Background:Fat deposition is an important economic consideration in pig production.The amount of fat deposition in pigs seriously affects production efficiency,quality,and reproductive performance,while also affecting...Background:Fat deposition is an important economic consideration in pig production.The amount of fat deposition in pigs seriously affects production efficiency,quality,and reproductive performance,while also affecting consumers’choice of pork.Weighted gene co-expression network analysis(WGCNA)is effective in pig genetic studies.Therefore,this study aimed to identify modules that co-express genes associated with fat deposition in pigs(Songliao black and Landrace breeds)with extreme levels of backfat(high and low)and to identify the core genes in each of these modules.Results:We used RNA sequences generated in different pig tissues to construct a gene expression matrix consisting of 12,862 genes from 36 samples.Eleven co-expression modules were identified using WGCNA and the number of genes in these modules ranged from 39 to 3,363.Four co-expression modules were significantly correlated with backfat thickness.A total of 16 genes(RAD9A,IGF2R,SCAP,TCAP,SMYD1,PFKM,DGAT1,GPS2,IGF1,MAPK8,FABP,FABP5,LEPR,UCP3,APOF,and FASN)were associated with fat deposition.Conclusions:RAD9A,TCAP,SMYD1,PFKM,GPS2,and APOF were the key genes in the four modules based on the degree of gene connectivity.Combining these results with those from differential gene analysis,SMYD1 and PFKM were proposed as strong candidate genes for body size traits.This study explored the key genes that regulate porcine fat deposition and lays the foundation for further research into the molecular regulatory mechanisms underlying porcine fat deposition.展开更多
Chronic prostatitis(CP)/chronic pelvic-pain syndrome(CPPS)is a common urinary-system disease with a high incidence in young and middle-aged men,seriously affecting patients'ability to work and their quality of lif...Chronic prostatitis(CP)/chronic pelvic-pain syndrome(CPPS)is a common urinary-system disease with a high incidence in young and middle-aged men,seriously affecting patients'ability to work and their quality of life(Qo L).Western medicine(WM)has some limitations in treating CP/CPPS.Acupuncture is an ancient Chinese medical method that is commonly used to treat this condition and has a relatively good effect on it.Many randomized controlled trials(RCTs)on this subject have been published.For this study,we searched the China National Knowledge Infrastructure(CNKI),Chinese Science and Technology Periodical(VIP),Wanfang,Sino Med,and Pub Med databases for RCTs on acupuncture treatment of CP/CPPS in the last 5 years(2016/01/01-2021/12/01).In addition,we conducted analysis and research,aiming to summarize acupuncture treatment in CP/CPPS RCTs and the clinical efficacy,with the goal of providing clinical reference.A total of 466 related documents were retrieved in the search,and 62 articles were retained after screening.We obtained RCT information on acupuncture treatment of CP/CPPS.The results showed that several relevant clinical studies have been performed over the last 5 years and that acupuncture and moxibustion have better curative effect on CP/CPPS than WM.Due to the small number of included studies,more experimental evidence is needed to verify the clinical efficacy of acupuncture.展开更多
Arginine catabolism involves enzyme-dependent reactions in both mitochondria and the cytosol,defects in which may lead to hyperargininemia,a devastating developmental disorder.It is largely unknown if defective argini...Arginine catabolism involves enzyme-dependent reactions in both mitochondria and the cytosol,defects in which may lead to hyperargininemia,a devastating developmental disorder.It is largely unknown if defective arginine catabolism has any effects on mitochondria.Here we report that normal arginine catabolism is essential for mitochondrial homeostasis in Caenorhabditis elegans.Mutations of the arginase gene argn-1 lead to abnormal mitochondrial enlargement and reduced adenosine triphosphate(ATP)production in C elegans hypodermal cells.ARGN-1 localizes to mitochondria and its loss causes arginine accumulation,which disrupts mitochondrial dynamics.Heterologous expression of human ARGl or ARG2 rescued the mitochondrial defects of argn-1 mutants.Importantly,genetic inactivation of the mitochondrial basic amino acid transporter SLC-25A29 or the mitochondrial glutamate transporter SLC-25A18.1 fully suppressed the mitochondrial defects caused by argn-1 mutations.These findings suggest that mitochondrial damage probably contributes to the pathogenesis of hyperargininemia and provide clues for developing therapeutic treatments for hyperargininemia.展开更多
