Ultracytochemical localization of ATPase during development of rice endosperm was performed using a lead phosphate precipitation technique. The results indicated that, at the coenocyte and cellularization stages, acti...Ultracytochemical localization of ATPase during development of rice endosperm was performed using a lead phosphate precipitation technique. The results indicated that, at the coenocyte and cellularization stages, active ATPase was mainly distributed in an embryo sac wall, nucleus, and plasma membrane. At the early stage of development and differentiation, active ATPase was observed in the plasma membrane. At the grain filling stage, ATPase was highly active in the plasma membrane, intercellular space, and plasmodesmata in aleurone, moderately active on the plasma membrane in subaleurone. In starchy endosperm, ATPase was localized in the plasma membrane and degenerated nucleus. ATPase activity also appeared around vacuole and protein body in endosperm cell. The relationships between the ultracytochemical localization of ATPase and its function during the development of rice endosperm were discussed. Overall, ATPase was involved in the process of nutrition absorption and protein synthesis.展开更多
Most of the reported P-type pentatricopeptide repeat(PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and ...Most of the reported P-type pentatricopeptide repeat(PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and their underlying mechanism remains largely unknown. Here, we report a rice floury endosperm22(flo22) mutant with delayed amyloplast development in endosperm cells. Map-based cloning and complementation tests demonstrated that FLO22 encodes a mitochondrion-localized P-type PPR protein.Mutation of FLO22 resulting in defective transsplicing of mitochondrial nad1 intron 1 and perhaps causing instability of mature transcripts affected assembly and activity of complex Ⅰ, and mitochondrial morphology and function. RNA-seq analysis showed that expression levels of many genes involved in starch and sucrose metabolism were significantly down-regulated in the flo22mutant compared with the wild type, whereas genes related to oxidative phosphorylation and the tricarboxylic acid cycle were significantly upregulated. In addition to involvement in splicing as a P-type PPR protein, we found that FLO22 interacted with DYW3, a DYW-type PPR protein, and they may function synergistically in mitochondrial RNA editing. The present work indicated that FLO22 plays an important role in endosperm development and plant growth by participating in nad1 maturation and multi-site editing of mitochondrial messager RNA.展开更多
Pentatricopeptide repeat(PPR) proteins, composing one of the largest protein families in plants,are involved in RNA binding and regulation of organelle RNA metabolism at the posttranscriptional level. Although several...Pentatricopeptide repeat(PPR) proteins, composing one of the largest protein families in plants,are involved in RNA binding and regulation of organelle RNA metabolism at the posttranscriptional level. Although several PPR proteins have been implicated in endosperm development in rice(Oryza sativa), the molecular functions of many PPRs remain obscure. Here, we identified a rice endosperm mutant named floury endosperm 18(flo18) with pleiotropic defects in both reproductive and vegetative development.Map-based cloning and complementation tests showed that FLO18 encodes a mitochondriontargeted P-type PPR protein with 15 PPR motifs.Mitochondrial function was disrupted in the flo18 mutant, as evidenced by decreased assembly of Complex I in the mitochondrial electron transport chain and altered mitochondrial morphology. Loss of FLO18 function resulted in defective 5′-end processing of mitochondrial nad5 transcripts encoding subunit 5 of nicotinamide adenine dinucleotide hydrogenase. These results suggested that FLO18 is involved in 5′-end processing of nad5 messenger RNA and plays an important role in mitochondrial function and endosperm development.展开更多
Traditional upland rice generally exhibits insufficient grains resulting from abnormal endosperm development compared to paddy rice. However, the underlying molecular mechanism of this trait is poorly understood. Here...Traditional upland rice generally exhibits insufficient grains resulting from abnormal endosperm development compared to paddy rice. However, the underlying molecular mechanism of this trait is poorly understood. Here,we cloned the uridine 5’-diphospho(UDP)-glucosyltransferase gene EDR1(Endosperm Development in Rice) responsible for differential endosperm development between upland rice and paddy rice by performing quantitative trait loci analysis and map-based cloning. EDR1 was highly expressed in developing seeds duringgrain filling. Natural variations in EDR1 significantly reduced the UDP-glucosyltransferase activity of EDR1 YZNcompared to EDR1 YD1,resulting in abnormal endosperm development in the near-isogenic line, accompanied by insufficient grains and changes in grain quality.By analyzing the distribution of the two alleles EDR1 YD1 and EDR1 YZNamong diverse paddy rice and upland rice varieties, we discovered that EDR1 was conserved in upland rice, but segregated in paddy rice. Further analyses of grain chalkiness in the alleles of EDR1 YD1 and EDR1 YZNvarieties indicated that rice varieties harboring EDR1 YZNand EDR1 YD1 preferentially showed high chalkiness, and low chalkiness,respectively. Taken together, these results suggest that the UDP-glucosyltransferase gene EDR1 is an important determinant controlling differential endosperm development between upland rice and paddy rice.展开更多
