agricultural Cultivar Breeding in Zhejiang Province,China(Grant No.2021C02066-1).
文摘Chlorophyll degradation and carotenoid accumulation are essential processes of fruit maturation in many horticultural plants,and play a crucial role in fruit color and quality.The pathways of chlorophyll and carotenoid biosynthesis and degradation are well understood,and key regulatory genes controlling these pathways have been identified in citrus.This article reviewed the recent research on chlorophyll and carotenoid metabolism in citrus fruits,encompassing the metabolic pathways,transcriptional regulation,influencing factors,and the interplay between chlorophyll and carotenoid metabolism,aiming to provide insights into the molecular regulatory mechanisms governing the coloration of citrus fruits.
基金supported by the National Key Research and Development Program of China(2022YFD1200704-3)Crop Varietal Improvement and Insect Pests Control by Nuclear Radiation,the Sichuan Province Science and Technology Program(2022NSFSC0018,2021YFYZ0011,2020YJ0249,MZGC20230108)the Biological Breeding Program of State Key of Sichuan Agricultural University(SKL-ZY202234).
文摘Carotenoids are the largest group of natural pigments responsible for the yellow,orange,and red colors in plant kernels,fruits,and leaves(Gupta and Hirschberg,2021).In plants,carotenoids are involved in manybiological processes,such as acting as accessory light-harvesting pigments in photosynthesis,participating in photoprotection,and serving as precursors for the hormones abscisic acid(ABA)and strigolactones(Ruiz-Sola and Rodriguez-Concepcion,2012).
基金supported by the National Natural Science Foundation of China(Grant Nos.32272191 and 32350410428).
文摘Male gametes are produced in the anthers and are essential for fertilization and seed setting.A transverse section of the anther reveals four layers:the epidermis,endothecium,middle layer,and tapetum.The tapetum,being the innermost layer,plays a critical role in supplying nutrients,enzymes,and protection to microspores.Detailed microscopic and ultrastructural analyses have revealed highly active and well-organized structures within the tapetum,referred to as tapetal organelles.Molecular studies have highlighted the significance of tapetal cell death and the nurturing role of the tapetum for microspores.However,the mechanisms by which these processes are mediated by tapetal organelles at the cellular level remain elusive.The discovery of mutants defective in tapetal organelles has enabled further investigations into their structure,morphology,and function.This review discusses the molecular and functional roles of various tapetal organelles,such as plastids(amyloplasts and elaioplasts),mitochondria,tapetosomes,endoplasmic reticulum,and lipid bodies.We provide an overview of their roles,highlight key organelles in the tapetum,and address recent challenges and potential applications of genes regulating tapetal organelles in enhancing crop fertility.
基金the Natural Science Foundation of Shandong Province(ZR2020QC022)the Science and Technology Basic Resources Investigation Program of China(No.2019FY100900)+2 种基金the Major Program for Basic Research Project of Yunnan Province(202401BC070001)Yunnan Revitalization Talent Support Program:Yunling Scholar Project to Tingshuang Yithe open research project of“Cross Cooperative Team”of the Germplasm Bank of Wild Species,Kunming Institute of Botany,Chinese Academy of Sciences.
文摘The plastid genome(plastome)represents an indispensable molecular resource for studying plant phylogeny and evolution.Although plastome size is much smaller than that of nuclear genomes,accurately and efficientlyannotating and utilizing plastome sequences remain challenging.Therefore,a streamlined phylogenomic pipeline spanning plastome annotation,phylogenetic reconstruction and comparative genomics would greatly facilitate research utilizing this important organellar genome.Here,we develop PlastidHub,a novel web application employing innovative tools to analyze plastome sequences.In comparison with existing tools,key novel functionalities in PlastidHub include:(1)standardization of quadripartite structure;(2)improvement of annotation flexibility and consistency;(3)quantitative assessment of annotation completeness;(4)diverse extraction modes for canonical and specialized sequences;(5)intelligent screening of molecular markers for biodiversity studies;(6)genelevel visual comparison of structural variations and annotation completeness.PlastidHub features cloud-based web applications that do not require users to install,update,or maintain tools;detailed help documents including user guides,test examples,a static pop-up prompt box,and dynamic pop-up warning prompts when entering unreasonable parameter values;batch processing capabilities for all tools;intermediate results for secondary use;and easy-to-operate task flows between fileupload and download.A key feature of PlastidHub is its interrelated task-based user interface design.Give that PlastidHub is easy to use without specialized computational skills or resources,this new platform should be widely used among botanists and evolutionary biologists,improving and expediting research employing the plastome.PlastidHub is available at https://www.plastidhub.cn.
文摘Carotenoids are indispensable to plants and critical in human diets. Plastids are the organelles for carotenoid biosynthesis and storage in plant cells. They exist in various types, which include proplastids, etioplasts, chloroplasts, amyloplasts, and chromoplasts. These plastids have dramatic differences in their capacity to synthesize and sequester carotenoids. Clearly, plastids play a central role in governing carotenogenic activity, carotenoid stability, and pigment diversity. Understanding of carotenoid metabolism and accumulation in various plastids expands our view on the multifaceted regulation of carotenogenesis and facilitates our efforts toward developing nutrient-enriched food crops. In this review, we provide a comprehensive overview of the impact of various types of plastids on carotenoid biosynthesis and accumulation, and discuss recent advances in our understanding of the regulatory control of carotenogenesis and metabolic engineering of carotenoids in light of plastid types in plants.