China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a ...China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon（LFOC） storage increased by 221 g C/m2（84%） and the total soil organic carbon（SOC） storage increased by 435 g C/m2（55%）.The light fraction dry matter content represented a small proportion of the total soil mass（ranging from 0.74% in 2005 to 1.39% in 2013）,but the proportion of total SOC storage accounted for by LFOC was remarkable（ranging from 33% to 40%）.The C sequestration averaged 28 g C/（m2·a） for LFOC and 54 g C/（m2·a） for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt＋clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land.展开更多
Nitrogen is an essential macronutrient for all living organisms and is critical for crop productivity and quality.In higher plants,inorganic nitrogen is absorbed through roots and then assimilated into amino acids by ...Nitrogen is an essential macronutrient for all living organisms and is critical for crop productivity and quality.In higher plants,inorganic nitrogen is absorbed through roots and then assimilated into amino acids by the highly conserved glutamine synthetase/glutamine:2-oxoglutarate aminotransferase(GS/GOGAT)cycle.How nitrogen metabolism and nitrogen starvation responses of plants are regulated remains largely unknown.Previous studies revealed that mutations in the rice ABNORMAL CYTOKININ RESPONSE1(ABC1)gene encoding Fd-GOGAT cause a typical nitrogen deficiency syndrome.Here,we show that ARE2(for ABC1 REPRESSOR2)is a key regulator of nitrogen starvation responses in rice.The are2 mutations partially rescue the nitrogen-deficient phenotype of abc1 and the are2 mutants show enhanced tolerance to nitrogen deficiency,suggesting that ARE2 genetically interacts with ABC1/Fd-GOGAT.ARE2 encodes a chloroplast-localized Rel A/Spo T homolog protein that catalyzes the hydrolysis of guanosine pentaphosphate or tetraphosphate(p)pp Gpp,an alarmone regulating the stringent response in bacteria under nutritional stress conditions.The are2 mutants accumulate excessive amounts of(p)pp Gpp,which correlate with lower levels of photosynthetic proteins and higher amino acid levels.Collectively,these observations suggest that the alarmone(p)pp Gpp mediates nitrogen stress responses and may constitute a highly conserved mechanism from bacteria to plants.展开更多
In this study, we analyze factors affecting the explosion limits of flammable refrigerants. We conclude that any method used for measuring flammable refrigerant explosion limits has its conditional restrictions. Flamm...In this study, we analyze factors affecting the explosion limits of flammable refrigerants. We conclude that any method used for measuring flammable refrigerant explosion limits has its conditional restrictions. Flammable refrigerants in the atmosphere can also explode under certain conditions, when the concentration is approaching the explosion limits. An experimental study on the explosion limits of six kinds of flammable refrigerants is carried out with a mixture of refrigerant and combustible refrigerant, which has a similar effect to a flame retardant. An experimental apparatus was designed to test the explosion limits of mixtures made from three different nonflammable refrigerants and six different flammable refrigerants. Two practical models were developed to estimate the critical concentration for inhibiting explosion of refrigerant mixtures: one was made up of two flammable components with one nonflammable component, and the second was made up of one flammable component with two nonflammable components.展开更多
Plants assimilate inorganic nitrogen absorbed from soil into organic forms as Gin and Glu through the glutamine synthetase/glutamine：2-oxoglutarate amidotransferase （GS/GOGAT） cycle. Whereas GS cata- lyzes the form...Plants assimilate inorganic nitrogen absorbed from soil into organic forms as Gin and Glu through the glutamine synthetase/glutamine：2-oxoglutarate amidotransferase （GS/GOGAT） cycle. Whereas GS cata- lyzes the formation of Gin from Glu and ammonia, GOGAT catalyzes the transfer of an amide group from Gin to 2-oxoglutarate to produce two molecules of Glu. However, the regulatory role of the GS/GOGAT cycle in the carbon-nitrogen balance is not well understood. Here, we report the functional characterization of rice ABNORMAL CYTOKININ RESPONSE 1 （ABC1） gene that encodes a ferredoxin-dependent （Fd）- GOGAT. The weak mutant allele abcl-1 mutant shows a typical