In cereal crops,the endosperm synthesizes large quantities of proteins,including storage proteins and functional factors essential for the accumulation of storage reserves.The unfolded protein response(UPR)monitors th...In cereal crops,the endosperm synthesizes large quantities of proteins,including storage proteins and functional factors essential for the accumulation of storage reserves.The unfolded protein response(UPR)monitors the folding of nascent polypeptides in the endoplasmic reticulum(ER)to alleviate cellular stress.However,the molecular mechanisms linking the UPR to endosperm development in plants remain poorly understood.In this study,we isolated and characterized a rice(Oryza sativa L.)mutant with defective endosperm development,designated as floury endosperm27(flo27).Molecular cloning revealed that FLO27 encodes RISBZ1/bZIP58,an endosperm-specific transcription factor co-expressed with seed storage protein(SSP)genes and starch biosynthesis-related genes in rice.The flo27 mutant exhibited severe ER stress,along with upregulation of UPR-related genes.Notably,RISBZ1 interacts with bZIP50 and bZIP60 to antagonistically suppress downstream UPR genes.These interactions simultaneously downregulate SSP and starch biosynthesis-related genes,ultimately leading to reduced dry matter accumulation.In conclusion,these findings demonstrate that RISBZ1 functions as a “brake signal” to mitigate ER stress,thus enhancing our understanding of the trade-off between grain filling and adaptation to adverse environmental conditions in rice.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
Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that te...Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that tetrapyrrole biosynthesis(TPB)and plastid gene expression(PGE)play essential roles in plastid retrograde signaling during early chloroplast biogenesis;however,their functional relationship remains unknown.In this study,we generated a series of rice TPB-related gun(genome uncoupled)mutants and systematically analyzed their effects on nuclear and plastid gene expression under normal conditions or when subjected to treatments with norflurazon(NF;a noncompetitive inhibitor of carotenoid biosynthesis)and/or lincomycin(Lin;a specific inhibitor of plastid translation).We show that under NF treatment,expression of plastid-encoded polymerase(PEP)-transcribed genes is significantly reduced in the wild type but is derepressed in the TPB-related gun mutants.We further demonstrate that the derepressed expression of PEPtranscribed genes may be caused by increased expression of the PEP core subunit and nuclear-encoded sigma factors and by elevated copy numbers of plastid genome per haploid genome.In addition,we show that expression of photosynthesis-associated nuclear genes(PhANGs)and PEP-transcribed genes is correlated in the rice TPB-related gun mutants,with or without NF or Lin treatment.A similar correlation between PhANGs and PGE is also observed in the Arabidopsis gun4 and gun5 mutants.Moreover,we show that increased expression of PEP-transcribed plastid genes is necessary for the gun phenotype in NF-treated TPB-related gun mutants.Further,we provide evidence that these TPB-related GUN genes act upstream of GUN1 in the regulation of retrograde signaling.Taken together,our results suggest that the TPB-related GUN genes control retrograde plastid signaling by regulating the PGE-dependent retrograde signaling pathway.展开更多
A series of nucleotide sugar interconversion enzymes(NSEs)generate the activated sugar donors required for biosynthesis of cell wall matrix polysaccharides and glycoproteins.UDPglucose 4-epimerases(UGEs)are NSEs that ...A series of nucleotide sugar interconversion enzymes(NSEs)generate the activated sugar donors required for biosynthesis of cell wall matrix polysaccharides and glycoproteins.UDPglucose 4-epimerases(UGEs)are NSEs that function in the interconversion of UDP-glucose(UDP-Glc)and UDP-galactose(UDP-Gal).The roles of UDP-glucose 4-epimerases in monocots remain unclear due to redundancy in the pathways.Here,we report a brittle plant(bp1)rice mutant that exhibits brittle leaves and culms at all growth stages.The mutant culms had reduced levels of rhamnogalacturonan I,homogalacturonan,and arabinogalactan proteins.Moreover,the mutant had altered contents of uronic acids,neutral noncellulosic monosaccharides,and cellulose.Map-based cloning demonstrated that OsBP1 encodes a UDPglucose 4-epimerase(OsUGE2),a cytosolic protein.We also show that BP1 can form homoand hetero-protein complexes with other UGE family members and with UDP-galactose transporters 2(OsUGT2)and 3(OsUGT3),which may facilitate the channeling of Gal to polysaccharides and proteoglycans.Our results demonstrate that BP1 participates in regulating the sugar composition and structure of rice cell walls.展开更多