Recent breakthroughs in transcriptome analysis and gene characterization have provided valuable resources and information about the maize endosperm developmental program.The high temporal-resolution transcriptome anal...Recent breakthroughs in transcriptome analysis and gene characterization have provided valuable resources and information about the maize endosperm developmental program.The high temporal-resolution transcriptome analysis has yielded unprecedented access to information about the genetic control of seed development.Detailed spatial transcriptome analysis using laser-capture microdissection has revealed the expression patterns of specific populations of genes in the four major endosperm compartments:the basal endosperm transfer layer(BETL),aleurone layer(AL),starchy endosperm(SE),and embryo-surrounding region(ESR).Although the overall picture of the transcriptional regulatory network of endosperm development remains fragmentary,there have been some exciting advances,such as the identification of OPAQUE11(O11)as a central hub of the maize endosperm regulatory network connecting endosperm development,nutrient metabolism,and stress responses,and the discovery that the endosperm adjacent to scutellum(EAS)serves as a dynamic interface for endosperm-embryo crosstalk.In addition,several genes that function in BETL development,AL differentiation,and the endosperm cell cycle have been identified,such as ZmSWEET4c,Thk1,and Dek15,respectively.Here,we focus on current advances in understanding the molecular factors involved in BETL,AL,SE,ESR,and EAS development,including the specific transcriptional regulatory networks that function in each compartment during endosperm development.展开更多
Starch is a vital energy source for living organisms and is a key raw material and additive in the food and non-food industries.Starch has received continuous attention in multiple research fields.The endosperm of cer...Starch is a vital energy source for living organisms and is a key raw material and additive in the food and non-food industries.Starch has received continuous attention in multiple research fields.The endosperm of cereals(e.g.,rice,corn,wheat,and barley)is the most important site for the synthesis of storage starch.Around 2010,several excellent reviews summarized key progress in various fields of starch research,serving as important references for subsequent research.In the past 10 years,many achievements have been made in the study of starch synthesis and regulation in cereals.The present review provides an update on research progress in starch synthesis of cereal endosperms over the past decade,focusing on new enzymes and non-enzymatic proteins involved in starch synthesis,regulatory networks of starch synthesis,and the use of elite alleles of starch synthesis-related genes in cereal breeding programs.We also provide perspectives on future research directions that will further our understanding of cereal starch biosynthesis and regulation to support the rational design of ideal quality grain.展开更多
In plants, RNA editing is a post-transcriptional process that changes specific cytidine to uridine in both mitochondria and plastids. Most pentatricopeptide repeat(PPR) proteins are involved in organelle RNA editing...In plants, RNA editing is a post-transcriptional process that changes specific cytidine to uridine in both mitochondria and plastids. Most pentatricopeptide repeat(PPR) proteins are involved in organelle RNA editing by recognizing specific RNA sequences. We here report the functional characterization of a PPR protein from the DYW subclass, Baili Xi(BLX), which contains five PPR motifs and a DYW domain. BLX is essential for early seed development, as plants lacking the BLX gene was embryo lethal and the endosperm failed to initiate cellularization. BLX was highly expressed in the embryo and endosperm, and the BLX protein was specifically localized in mitochondria, which is essential for BLX function. We found that BLX was required for the efficient editing of 36 editing sites in mitochondria. Moreover, BLX was involved in the splicing regulation of the fourth intron of nad1 and the first intron of nad2. The loss of BLX function impaired the mitochondrial function and increased the reactive oxygen species(ROS) level. Genetic complementation with truncated variants of BLX revealed that, in addition to the DYW domain, only the fifth PPR motif was essential for BLX function. The upstream sequences of the BLX-targeted editing sites are not conserved, suggesting that BLX serves as a novel and major mitochondrial editing factor(MEF) via a new non-RNA-interacting manner. This finding provides new insights into how a DYW-type PPR protein with fewer PPR motifs regulates RNA editing in plants.展开更多
基金supported by the National Natural Science Foundation of China(30070363) the Research Foundation for Doctorate in Universities of China(2000050401).