nitrogen-deficient syndrome, whereas the T-DNA insertional mutant abcl-2 is seedling lethal. Metabolomics analysis revealed the accumulation of an excessive amount of amino acids with high N/C ratio （Gin and Asn） and several intermediates in the tricarboxylic acid cycle in abcl-1, suggesting that ABC1 plays a critical role in nitrogen assimilation and carbon-nitrogen balance. Five non-synonymous single-nucleotide polymorphisms were identified in the ABC1 coding region and characterized as three distinct haplotypes, which have been highly and specifically differentiated between japonica and indica subspecies. Collectively, these results suggest that ABC1/ OsFd-GOGAT is essential for plant growth and development by modulating nitrogen assimilation and the carbon-nitrogen balance.展开更多
Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essentia...Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essential for plant survival in natural environments.A growing appreciation of microbiota for plant health is fuelling rapid advances in genetic mechanisms of controlling microbiota by host plants.PSMs have long been proposed to mediate plant and single microbe interactions.However,the effects of PSMs,especially those evolutionarily new PSMs,on root microbiota at community level remain to be elucidated.Here,we discovered sesterterpenes in Arabidopsis thaliana,produced by recently duplicated prenyltransferase-terpene synthase(PT-TPS) gene clusters,with neo-functionalization.A single-residue substitution played a critical role in the acquisition of sesterterpene synthase(sesterTPS) activity in Brassicaceae plants.Moreover,we found that the absence of two root-specific sesterterpenoids,with similar chemical structure,significantly affected root microbiota assembly in similar patterns.Our results not only demonstrate the sensitivity of plant microbiota to PSMs but also establish a complete framework of host plants to control root microbiota composition through evolutionarily dynamic PSMs.展开更多
Bird predation during seed maturation causes great loss to agricultural production.In this study,through GWAS analysis of a large-scale sorghum germplasm diversity panel,we identified that Tannin1,which encodes a WD40...Bird predation during seed maturation causes great loss to agricultural production.In this study,through GWAS analysis of a large-scale sorghum germplasm diversity panel,we identified that Tannin1,which encodes a WD40 protein functioning in the WD40/MYB/bHLH complex,controls bird feeding behavior in sorghum.Metabolic profiling analysis showed that a group of sorghum accessions preferred by birds contain mutated tan1-a/b alleles and accumulate significantly lower levels of anthocyanins and condensed tannin compounds.In contrast,a variety of aromatic and fatty acid-derived volatiles accumulate at significantly higher levels in these bird-preference accessions.We subsequently conducted both sparrow feeding and sparrow volatile attractant assays,which confirmed,respectively,the antifeedant and attractant functions of these differentially accumulated metabolites.In addition,the connection between the biosynthesis pathway of anthocyanin and proanthocyanidin and the pathway of fatty acid–derived volatile biosynthesis was demonstrated by discovering that Tannin1 complex modulates fatty acid biosynthesis by regulating the expression of SbGL2 in sorghum,thus affecting the accumulation of fatty acid-derived volatiles.Taken together,our study identified Tannin1 as the gene underlying the major locus controlling bird feeding behavior in sorghum,illustrating an example of the identification of an ecologically impactful molecular mechanism from field observation and providing significant insights into the chemistry of bird–plant ecological interactions.展开更多
Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop （Humulus lupulus） glandular trichomes. Branched short-chain acyI-CoAs （e.g. isobutyry...Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop （Humulus lupulus） glandular trichomes. Branched short-chain acyI-CoAs （e.g. isobutyryI-CoA, isovaleryl- CoA and 2-methylbutyryI-CoA）, derived from the degradation of branched-chain amino acids （BCAAs）, are essential building blocks for the biosynthesis of bitter acids in hops. However, little is known regarding what components are needed to produce and maintain the pool of branched short-chain acyI-CoAs in hop trichomes. Here, we present several lines of evidence that both CoA ligases and thioesterases are likely involved in bitter acid biosynthesis. Recombinant HICCL2 （carboxyl CoA ligase） protein had high specific activity for isovaleric acid as a substrate （Kcat/Km = 4100 s-~ M-l）, whereas recombinant HICCL4 specifically utilized isobutyric acid （Kcat/Km = 1800 s-1 M-1） and 2-methylbutyric acid （Kcat/ Km = 6900 s-1 M-~） as substrates. Both HICCLs, like hop valerophenone synthase （HIVPS）, were expressed strongly in glandular trichomes and localized to the cytoplasm. Co-expression of HICCL2 and HICCL4 with HIVPS in yeast led to significant production of acylphloroglucinols （the direct precursors for bitter acid biosynthesis）, which further confirmed the biochemical function of these two HICCLs in vivo. Functional identification of a thioesterase that catalyzed the reverse reaction of CCLs in mitochondria, together with the comprehensive analysis of genes involved BCAA catabolism, supported the idea that cytosolic CoA ligases are required for linking BCAA degradation and bitter acid biosynthesis in glandular trichomes. The evolution and other possible physiological roles of branched short-chain fatty acid：CoA ligases in planta are also discussed.展开更多
Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-ci...Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-cies of NA conjugates, which are mainly involved in NA detoxification, were also found in all tested land plants. Among these conjugates, MeNA （NA methyl ester） has been widely detected in angiosperm plants, although its physiological function and the underlying mechanism for its production in planta remain largely unknown. Here, we show that MeNA is an NAD precursor undergoing more efficient long-distance trans-port between organs than NA and nicotinamide in Arabidopsis. We found that Arabidopsis has one meth- yltransferase （designated AtNaMT1） capable of catalyzing carboxyl methylation of NA to yield MeNA and one methyl esterase （MES2） predominantly hydrolyzing MeNA back to NA. We further uncovered that the transfer of [^14C]MeNA from the root to leaf was significantly increased in both MES2 knockdown and NaMTl-overexpressing lines, suggesting that both NaMT1 and MES2 fine-tune the long-distance transport of MeNA, which is ultimately utilized for NAD production. Abiotic stress （salt, abscisic acid, and mannitol） treatments, which are known to exacerbate NAD degradation, induce the expression of NaMT1 but sup-press MES2 expression, suggesting that MeNA may play a role in stress adaption. Collectively, our study indicates that reversible methylation of NA controls the biosynthesis of MeNA in Arabidopsis, which pre-sumably functions as a detoxification form of free NA for efficient long-distance transport and eventually NAD production especially under abiotic stress, providing new insights into the relationship between NAD biosynthesis and NA conjugation in plants.展开更多
Terpenes are the largest and most diverse class of plant specialized metabolites.Sesterterpenes(C25),which are derived from the plastid methylerythritol phosphate pathway,were recently characterized in plants.In Arabi...Terpenes are the largest and most diverse class of plant specialized metabolites.Sesterterpenes(C25),which are derived from the plastid methylerythritol phosphate pathway,were recently characterized in plants.In Arabidopsis thaliana,four genes encoding geranylfarnesyl diphosphate synthase(GFPPS)(AtGFPPS1 to 4)are responsible for the production of GFPP,which is the common precursor for sesterterpene biosynthesis.However,the interplay between sesterterpenes and other known terpenes remain elusive.Here,we first provide genetic evidence to demonstrate that GFPPSs are responsible for sesterterpene production in Arabidopsis.Blockage of the sesterterpene pathway at the GFPPS step increased the production of geranylgeranyl diphosphate(GGPP)-derived terpenes.Interestingly,co-expression of sester TPSs in GFPPSOE(overexpression)plants rescued the phenotypic changes of GFPPS-OE plants by restoring the endogenous GGPP.We further demonstrated that,in addition to precursor(DMAPP/IPP)competition by GFPPS and GGPP synthase(GGPPS)in plastids,GFPPS directly decreased the activity of GGPPS through protein-protein interaction,ultimately leading to GGPP deficiency in planta.Our study provides a new regulatory mechanism of the plastidial terpenoid network in plant cells.展开更多
基金financially supported by the National Key Research and Development Project(2019YFE0106800)the National Key R&D Program of China(2018YFD0501000)+2 种基金Beijing Municipal Education Commission Science and Technology Program General Project(KM201910020010)Beijing Innovation Consortium of Agriculture Research System(BAIC02-2021)the China Agriculture Research System(CARS-35).