This study examines the effects of different gloss types,namely LI textonly,L2 text-only,LI text plus picture,and L2 text plus picture on vocabulary retention in a multimedia reading environment.This investigation is ...This study examines the effects of different gloss types,namely LI textonly,L2 text-only,LI text plus picture,and L2 text plus picture on vocabulary retention in a multimedia reading environment.This investigation is based on the cognitive theory of multimedia learning and the revised hierarchical model with image.Sixteen participants read a computerized text under one of four gloss conditions and took an immediate and delayed vocabulary retention test.Quantitative analyses in this study were based on responses to a survey,and performance data drawn from the recognition and production tasks in the vocabulary retention test.Qualitative evidence was obtained through interviews with the participants regarding their attitudes to the use of multimedia glosses.Results of this study suggested that LI and L2 did not differ in terms of their effects on vocabulary retention.In addition,a combination of text and picture was more effective than text-only in sustaining recall of the glossed words.Survey and interview responses indicated the participants’mixed opinions about LI and L2 definitions and their strong preferences for pictures.The positive effect of L2 plus picture type glosses for long-term retention suggested the possible important role of mental involvement in the process of L2 vocabulary acquisition.展开更多
基金supported by the National Key Research and Development Program of China(2022YFD12000101)the Innovation Program of the Chinese Academy of Agricultural Sciences,the“JBGS”Project of Seed Industry Revitalization in Jiangsu Province(JBGS(2021)008)+2 种基金the Natural Science Foundation of Jiangsu(BK20240192)the Fundamental Research Funds for the Central Universities(KYT2024005 and KYZZ2024005)the earmarked fund for the China Agricultural Research System(CARS-01-05).
文摘In cereal crops,the endosperm synthesizes large quantities of proteins,including storage proteins and functional factors essential for the accumulation of storage reserves.The unfolded protein response(UPR)monitors the folding of nascent polypeptides in the endoplasmic reticulum(ER)to alleviate cellular stress.However,the molecular mechanisms linking the UPR to endosperm development in plants remain poorly understood.In this study,we isolated and characterized a rice(Oryza sativa L.)mutant with defective endosperm development,designated as floury endosperm27(flo27).Molecular cloning revealed that FLO27 encodes RISBZ1/bZIP58,an endosperm-specific transcription factor co-expressed with seed storage protein(SSP)genes and starch biosynthesis-related genes in rice.The flo27 mutant exhibited severe ER stress,along with upregulation of UPR-related genes.Notably,RISBZ1 interacts with bZIP50 and bZIP60 to antagonistically suppress downstream UPR genes.These interactions simultaneously downregulate SSP and starch biosynthesis-related genes,ultimately leading to reduced dry matter accumulation.In conclusion,these findings demonstrate that RISBZ1 functions as a “brake signal” to mitigate ER stress,thus enhancing our understanding of the trade-off between grain filling and adaptation to adverse environmental conditions in rice.
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supported by grants from the National Natural Science Foundation of China(91935301)National Natural Science Foundation of China Joint Program(U1701232)+4 种基金Jiangsu Science and Technology Development Program(BE2021360)Jiangsu Agricultural Science and Technology Innovation Fund Project(SCX(19)1079)Jiangsu Province Agriculture Independent Innovation Fund Project(CX(19)1002)National Key Research and Development Program of China(2016YFD0100903)the Fundamental Research Funds for the Central Universities(JCQY201902).
