Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The s...Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms,the environment,and carbon cycling of temperate forest ecosystems under climate change.In this study,the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed,including an old volcano and a new volcano,which most recently erupted 300 years and 17-19×10^(5)years ago,respectively,and a non-volcano hills as control,based on space for time substitution and Miseq sequencing and bioinformation technology.The results showed that CH_(4) fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils.There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils.Methylococcus was the dominant genus in all soil samples.Additionally,the relative abundance of Methylococcus,along with Clonothrix,Methyloglobulus,Methylomagum,Methylomonas and Methylosarcina,were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils.The relative abundance of methanotroph belonging toγ-proteobacteria was significantly higher than that belonging toα-proteobacteria(P<0.05).Chao1,Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density,total porosity,p H,nitrate,dissolved organic carbon and dissolved organic nitrogen.There were significant differences in community structure between new-stage and old-stage volcanoes.Bulk density and p H are important soil properties contributing to the divergence of methanotrophs community structure,and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.展开更多
To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and ton...To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.展开更多
The mesocotyl,a structure located between the basal part of the seminal root and the coleoptile node of seedlings,contributes to pushing the shoot tip through the soil surface,a function that is essential for the unif...The mesocotyl,a structure located between the basal part of the seminal root and the coleoptile node of seedlings,contributes to pushing the shoot tip through the soil surface,a function that is essential for the uniform emergence of direct-seeded rice.Its elongation is inhibited by light and induced in darkness.This investigation of an indica rice(P25)with vigorous mesocotyl elongation was aimed at identifying the"omics"basis of its lightinduced growth inhibition.A transcriptomic comparison between mesocotyl tissues that had developed in the dark and then been exposed to light identified many differentially expressed genes(DEGs)and differentially abundant micro RNAs(mi RNAs).Degradome sequencing analysis revealed 27 negative mi RNA-target pairs.A co-expression regulatory network was constructed based on the mi RNAs,their corresponding targets,and DEGs with a common Gene Ontology term.It suggested that auxin and light,probably antagonistically,affect mesocotyl elongation by regulating polyamine oxidase activity.展开更多
Rice grain filling determines grain weight,final yield and grain quality.Here,a rice defective grain filling mutant,gif2,was identified.Grains of gif2 showed a slower filling rate and a significant lower final grain w...Rice grain filling determines grain weight,final yield and grain quality.Here,a rice defective grain filling mutant,gif2,was identified.Grains of gif2 showed a slower filling rate and a significant lower final grain weight and yield compared to wild-type.The starch content in gif2 was noticeably decreased and its physicochemical properties were also altered.Moreover,gif2 endosperm cells showed obvious defects in compound granule formation.Positional cloning identified GIF2 to encode an ADP-glucose pyrophosphorylase(AGP) large subunit,AGPL2;consequently,AGP enzyme activity in gif2 endosperms was remarkably decreased.GIF2 is mainly expressed in developing grains and the coded protein localizes in the cytosol.Yeast two hybrid assay showed that GIF2 interacted with AGP small subunits Os AGPS1,Os AGPS2a and Os AGPS2 b.Transcript levels for granule-bound starch synthase,starch synthase,starch branching enzyme and starch debranching enzyme were distinctly elevated in gif2 grains.In addition,the level of nucleotide diversity of the GIF2 locus was extremely low in both cultivated and wild rice.All of these results suggest that GIF2 plays important roles in the regulation of grain filling and starch biosynthesis during caryopsis development,and that it has been preserved during selection throughout domestication of modern rice.展开更多
Under conditions of labor or resource scarcity,direct seeding,rather than transplantation,is the preferred mode of rice(Oryza sativa)cultivation.This approach requires varieties that exhibit uniform seedling emergence...Under conditions of labor or resource scarcity,direct seeding,rather than transplantation,is the preferred mode of rice(Oryza sativa)cultivation.This approach requires varieties that exhibit uniform seedling emergence.Mesocotyl elongation(ME),the main driver of rapid emergence of rice seedlings from soil,is enhanced by darkness and inhibited by light.Plant polyamine oxidases(PAOs)oxidize polyamines(PAs)and release H2O2,Here,we established that OsPAO5 expression in rice seedlings is increased in the presence of light and inhibited by darkness.To determine its role in ME,we created OsPAO5 mutants using CRISPR/Cas9.Compared with the wild type,pao5 mutants had longer mesocotyls,released less H2O2,and synthesized more ethylene.The mutant seedlings emerged at a higher and more uniform rate,indicating their potential for use in direct seeding.Nucleotide polymorphism analysis revealed that an SNP(PAO5-578G/A)located 578 bp upstream of the OsPAO5 start codon alters its expression,and was selected during rice mesocotyl domestication.The PAO5-578G genotype conferring a long mesocotyl mainly exists in wild rice,most Aus accessions,and some Geng(Japonica)accessions.Intriguingly,knocking out OsPAO5 can remarkably increase the grain weight,grain number,and yield potential.In summary,we developed a novel strategy to obtain elite rice with higher emergence vigor and yield potential,which can be conveniently and widely used to breed varieties of direct-seeding rice.展开更多