文摘Background:Fat deposition is an important economic consideration in pig production.The amount of fat deposition in pigs seriously affects production efficiency,quality,and reproductive performance,while also affecting consumers’choice of pork.Weighted gene co-expression network analysis(WGCNA)is effective in pig genetic studies.Therefore,this study aimed to identify modules that co-express genes associated with fat deposition in pigs(Songliao black and Landrace breeds)with extreme levels of backfat(high and low)and to identify the core genes in each of these modules.Results:We used RNA sequences generated in different pig tissues to construct a gene expression matrix consisting of 12,862 genes from 36 samples.Eleven co-expression modules were identified using WGCNA and the number of genes in these modules ranged from 39 to 3,363.Four co-expression modules were significantly correlated with backfat thickness.A total of 16 genes(RAD9A,IGF2R,SCAP,TCAP,SMYD1,PFKM,DGAT1,GPS2,IGF1,MAPK8,FABP,FABP5,LEPR,UCP3,APOF,and FASN)were associated with fat deposition.Conclusions:RAD9A,TCAP,SMYD1,PFKM,GPS2,and APOF were the key genes in the four modules based on the degree of gene connectivity.Combining these results with those from differential gene analysis,SMYD1 and PFKM were proposed as strong candidate genes for body size traits.This study explored the key genes that regulate porcine fat deposition and lays the foundation for further research into the molecular regulatory mechanisms underlying porcine fat deposition.
基金funded by the Research on the Collation and Excavation of the Folk Characteristic Diagnosis and Treatment Technology of Cerebral Palsy,the Dominant Disease of Traditional Chinese Medicine(ZZ140516)。
文摘Chronic prostatitis(CP)/chronic pelvic-pain syndrome(CPPS)is a common urinary-system disease with a high incidence in young and middle-aged men,seriously affecting patients'ability to work and their quality of life(Qo L).Western medicine(WM)has some limitations in treating CP/CPPS.Acupuncture is an ancient Chinese medical method that is commonly used to treat this condition and has a relatively good effect on it.Many randomized controlled trials(RCTs)on this subject have been published.For this study,we searched the China National Knowledge Infrastructure(CNKI),Chinese Science and Technology Periodical(VIP),Wanfang,Sino Med,and Pub Med databases for RCTs on acupuncture treatment of CP/CPPS in the last 5 years(2016/01/01-2021/12/01).In addition,we conducted analysis and research,aiming to summarize acupuncture treatment in CP/CPPS RCTs and the clinical efficacy,with the goal of providing clinical reference.A total of 466 related documents were retrieved in the search,and 62 articles were retained after screening.We obtained RCT information on acupuncture treatment of CP/CPPS.The results showed that several relevant clinical studies have been performed over the last 5 years and that acupuncture and moxibustion have better curative effect on CP/CPPS than WM.Due to the small number of included studies,more experimental evidence is needed to verify the clinical efficacy of acupuncture.
基金supported by grants from the National Scicnce Foundation of China(91954204 and 31730053)the National Basic Research Program of China(2017YFA0503403)。
文摘Arginine catabolism involves enzyme-dependent reactions in both mitochondria and the cytosol,defects in which may lead to hyperargininemia,a devastating developmental disorder.It is largely unknown if defective arginine catabolism has any effects on mitochondria.Here we report that normal arginine catabolism is essential for mitochondrial homeostasis in Caenorhabditis elegans.Mutations of the arginase gene argn-1 lead to abnormal mitochondrial enlargement and reduced adenosine triphosphate(ATP)production in C elegans hypodermal cells.ARGN-1 localizes to mitochondria and its loss causes arginine accumulation,which disrupts mitochondrial dynamics.Heterologous expression of human ARGl or ARG2 rescued the mitochondrial defects of argn-1 mutants.Importantly,genetic inactivation of the mitochondrial basic amino acid transporter SLC-25A29 or the mitochondrial glutamate transporter SLC-25A18.1 fully suppressed the mitochondrial defects caused by argn-1 mutations.These findings suggest that mitochondrial damage probably contributes to the pathogenesis of hyperargininemia and provide clues for developing therapeutic treatments for hyperargininemia.