文摘Ultracytochemical localization of ATPase during development of rice endosperm was performed using a lead phosphate precipitation technique. The results indicated that, at the coenocyte and cellularization stages, active ATPase was mainly distributed in an embryo sac wall, nucleus, and plasma membrane. At the early stage of development and differentiation, active ATPase was observed in the plasma membrane. At the grain filling stage, ATPase was highly active in the plasma membrane, intercellular space, and plasmodesmata in aleurone, moderately active on the plasma membrane in subaleurone. In starchy endosperm, ATPase was localized in the plasma membrane and degenerated nucleus. ATPase activity also appeared around vacuole and protein body in endosperm cell. The relationships between the ultracytochemical localization of ATPase and its function during the development of rice endosperm were discussed. Overall, ATPase was involved in the process of nutrition absorption and protein synthesis.
基金supported by grants from the National Key R&D Program of China (2021YFF1000200)National Natural Science Foundation of China (31901513)+6 种基金the “JBGS” Project of Seed Industry Revitalization in Jiangsu Province (JBGS [2021]008)Jiangsu Province Agriculture Independent Innovation Fund Project (CX(19)1002)the Fundamental Research Funds for the Central Universities (KJQN202005)the China Postdoctoral Science Foundation (2019M661864)also supported by the Key Laboratory of Biology, Genetics, and Breeding of Japonica Rice in Mid-lower Yangtze River, Ministry of Agriculture, Chinathe Jiangsu Collaborative Innovation Center for Modern Crop ProductionNational Observation and Research Station of Rice Germplasm Resources, Nanjing, Jiangsu。
文摘Most of the reported P-type pentatricopeptide repeat(PPR) proteins play roles in organelle RNA stabilization and splicing. However, P-type PPRs involved in both RNA splicing and editing have rarely been reported, and their underlying mechanism remains largely unknown. Here, we report a rice floury endosperm22(flo22) mutant with delayed amyloplast development in endosperm cells. Map-based cloning and complementation tests demonstrated that FLO22 encodes a mitochondrion-localized P-type PPR protein.Mutation of FLO22 resulting in defective transsplicing of mitochondrial nad1 intron 1 and perhaps causing instability of mature transcripts affected assembly and activity of complex Ⅰ, and mitochondrial morphology and function. RNA-seq analysis showed that expression levels of many genes involved in starch and sucrose metabolism were significantly down-regulated in the flo22mutant compared with the wild type, whereas genes related to oxidative phosphorylation and the tricarboxylic acid cycle were significantly upregulated. In addition to involvement in splicing as a P-type PPR protein, we found that FLO22 interacted with DYW3, a DYW-type PPR protein, and they may function synergistically in mitochondrial RNA editing. The present work indicated that FLO22 plays an important role in endosperm development and plant growth by participating in nad1 maturation and multi-site editing of mitochondrial messager RNA.
基金This research was supported by grants from the National Transgenic Science and Technology Program(2019ZX08010-003)the Agricultural Science and Technology Innovation Program of CAAS(CAAS-ZDXT2018001)+1 种基金the Fundamental Research Funds for the Central Universities(KYTZ201601)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18_0657)。
文摘Pentatricopeptide repeat(PPR) proteins, composing one of the largest protein families in plants,are involved in RNA binding and regulation of organelle RNA metabolism at the posttranscriptional level. Although several PPR proteins have been implicated in endosperm development in rice(Oryza sativa), the molecular functions of many PPRs remain obscure. Here, we identified a rice endosperm mutant named floury endosperm 18(flo18) with pleiotropic defects in both reproductive and vegetative development.Map-based cloning and complementation tests showed that FLO18 encodes a mitochondriontargeted P-type PPR protein with 15 PPR motifs.Mitochondrial function was disrupted in the flo18 mutant, as evidenced by decreased assembly of Complex I in the mitochondrial electron transport chain and altered mitochondrial morphology. Loss of FLO18 function resulted in defective 5′-end processing of mitochondrial nad5 transcripts encoding subunit 5 of nicotinamide adenine dinucleotide hydrogenase. These results suggested that FLO18 is involved in 5′-end processing of nad5 messenger RNA and plays an important role in mitochondrial function and endosperm development.
基金supported by the National Natural Science Foundation of China(Grant Nos.U1702231,31360330,31902110)The Science and Technology Projects of Yunnan Province,China(Grant No.202003AD150007)+1 种基金Strategic Leading Science and Technology Program of Chinese Academy of Sciences(Grant Nos.XDA24030301 and XDA24040308)Natural Science Foundation of Yunnan,China(Grant No.2018FA 023)。
文摘Traditional upland rice generally exhibits insufficient grains resulting from abnormal endosperm development compared to paddy rice. However, the underlying molecular mechanism of this trait is poorly understood. Here,we cloned the uridine 5’-diphospho(UDP)-glucosyltransferase gene EDR1(Endosperm Development in Rice) responsible for differential endosperm development between upland rice and paddy rice by performing quantitative trait loci analysis and map-based cloning. EDR1 was highly expressed in developing seeds duringgrain filling. Natural variations in EDR1 significantly reduced the UDP-glucosyltransferase activity of EDR1 YZNcompared to EDR1 YD1,resulting in abnormal endosperm development in the near-isogenic line, accompanied by insufficient grains and changes in grain quality.By analyzing the distribution of the two alleles EDR1 YD1 and EDR1 YZNamong diverse paddy rice and upland rice varieties, we discovered that EDR1 was conserved in upland rice, but segregated in paddy rice. Further analyses of grain chalkiness in the alleles of EDR1 YD1 and EDR1 YZNvarieties indicated that rice varieties harboring EDR1 YZNand EDR1 YD1 preferentially showed high chalkiness, and low chalkiness,respectively. Taken together, these results suggest that the UDP-glucosyltransferase gene EDR1 is an important determinant controlling differential endosperm development between upland rice and paddy rice.