The percentage of amylose in the endosperm of rice(Oryza sativa)largely determines grain cooking and eating qualities.Granule-bound starch synthase I(GBSSI)and GBSSII are responsible for amylose biosynthesis in the en...The percentage of amylose in the endosperm of rice(Oryza sativa)largely determines grain cooking and eating qualities.Granule-bound starch synthase I(GBSSI)and GBSSII are responsible for amylose biosynthesis in the endosperm and leaf,respectively.Here,we identified OsGBP,a rice GBSS-binding protein that interacted with GBSSI and GBSSII in vitro and in vivo.The total starch and amylose contents in osgbp mutants were significantly lower than those of wild type in leaves and grains,resulting in reduced grain weight and quality.The carbohydrate-binding module 48(CBM48)domain present in the C-terminus of OsGBP is crucial for OsGBP binding to starch.In the osgbp mutant,the extent of GBSSI and GBSSII binding to starch in the leaf and endospermwas significantly lower than wild type.Our data suggest that OsGBP plays an important role in leaf and endosperm starch biosynthesis by mediating the binding of GBSS proteins to developing starch granules.This elucidation of the function of OsGBP enhances our understanding of the molecular basis of starch biosyn-thesis in rice and contributes information that can be potentially used for the genetic improvement of yield and grain quality.展开更多
Pentatricopeptide repeat(PPR)proteins play important roles in the post-transcriptional modification of organellar RNAs in plants.However,the function of most PPR proteins remains unknown.Here,we characterized the rice...Pentatricopeptide repeat(PPR)proteins play important roles in the post-transcriptional modification of organellar RNAs in plants.However,the function of most PPR proteins remains unknown.Here,we characterized the rice(Oryza sativa L.)chlorophyll deficient 4(cde4)mutant which exhibits an albino phenotype during early leaf development,with decreased chlorophyll contents and abnormal chloroplasts at low-temperature(20℃).Positional cloning revealed that CDE4 encodes a P-type PPR protein localized in chloroplasts.In the cde4 mutant,plastid-encoded polymerase(PEP)-dependent transcript levels were significantly reduced,but transcript levels of nuclear-encoded genes were increased compared to wild-type plants at 20℃.CDE4 directly binds to the transcripts of the chloroplast genes rpl2,ndhA,and ndhB.Intron splicing of these transcripts was defective in the cde4 mutant at 20℃,but was normal at 32℃.Moreover,CDE4 interacts with the guanylate kinase VIRESCENT 2(V2);overexpression of V2 enhanced CDE4 protein stability,thereby rescuing the cde4 phenotype at 20℃.Our results suggest that CDE4 participates in plastid RNA splicing and plays an important role in rice chloroplast development under lowtemperature conditions.展开更多
基金the Special Projects for the Central Government to guide the development of local science and technology(ZY20B15)the Key Research&Development Program funding project of Heilongjiang Province(GA21C030)the Research Funds of Provincial Research Institutes of Heilongjiang Province(ZNBZ2022ZR07)。
文摘Methanotrophs,organisms that obtain oxygen by oxidizing methane,are recognized as the only known biological sink for atmospheric CH_4,and forest soil methanotrophs play crucial roles in mitigating global warming.The succession patterns of methanotrophic communities and functions in Wudalianchi volcano forest soils could provide a basis for the study of evolutionary mechanisms between soil microorganisms,the environment,and carbon cycling of temperate forest ecosystems under climate change.In this study,the characteristics and drivers of methanotrophic community structure and function of two volcanic soils at different stages of development are analyzed,including an old volcano and a new volcano,which most recently erupted 300 years and 17-19×10^(5)years ago,respectively,and a non-volcano hills as control,based on space for time substitution and Miseq sequencing and bioinformation technology.The results showed that CH_(4) fluxes were significantly higher in old-stage volcano forest soils than new-stage forest soils and non-volcano forest soils.There were significant differences in the community composition and diversity of soil methanotrophs from different volcano forest soils.Methylococcus was the dominant genus in all soil samples.Additionally,the relative abundance of Methylococcus,along with Clonothrix,Methyloglobulus,Methylomagum,Methylomonas and Methylosarcina,were the important genera responsible for the differences in methanotrophic community structure in different volcano forest soils.The relative abundance of methanotroph belonging toγ-proteobacteria was significantly higher than that belonging toα-proteobacteria(P<0.05).Chao1,Shannon and Simpson indices of soil methanotrophic community were significantly lower in new-stage volcanos and were significantly affected by bulk density,total porosity,p H,nitrate,dissolved organic carbon and dissolved organic nitrogen.There were significant differences in community structure between new-stage and old-stage volcanoes.Bulk density and p H are important soil properties contributing to the divergence of methanotrophs community structure,and changes in soil properties due to soil development time are important factors driving differences in methanotrophs communities in Wudalianchi volcanic soils.