基金supported by the National Natural Science Foundation of China (41271007,31170413)the National Science and Technology Support Program of China (2011BAC07B02)
文摘China＇s Horqin Sandy Land,a formerly lush grassland,has experienced extensive desertification that caused considerable carbon（C） losses from the plant-soil system.Natural restoration through grazing exclusion is a widely suggested option to sequester C and to restore degraded land.In a desertified grassland,we investigated the C accumulation in the total and light fractions of the soil organic matter from 2005 to 2013 during natural restoration.To a depth of 20 cm,the light fraction organic carbon（LFOC） storage increased by 221 g C/m2（84%） and the total soil organic carbon（SOC） storage increased by 435 g C/m2（55%）.The light fraction dry matter content represented a small proportion of the total soil mass（ranging from 0.74% in 2005 to 1.39% in 2013）,but the proportion of total SOC storage accounted for by LFOC was remarkable（ranging from 33% to 40%）.The C sequestration averaged 28 g C/（m2·a） for LFOC and 54 g C/（m2·a） for total SOC.The total SOC was strongly and significantly positively linearly related to the light fraction dry matter content and the proportions of fine sand and silt＋clay.The light fraction organic matter played a major role in total SOC sequestration.Our results suggest that grazing exclusion can restore desertified grassland and has a high potential for sequestering SOC in the semiarid Horqin Sandy Land.
基金supported by grants from the Ministry of Agriculture and Rural Affairs of China(2016ZX08009003-0022016ZX08009003-005 and 2016ZX08009003-004)+2 种基金Chinese Academy of Sciences(XDA08010401-2)the Ministry of Science and Technology of the People’s Republic of China(2016YFD0100706)the State Key Laboratory of Plant Genomics。
文摘Nitrogen is an essential macronutrient for all living organisms and is critical for crop productivity and quality.In higher plants,inorganic nitrogen is absorbed through roots and then assimilated into amino acids by the highly conserved glutamine synthetase/glutamine:2-oxoglutarate aminotransferase(GS/GOGAT)cycle.How nitrogen metabolism and nitrogen starvation responses of plants are regulated remains largely unknown.Previous studies revealed that mutations in the rice ABNORMAL CYTOKININ RESPONSE1(ABC1)gene encoding Fd-GOGAT cause a typical nitrogen deficiency syndrome.Here,we show that ARE2(for ABC1 REPRESSOR2)is a key regulator of nitrogen starvation responses in rice.The are2 mutations partially rescue the nitrogen-deficient phenotype of abc1 and the are2 mutants show enhanced tolerance to nitrogen deficiency,suggesting that ARE2 genetically interacts with ABC1/Fd-GOGAT.ARE2 encodes a chloroplast-localized Rel A/Spo T homolog protein that catalyzes the hydrolysis of guanosine pentaphosphate or tetraphosphate(p)pp Gpp,an alarmone regulating the stringent response in bacteria under nutritional stress conditions.The are2 mutants accumulate excessive amounts of(p)pp Gpp,which correlate with lower levels of photosynthetic proteins and higher amino acid levels.Collectively,these observations suggest that the alarmone(p)pp Gpp mediates nitrogen stress responses and may constitute a highly conserved mechanism from bacteria to plants.
文摘In this study, we analyze factors affecting the explosion limits of flammable refrigerants. We conclude that any method used for measuring flammable refrigerant explosion limits has its conditional restrictions. Flammable refrigerants in the atmosphere can also explode under certain conditions, when the concentration is approaching the explosion limits. An experimental study on the explosion limits of six kinds of flammable refrigerants is carried out with a mixture of refrigerant and combustible refrigerant, which has a similar effect to a flame retardant. An experimental apparatus was designed to test the explosion limits of mixtures made from three different nonflammable refrigerants and six different flammable refrigerants. Two practical models were developed to estimate the critical concentration for inhibiting explosion of refrigerant mixtures: one was made up of two flammable components with one nonflammable component, and the second was made up of one flammable component with two nonflammable components.
文摘Plants assimilate inorganic nitrogen absorbed from soil into organic forms as Gin and Glu through the glutamine synthetase/glutamine：2-oxoglutarate amidotransferase （GS/GOGAT） cycle. Whereas GS cata- lyzes the formation of Gin from Glu and ammonia, GOGAT catalyzes the transfer of an amide group from Gin to 2-oxoglutarate to produce two molecules of Glu. However, the regulatory role of the GS/GOGAT cycle in the carbon-nitrogen balance is not well understood. Here, we report the functional characterization of rice ABNORMAL CYTOKININ RESPONSE 1 （ABC1） gene that encodes a ferredoxin-dependent （Fd）- GOGAT. The weak mutant allele abcl-1 mutant shows a typical nitrogen-deficient syndrome, whereas the T-DNA insertional mutant abcl-2 is seedling lethal. Metabolomics analysis revealed the accumulation of an excessive amount of amino acids with high N/C ratio （Gin and Asn） and several intermediates in the tricarboxylic acid cycle in abcl-1, suggesting that ABC1 plays a critical role in nitrogen assimilation and carbon-nitrogen balance. Five non-synonymous single-nucleotide polymorphisms were identified in the ABC1 coding region and characterized as three distinct haplotypes, which have been highly and specifically differentiated between japonica and indica subspecies. Collectively, these results suggest that ABC1/ OsFd-GOGAT is essential for plant growth and development by modulating nitrogen assimilation and the carbon-nitrogen balance.