文摘Plastid-to-nucleus retrograde signaling coordinates nuclear gene expression with chloroplast developmental status and is essential for the photoautotrophic lifestyle of plants.Previous studies have established that tetrapyrrole biosynthesis(TPB)and plastid gene expression(PGE)play essential roles in plastid retrograde signaling during early chloroplast biogenesis;however,their functional relationship remains unknown.In this study,we generated a series of rice TPB-related gun(genome uncoupled)mutants and systematically analyzed their effects on nuclear and plastid gene expression under normal conditions or when subjected to treatments with norflurazon(NF;a noncompetitive inhibitor of carotenoid biosynthesis)and/or lincomycin(Lin;a specific inhibitor of plastid translation).We show that under NF treatment,expression of plastid-encoded polymerase(PEP)-transcribed genes is significantly reduced in the wild type but is derepressed in the TPB-related gun mutants.We further demonstrate that the derepressed expression of PEPtranscribed genes may be caused by increased expression of the PEP core subunit and nuclear-encoded sigma factors and by elevated copy numbers of plastid genome per haploid genome.In addition,we show that expression of photosynthesis-associated nuclear genes(PhANGs)and PEP-transcribed genes is correlated in the rice TPB-related gun mutants,with or without NF or Lin treatment.A similar correlation between PhANGs and PGE is also observed in the Arabidopsis gun4 and gun5 mutants.Moreover,we show that increased expression of PEP-transcribed plastid genes is necessary for the gun phenotype in NF-treated TPB-related gun mutants.Further,we provide evidence that these TPB-related GUN genes act upstream of GUN1 in the regulation of retrograde signaling.Taken together,our results suggest that the TPB-related GUN genes control retrograde plastid signaling by regulating the PGE-dependent retrograde signaling pathway.
基金supported by the Key Laboratory of Biology,Genetics and Breeding of Japonica Rice in the Mid-lower Yangtze River,Ministry of Agriculture,ChinaJiangsu Plant Gene Engineering Research Center+4 种基金Jiangsu Collaborative Innovation Center for Modern Crop Productionsupported by grants from the National Key R&D Program of China(2016YFD0101107)Jiangsu Science and Technology Development Program(BE2017368)Jiangsu Agricultural Science and Technology Innovation Fund Project(CX(16)1029)the Fundamental Research Funds for the Central Universities(KYTZ201601)。
文摘A series of nucleotide sugar interconversion enzymes(NSEs)generate the activated sugar donors required for biosynthesis of cell wall matrix polysaccharides and glycoproteins.UDPglucose 4-epimerases(UGEs)are NSEs that function in the interconversion of UDP-glucose(UDP-Glc)and UDP-galactose(UDP-Gal).The roles of UDP-glucose 4-epimerases in monocots remain unclear due to redundancy in the pathways.Here,we report a brittle plant(bp1)rice mutant that exhibits brittle leaves and culms at all growth stages.The mutant culms had reduced levels of rhamnogalacturonan I,homogalacturonan,and arabinogalactan proteins.Moreover,the mutant had altered contents of uronic acids,neutral noncellulosic monosaccharides,and cellulose.Map-based cloning demonstrated that OsBP1 encodes a UDPglucose 4-epimerase(OsUGE2),a cytosolic protein.We also show that BP1 can form homoand hetero-protein complexes with other UGE family members and with UDP-galactose transporters 2(OsUGT2)and 3(OsUGT3),which may facilitate the channeling of Gal to polysaccharides and proteoglycans.Our results demonstrate that BP1 participates in regulating the sugar composition and structure of rice cell walls.
文摘This study examines the effects of different gloss types,namely LI textonly,L2 text-only,LI text plus picture,and L2 text plus picture on vocabulary retention in a multimedia reading environment.This investigation is based on the cognitive theory of multimedia learning and the revised hierarchical model with image.Sixteen participants read a computerized text under one of four gloss conditions and took an immediate and delayed vocabulary retention test.Quantitative analyses in this study were based on responses to a survey,and performance data drawn from the recognition and production tasks in the vocabulary retention test.Qualitative evidence was obtained through interviews with the participants regarding their attitudes to the use of multimedia glosses.Results of this study suggested that LI and L2 did not differ in terms of their effects on vocabulary retention.In addition,a combination of text and picture was more effective than text-only in sustaining recall of the glossed words.Survey and interview responses indicated the participants’mixed opinions about LI and L2 definitions and their strong preferences for pictures.The positive effect of L2 plus picture type glosses for long-term retention suggested the possible important role of mental involvement in the process of L2 vocabulary acquisition.