基金supported by Natural Science Foundation of China[grant numbers 81760188]Scientific Research Fund of Guangxi Provincial Education Department [grant numbers 2017KY0103 (02601217023C)]
文摘To characterize the patterns of ABR waves in tree shrews, we must understand the hearing sensitivity and auditory function of healthy adult tree shrews. Fifteen tree shrews(30 ears) were stimulated with clicks and tone-pips at 11 different frequencies from 1 to 60 kHz. The ABR waves were recorded and analyzed. The ABR consisted of five to seven positive waves in the first 10 ms after a click stimulus, and the average hearing threshold of component III was 27.86 ± 3.78 dB SPL. Wave III was the largest and most clear. The ABR threshold was related to the tone-pip sitmulus by a "U" shaped curve. The sensitive frequency was approximately 8 kHz in tree shrews. The latencies systematically decreased with increasing stimulus frequencies. The ABR amplitudes of wave III increased as the sound pressure level increased. All of these results provide an empirical basis for future studies of hearing diseases in tree shrews.
基金financially supported by the National S&T Major Project of China(2016ZX08001006)the National Key Research and Development Program of China(2016YFD0101801 and 2017YFD0100300)the Agricultural Science and Technology Innovation Program of CAAS。
文摘The mesocotyl,a structure located between the basal part of the seminal root and the coleoptile node of seedlings,contributes to pushing the shoot tip through the soil surface,a function that is essential for the uniform emergence of direct-seeded rice.Its elongation is inhibited by light and induced in darkness.This investigation of an indica rice(P25)with vigorous mesocotyl elongation was aimed at identifying the"omics"basis of its lightinduced growth inhibition.A transcriptomic comparison between mesocotyl tissues that had developed in the dark and then been exposed to light identified many differentially expressed genes(DEGs)and differentially abundant micro RNAs(mi RNAs).Degradome sequencing analysis revealed 27 negative mi RNA-target pairs.A co-expression regulatory network was constructed based on the mi RNAs,their corresponding targets,and DEGs with a common Gene Ontology term.It suggested that auxin and light,probably antagonistically,affect mesocotyl elongation by regulating polyamine oxidase activity.
基金supported by the Natural Science Foundation of China(grants No.31161140348,31471472,31301303,31161140348)by the National S&T Major Project (2014ZX08001006,2016ZX08001006)
文摘Rice grain filling determines grain weight,final yield and grain quality.Here,a rice defective grain filling mutant,gif2,was identified.Grains of gif2 showed a slower filling rate and a significant lower final grain weight and yield compared to wild-type.The starch content in gif2 was noticeably decreased and its physicochemical properties were also altered.Moreover,gif2 endosperm cells showed obvious defects in compound granule formation.Positional cloning identified GIF2 to encode an ADP-glucose pyrophosphorylase(AGP) large subunit,AGPL2;consequently,AGP enzyme activity in gif2 endosperms was remarkably decreased.GIF2 is mainly expressed in developing grains and the coded protein localizes in the cytosol.Yeast two hybrid assay showed that GIF2 interacted with AGP small subunits Os AGPS1,Os AGPS2a and Os AGPS2 b.Transcript levels for granule-bound starch synthase,starch synthase,starch branching enzyme and starch debranching enzyme were distinctly elevated in gif2 grains.In addition,the level of nucleotide diversity of the GIF2 locus was extremely low in both cultivated and wild rice.All of these results suggest that GIF2 plays important roles in the regulation of grain filling and starch biosynthesis during caryopsis development,and that it has been preserved during selection throughout domestication of modern rice.