基金supported by the Priority Research Program of the Chinese Academy of Sciences(ZDRW-ZS-2019-2,QYZDBSSW-SMC021)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA08000000,XDB11020700)+1 种基金the National Program on Key Basic Research Projects(2013CB127000)the State Key Laboratory of Plant Genomics of China(2016A0219-11,SKLPG2013A0125-5)
文摘Land plants co-speciate with a diversity of continually expanding plant specialized metabolites(PSMs) and root microbial communities(microbiota).Homeostatic interactions between plants and root microbiota are essential for plant survival in natural environments.A growing appreciation of microbiota for plant health is fuelling rapid advances in genetic mechanisms of controlling microbiota by host plants.PSMs have long been proposed to mediate plant and single microbe interactions.However,the effects of PSMs,especially those evolutionarily new PSMs,on root microbiota at community level remain to be elucidated.Here,we discovered sesterterpenes in Arabidopsis thaliana,produced by recently duplicated prenyltransferase-terpene synthase(PT-TPS) gene clusters,with neo-functionalization.A single-residue substitution played a critical role in the acquisition of sesterterpene synthase(sesterTPS) activity in Brassicaceae plants.Moreover,we found that the absence of two root-specific sesterterpenoids,with similar chemical structure,significantly affected root microbiota assembly in similar patterns.Our results not only demonstrate the sensitivity of plant microbiota to PSMs but also establish a complete framework of host plants to control root microbiota composition through evolutionarily dynamic PSMs.
文摘Bird predation during seed maturation causes great loss to agricultural production.In this study,through GWAS analysis of a large-scale sorghum germplasm diversity panel,we identified that Tannin1,which encodes a WD40 protein functioning in the WD40/MYB/bHLH complex,controls bird feeding behavior in sorghum.Metabolic profiling analysis showed that a group of sorghum accessions preferred by birds contain mutated tan1-a/b alleles and accumulate significantly lower levels of anthocyanins and condensed tannin compounds.In contrast,a variety of aromatic and fatty acid-derived volatiles accumulate at significantly higher levels in these bird-preference accessions.We subsequently conducted both sparrow feeding and sparrow volatile attractant assays,which confirmed,respectively,the antifeedant and attractant functions of these differentially accumulated metabolites.In addition,the connection between the biosynthesis pathway of anthocyanin and proanthocyanidin and the pathway of fatty acid–derived volatile biosynthesis was demonstrated by discovering that Tannin1 complex modulates fatty acid biosynthesis by regulating the expression of SbGL2 in sorghum,thus affecting the accumulation of fatty acid-derived volatiles.Taken together,our study identified Tannin1 as the gene underlying the major locus controlling bird feeding behavior in sorghum,illustrating an example of the identification of an ecologically impactful molecular mechanism from field observation and providing significant insights into the chemistry of bird–plant ecological interactions.