基金supported by the National Natural Science Foundation of China(grants 91935305 and 31730065 to R.S.).
文摘Recent breakthroughs in transcriptome analysis and gene characterization have provided valuable resources and information about the maize endosperm developmental program.The high temporal-resolution transcriptome analysis has yielded unprecedented access to information about the genetic control of seed development.Detailed spatial transcriptome analysis using laser-capture microdissection has revealed the expression patterns of specific populations of genes in the four major endosperm compartments:the basal endosperm transfer layer(BETL),aleurone layer(AL),starchy endosperm(SE),and embryo-surrounding region(ESR).Although the overall picture of the transcriptional regulatory network of endosperm development remains fragmentary,there have been some exciting advances,such as the identification of OPAQUE11(O11)as a central hub of the maize endosperm regulatory network connecting endosperm development,nutrient metabolism,and stress responses,and the discovery that the endosperm adjacent to scutellum(EAS)serves as a dynamic interface for endosperm-embryo crosstalk.In addition,several genes that function in BETL development,AL differentiation,and the endosperm cell cycle have been identified,such as ZmSWEET4c,Thk1,and Dek15,respectively.Here,we focus on current advances in understanding the molecular factors involved in BETL,AL,SE,ESR,and EAS development,including the specific transcriptional regulatory networks that function in each compartment during endosperm development.
基金supported by grants from the National Natural Science Foundation of China(grant numbers 31825019,32072032,and 31901517)the PAPD Programs from Jiangsu Province Government.
文摘Starch is a vital energy source for living organisms and is a key raw material and additive in the food and non-food industries.Starch has received continuous attention in multiple research fields.The endosperm of cereals(e.g.,rice,corn,wheat,and barley)is the most important site for the synthesis of storage starch.Around 2010,several excellent reviews summarized key progress in various fields of starch research,serving as important references for subsequent research.In the past 10 years,many achievements have been made in the study of starch synthesis and regulation in cereals.The present review provides an update on research progress in starch synthesis of cereal endosperms over the past decade,focusing on new enzymes and non-enzymatic proteins involved in starch synthesis,regulatory networks of starch synthesis,and the use of elite alleles of starch synthesis-related genes in cereal breeding programs.We also provide perspectives on future research directions that will further our understanding of cereal starch biosynthesis and regulation to support the rational design of ideal quality grain.
基金supported by the National Natural Science Foundation of China(Nos.31620103903 and 31621001)partially by the 111 projectsupported by the Peking-Tsinghua Joint Center for Life Sciences
文摘In plants, RNA editing is a post-transcriptional process that changes specific cytidine to uridine in both mitochondria and plastids. Most pentatricopeptide repeat(PPR) proteins are involved in organelle RNA editing by recognizing specific RNA sequences. We here report the functional characterization of a PPR protein from the DYW subclass, Baili Xi(BLX), which contains five PPR motifs and a DYW domain. BLX is essential for early seed development, as plants lacking the BLX gene was embryo lethal and the endosperm failed to initiate cellularization. BLX was highly expressed in the embryo and endosperm, and the BLX protein was specifically localized in mitochondria, which is essential for BLX function. We found that BLX was required for the efficient editing of 36 editing sites in mitochondria. Moreover, BLX was involved in the splicing regulation of the fourth intron of nad1 and the first intron of nad2. The loss of BLX function impaired the mitochondrial function and increased the reactive oxygen species(ROS) level. Genetic complementation with truncated variants of BLX revealed that, in addition to the DYW domain, only the fifth PPR motif was essential for BLX function. The upstream sequences of the BLX-targeted editing sites are not conserved, suggesting that BLX serves as a novel and major mitochondrial editing factor(MEF) via a new non-RNA-interacting manner. This finding provides new insights into how a DYW-type PPR protein with fewer PPR motifs regulates RNA editing in plants.