基金This work was supported by the National Key Research and Development Program of China(2017YFD0100300 and 2016YFD0101801)the Central Public-interest Scientific Institution Basal Research Fund of China(Y2020YJ09 and Y2020PT07)Agricultural Sciences and Technologies Innovation Program of the Chinese Academy of Agricultural Sciences.
文摘Under conditions of labor or resource scarcity,direct seeding,rather than transplantation,is the preferred mode of rice(Oryza sativa)cultivation.This approach requires varieties that exhibit uniform seedling emergence.Mesocotyl elongation(ME),the main driver of rapid emergence of rice seedlings from soil,is enhanced by darkness and inhibited by light.Plant polyamine oxidases(PAOs)oxidize polyamines(PAs)and release H2O2,Here,we established that OsPAO5 expression in rice seedlings is increased in the presence of light and inhibited by darkness.To determine its role in ME,we created OsPAO5 mutants using CRISPR/Cas9.Compared with the wild type,pao5 mutants had longer mesocotyls,released less H2O2,and synthesized more ethylene.The mutant seedlings emerged at a higher and more uniform rate,indicating their potential for use in direct seeding.Nucleotide polymorphism analysis revealed that an SNP(PAO5-578G/A)located 578 bp upstream of the OsPAO5 start codon alters its expression,and was selected during rice mesocotyl domestication.The PAO5-578G genotype conferring a long mesocotyl mainly exists in wild rice,most Aus accessions,and some Geng(Japonica)accessions.Intriguingly,knocking out OsPAO5 can remarkably increase the grain weight,grain number,and yield potential.In summary,we developed a novel strategy to obtain elite rice with higher emergence vigor and yield potential,which can be conveniently and widely used to breed varieties of direct-seeding rice.
基金This work was supported by the National S&T Major Project of China(2016ZX08001006,2016ZX08001001)the National Natural Science Foundation of China(31971925)Agricultural Sciences and Technologies Innovation Program of Chinese Academy of(Agricultural Sciences(CAAS).
文摘The percentage of amylose in the endosperm of rice(Oryza sativa)largely determines grain cooking and eating qualities.Granule-bound starch synthase I(GBSSI)and GBSSII are responsible for amylose biosynthesis in the endosperm and leaf,respectively.Here,we identified OsGBP,a rice GBSS-binding protein that interacted with GBSSI and GBSSII in vitro and in vivo.The total starch and amylose contents in osgbp mutants were significantly lower than those of wild type in leaves and grains,resulting in reduced grain weight and quality.The carbohydrate-binding module 48(CBM48)domain present in the C-terminus of OsGBP is crucial for OsGBP binding to starch.In the osgbp mutant,the extent of GBSSI and GBSSII binding to starch in the leaf and endospermwas significantly lower than wild type.Our data suggest that OsGBP plays an important role in leaf and endosperm starch biosynthesis by mediating the binding of GBSS proteins to developing starch granules.This elucidation of the function of OsGBP enhances our understanding of the molecular basis of starch biosyn-thesis in rice and contributes information that can be potentially used for the genetic improvement of yield and grain quality.
基金This work was supported by the Natural Science Foundation of Zhejiang province(LR20C13002)the special support plan for high level talents in Zhejiang Province(2019R52032)Agricultural Sciences and Technologies Innovation Program of the Chinese Academy of Agricultural Sciences.
文摘Pentatricopeptide repeat(PPR)proteins play important roles in the post-transcriptional modification of organellar RNAs in plants.However,the function of most PPR proteins remains unknown.Here,we characterized the rice(Oryza sativa L.)chlorophyll deficient 4(cde4)mutant which exhibits an albino phenotype during early leaf development,with decreased chlorophyll contents and abnormal chloroplasts at low-temperature(20℃).Positional cloning revealed that CDE4 encodes a P-type PPR protein localized in chloroplasts.In the cde4 mutant,plastid-encoded polymerase(PEP)-dependent transcript levels were significantly reduced,but transcript levels of nuclear-encoded genes were increased compared to wild-type plants at 20℃.CDE4 directly binds to the transcripts of the chloroplast genes rpl2,ndhA,and ndhB.Intron splicing of these transcripts was defective in the cde4 mutant at 20℃,but was normal at 32℃.Moreover,CDE4 interacts with the guanylate kinase VIRESCENT 2(V2);overexpression of V2 enhanced CDE4 protein stability,thereby rescuing the cde4 phenotype at 20℃.Our results suggest that CDE4 participates in plastid RNA splicing and plays an important role in rice chloroplast development under lowtemperature conditions.