基金the National Program on Key Basic Research Projects，the 'One hundred talents' project of the Chinese Academy of Sciences，the National Natural Sciences Foundation of China，the National Science Foundation，the State Key Laboratory of Plant Genomics of China
文摘Bitter acids, known for their use as beer flavoring and for their diverse biological activities, are predominantly formed in hop （Humulus lupulus） glandular trichomes. Branched short-chain acyI-CoAs （e.g. isobutyryI-CoA, isovaleryl- CoA and 2-methylbutyryI-CoA）, derived from the degradation of branched-chain amino acids （BCAAs）, are essential building blocks for the biosynthesis of bitter acids in hops. However, little is known regarding what components are needed to produce and maintain the pool of branched short-chain acyI-CoAs in hop trichomes. Here, we present several lines of evidence that both CoA ligases and thioesterases are likely involved in bitter acid biosynthesis. Recombinant HICCL2 （carboxyl CoA ligase） protein had high specific activity for isovaleric acid as a substrate （Kcat/Km = 4100 s-~ M-l）, whereas recombinant HICCL4 specifically utilized isobutyric acid （Kcat/Km = 1800 s-1 M-1） and 2-methylbutyric acid （Kcat/ Km = 6900 s-1 M-~） as substrates. Both HICCLs, like hop valerophenone synthase （HIVPS）, were expressed strongly in glandular trichomes and localized to the cytoplasm. Co-expression of HICCL2 and HICCL4 with HIVPS in yeast led to significant production of acylphloroglucinols （the direct precursors for bitter acid biosynthesis）, which further confirmed the biochemical function of these two HICCLs in vivo. Functional identification of a thioesterase that catalyzed the reverse reaction of CCLs in mitochondria, together with the comprehensive analysis of genes involved BCAA catabolism, supported the idea that cytosolic CoA ligases are required for linking BCAA degradation and bitter acid biosynthesis in glandular trichomes. The evolution and other possible physiological roles of branched short-chain fatty acid：CoA ligases in planta are also discussed.
文摘Nicotinamide adenine dinucleotide （NAD） biosynthesis, including synthesis from aspartate via the de novo pathway and from nicotinate （NA） via the Preiss-Handler pathway, is conserved in land plants. Diverse spe-cies of NA conjugates, which are mainly involved in NA detoxification, were also found in all tested land plants. Among these conjugates, MeNA （NA methyl ester） has been widely detected in angiosperm plants, although its physiological function and the underlying mechanism for its production in planta remain largely unknown. Here, we show that MeNA is an NAD precursor undergoing more efficient long-distance trans-port between organs than NA and nicotinamide in Arabidopsis. We found that Arabidopsis has one meth- yltransferase （designated AtNaMT1） capable of catalyzing carboxyl methylation of NA to yield MeNA and one methyl esterase （MES2） predominantly hydrolyzing MeNA back to NA. We further uncovered that the transfer of [^14C]MeNA from the root to leaf was significantly increased in both MES2 knockdown and NaMTl-overexpressing lines, suggesting that both NaMT1 and MES2 fine-tune the long-distance transport of MeNA, which is ultimately utilized for NAD production. Abiotic stress （salt, abscisic acid, and mannitol） treatments, which are known to exacerbate NAD degradation, induce the expression of NaMT1 but sup-press MES2 expression, suggesting that MeNA may play a role in stress adaption. Collectively, our study indicates that reversible methylation of NA controls the biosynthesis of MeNA in Arabidopsis, which pre-sumably functions as a detoxification form of free NA for efficient long-distance transport and eventually NAD production especially under abiotic stress, providing new insights into the relationship between NAD biosynthesis and NA conjugation in plants.
基金financially supported by the National Key R&D Program of China(2018YFA0900600)the National Natural Science Foundation of China(31970315)+1 种基金the Key R&D Program of Shandong Province(2019JZZY020610)the State Key Laboratory of Plant Genomics of China(grant no.SKLPG2016A-13)。
文摘Terpenes are the largest and most diverse class of plant specialized metabolites.Sesterterpenes(C25),which are derived from the plastid methylerythritol phosphate pathway,were recently characterized in plants.In Arabidopsis thaliana,four genes encoding geranylfarnesyl diphosphate synthase(GFPPS)(AtGFPPS1 to 4)are responsible for the production of GFPP,which is the common precursor for sesterterpene biosynthesis.However,the interplay between sesterterpenes and other known terpenes remain elusive.Here,we first provide genetic evidence to demonstrate that GFPPSs are responsible for sesterterpene production in Arabidopsis.Blockage of the sesterterpene pathway at the GFPPS step increased the production of geranylgeranyl diphosphate(GGPP)-derived terpenes.Interestingly,co-expression of sester TPSs in GFPPSOE(overexpression)plants rescued the phenotypic changes of GFPPS-OE plants by restoring the endogenous GGPP.We further demonstrated that,in addition to precursor(DMAPP/IPP)competition by GFPPS and GGPP synthase(GGPPS)in plastids,GFPPS directly decreased the activity of GGPPS through protein-protein interaction,ultimately leading to GGPP deficiency in planta.Our study provides a new regulatory mechanism of the plastidial terpenoid network in plant cells.