文摘Chloroplasts （plastids） possess a genome and their own machinery to express it. Translation in plastids occurs on bacterial-type 70S ribosomes utilizing a set of tRNAs that is entirely encoded in the plastid genome. In recent years, the components of the chloroplast translational apparatus have been intensely studied by proteomic approaches and by reverse genetics in the model systems tobacco （plastid-encoded components） and Arabidopsis （nucleus-encoded components）. This work has provided important new insights into the structure, function, and biogenesis of chloroplast ribosomes, and also has shed fresh light on the molecular mechanisms of the translation process in plastids. In addition, mutants affected in plastid translation have yielded strong genetic evidence for chloroplast genes and gene products influencing plant develop- ment at various levels, presumably via retrograde signaling pathway（s）. In this review, we describe recent progress with the functional analysis of components of the chloroplast translational machinery and discuss the currently available evidence that supports a significant impact of plastid translational activity on plant anatomy and morphology.
基金supported by grants from the Natural Science Foundation of Hubei Province(2020CFA012)the National Natural Science Foundation of China(32271912)to J.Z。
文摘RNA interference(RNAi)has emerged as a powerful technology for pest management.Previously,we have shown that plastid-mediated RNAi(PM-RNAi)can be utilized to control the Colorado potato beetle,an insect pest in the Chrysomelidae family;however,whether this technology is suitable for controlling pests in the Coccinellidae remained unknown.The coccinellid 28-spotted potato ladybird(Henosepilachna vigintioctopunctata;HV)is a serious pest of solanaceous crops.In this study,we identified three efficient target genes(β-Actin,SRP54,and SNAP)for RNAi using in vitro double-stranded RNAs(dsRNAs)fed to HV,and found that dsRNAs targetingβ-Actin messenger RNA(dsACT)induced more potent RNAi than those targeting the other two genes.We next generated transplastomic and nuclear transgenic potato(Solanum tuberosum)plants expressing HV dsACT.Long dsACT stably accumulated to up to 0.7%of the total cellular RNA in the transplastomic plants,at least three orders of magnitude higher than in the nuclear transgenic plants.Notably,the transplastomic plants also exhibited a significantly stronger resistance to HV,killing all larvae within 6 d.Our data demonstrate the potential of PM-RNAi as an efficient pest control measure for HV,extending the application range of this technology to Coccinellidae pests.
文摘As an important group of plant cellular organelles, the molecular mechanism of plastid division is poorly understood. Recent studies have revealed that the homologs of ftsZ gene, an essential prokaryotic cell division gene, are involved in plastid division process of plant cells. Antisense and sense expression constructions were employed to investigate the functions of the two ftsZ genes, NtFtsZ1 and NtFtsZ2, in transgenic Nicotiana tabacum L. plants. Although antisense expression of,NtFtsZs reduced the native protein level obviously, the size and number of chloroplasts in transgenic tobacco plants had no effect. In contrast, overexpression of NtFtsZs in transgenic plants strikingly changed the number and morphology of chloroplasts. Even only 1 - 2 huge chloroplasts could be seen in the mesophyll cells of some overexpression transgenic plants. Analyses of chloroplast ultrastructures and chlorophyll content of different transgenic plants suggested that NtFtsZs gene have no direct influence on the normal development and function of chloroplasts. ne changes in chloroplast morphology must be a compensation for the change in chloroplast number. The different phenotypes of chloroplasts in antisense and sense transgenic plants implied that different members from the same ftsZ gene family may have similar function in controlling plastid division. Meanwhile, the changes of chloroplast morphology in sense transgenic plants represented the possible plastoskeleton function of ftsZ in higher plant.
文摘The inheritance of plastid DNA in Pharbitis was studied by the method of restriction fragment length polymorphisms (RFLP).Experimental results showed that plastid DNA from Pharbitis was paternally inherited in reciprocal crosses,P. nil ×P. limbata and P. limbata×P. nil hybrids.But,in the cross of P. limbata×P. nil,the possibility of biparental inheritance of plastid DNA could not be roled out in our preliminary experiment.Thus Pharbitis became the third genus among angiosperms characterized with male plastid transmission.The mechanisms of paternal plastids DNA inheritance in Pharbitis is unclear.The authors proposed that dilution,exclusion and/or degeneration of maternal plastid,including their DNA,after fertilization should be considered.
文摘The inheritance of chloroplast DNA (cpDNA) in sweet potato (Ipomoea batatas Lain.) was analyzed using DNA restriction fingerprinting. The cpDNA fingerprints of hybrids from reciprocal crosses between Xushu18 and AB78-1 were found to be identical to those of their female parents, which reveals that cpDNA of sweet potato is maternally inherited in this intervarietal crossing. This maternal cpDNA transmission pattern does not accord with the putative one based on former cytological studies. The plastid inheritance in Convolvulaceae has been briefly reviewed in this study, and the utility of DNA restriction fingerprinting analysis in the study of plastid inheritance is also discussed.
文摘Two plastid division genes, NtFtsZ1 and NtFtsZ2 isolated from Nicotiana tabacum L. were fused with gfp and expressed in Escherichia coli . The regular localizations of full length NtFtsZs∶GFP along the filamentous bacteria indicated that the NtFtsZs could recognize the potential division sites in E. coli and be polymerized with heterogeneous FtsZ from bacteria. The overexpression of NtFtsZs ∶ gfp inhibited the division of host strain cells and resulted in the long filamentous bacterial morphology. These results suggested that eukaryotic ftsZs have similar function to their prokaryotic homologs. Meanwhile, the different deletions of motifs of NtFtsZs are also employed to investigate the functions of these proteins in E. coli . The results showed that the C_terminal domains of NtFtsZs were related to the correct localization of NtFtsZs in E. coli and the N_terminal domains of NtFtsZs were responsible for the polymerization of homogeneous and heterogeneous FtsZ proteins. The significance of these results in understanding the functions of NtFtsZs in plastid division were discussed.
