Terpenoids are the main components contributing to the fragrance of Lilium‘Siberia’,and LiTPS2 plays a critical role in the biosynthesis of monoterpenoids.Although the major terpene synthases in Lilium‘Siberia’hav...Terpenoids are the main components contributing to the fragrance of Lilium‘Siberia’,and LiTPS2 plays a critical role in the biosynthesis of monoterpenoids.Although the major terpene synthases in Lilium‘Siberia’have been identified,how these TPS genes are transcriptionally regulated remains elusive in this distinguished flower.This study aimed to identify transcription factors that regulate the terpene synthesis in Lilium,and disclose the related underlying transcriptional regulation mechanism.In this study,we identified three R2R3-MYB TFs—LiMYB1,LiMYB305 and LiMYB330,which were involved in regulating the biosynthesis of terpenes in Lilium‘Siberia’.Quantitative real-time PCR showed spatial and temporal expression patterns consistent with the emission patterns of terpene compounds.When LiMYB1,LiMYB305 and LiMYB330were overexpressed in flowers,the release of some main monoterpenes,such as linalool and ocimene,as well as the expression of TPS genes,especially for LiTPS2,were enhanced.A virus-induced gene silencing(VIGS)assay showed that silencing these three LiMYBs decreased the level of monoterpenes by down-regulating the expression of the TPS genes.The yeast one-hybrid and transient expression assays indicated that all three LiMYBs could bind to and activate the promoter of LiTPS2.Moreover,the yeast two-hybrid assay verified that LiMYB1 could interact with LiMYB308 and LiMYB330,indicating their synergistic roles in the regulation of floral terpene biosynthesis.In general,these results indicated that LiMYB1,LiMYB305,and LiMYB330 might play essential roles in terpene biosynthesis in Lilium and would provide a new perspective for the transcriptional regulation of volatile terpenes in flowers.展开更多
Hemoglobin is responsible for transporting oxygen from the lungs to body tissues.Structurally,this protein is a tetramer composed of two a-globin chains and twoβ-globin chains.In sheep,the β-globin locus is of parti...Hemoglobin is responsible for transporting oxygen from the lungs to body tissues.Structurally,this protein is a tetramer composed of two a-globin chains and twoβ-globin chains.In sheep,the β-globin locus is of particular interest because it contains two different haplotypes,namely haplotype A(hap A)and hap B,which differ in length by more than 30 kb and do not undergo recombination with each other due to low sequence similarity(Bauer and Jung,1975;Jiang et al.,2015).The two haplotypes also differ in gene content with hap A possessing two clusters of hemoglobin gene families and hap B possessing only one(Aguiletam et al.,2004),which implies differentiation in their functional roles.Hap A was speculated to be associated with high-altitude adaptation in sheep(Hu et al.,2019).展开更多
The main part of oil-immersed power equipment is oil-paper insulation.At lower ambient temperatures,transformer oil will become viscous.As a result,compared to those at room temperature or operating temperature,the fr...The main part of oil-immersed power equipment is oil-paper insulation.At lower ambient temperatures,transformer oil will become viscous.As a result,compared to those at room temperature or operating temperature,the frequency domain dielectric properties of oil-paper insulation at low temperatures are drastically different.For evaluating the insulation condition of electrical equipment,it is essential to accurately determine their dielectric properties.This paper described the FDS test,the DC conductivity test,and the transformer oil viscosity test,which was carried out in a laboratory environment for different ageing of oil-immersed pressboard and transformer oil at 233–373 K.The ef-fects of temperature on the dielectric properties at the competing mechanisms of polarisation and conductivity loss were clarified based on variations of the FDS curves.Considering the viscosity change of ageing transformer oil at low temperatures,the Arrhenius and VFT viscosity equations were used to achieve a fitting calculation in the different temperature zones.Based on the molecular/ion transition model in the force field and electric field,the characterisation relationships between the dynamic viscosity,DC conductivity,and test temperature of transformer oil were established.The limita-tions of conventional transformer oil equivalent dielectric relaxation models over a wide temperature range were finally clarified by combining the test findings of the DC con-ductivity over a wide temperature range with observed and simulated calculations.This paper provides an essential theoretical reference when using the FDS test to diagnose the insulation performance of oil-immersed power equipment in extremely cold regions.展开更多
基金supported by Beijing Natural Science Foundation,China(Grant No.6202022)National Natural Science Foundation of China,China(Grant No.31971708)National Key Research and Development Program of China(Grant No.2019YFD1001002)。
文摘Terpenoids are the main components contributing to the fragrance of Lilium‘Siberia’,and LiTPS2 plays a critical role in the biosynthesis of monoterpenoids.Although the major terpene synthases in Lilium‘Siberia’have been identified,how these TPS genes are transcriptionally regulated remains elusive in this distinguished flower.This study aimed to identify transcription factors that regulate the terpene synthesis in Lilium,and disclose the related underlying transcriptional regulation mechanism.In this study,we identified three R2R3-MYB TFs—LiMYB1,LiMYB305 and LiMYB330,which were involved in regulating the biosynthesis of terpenes in Lilium‘Siberia’.Quantitative real-time PCR showed spatial and temporal expression patterns consistent with the emission patterns of terpene compounds.When LiMYB1,LiMYB305 and LiMYB330were overexpressed in flowers,the release of some main monoterpenes,such as linalool and ocimene,as well as the expression of TPS genes,especially for LiTPS2,were enhanced.A virus-induced gene silencing(VIGS)assay showed that silencing these three LiMYBs decreased the level of monoterpenes by down-regulating the expression of the TPS genes.The yeast one-hybrid and transient expression assays indicated that all three LiMYBs could bind to and activate the promoter of LiTPS2.Moreover,the yeast two-hybrid assay verified that LiMYB1 could interact with LiMYB308 and LiMYB330,indicating their synergistic roles in the regulation of floral terpene biosynthesis.In general,these results indicated that LiMYB1,LiMYB305,and LiMYB330 might play essential roles in terpene biosynthesis in Lilium and would provide a new perspective for the transcriptional regulation of volatile terpenes in flowers.
基金supported by the Sci-Tech Innovation 2030 Agenda(2022ZD0401403)Natural Science Basic Research Plan in Shaanxi Provine of China(2023-JC-YB-157)+1 种基金supported by the National Natural Science Foundation of China(U21A20120)Shaanxi Livestock and Poultry Breeding Double-chain Fusion Key Project(2022GD-TSLD-46-0401).
文摘Hemoglobin is responsible for transporting oxygen from the lungs to body tissues.Structurally,this protein is a tetramer composed of two a-globin chains and twoβ-globin chains.In sheep,the β-globin locus is of particular interest because it contains two different haplotypes,namely haplotype A(hap A)and hap B,which differ in length by more than 30 kb and do not undergo recombination with each other due to low sequence similarity(Bauer and Jung,1975;Jiang et al.,2015).The two haplotypes also differ in gene content with hap A possessing two clusters of hemoglobin gene families and hap B possessing only one(Aguiletam et al.,2004),which implies differentiation in their functional roles.Hap A was speculated to be associated with high-altitude adaptation in sheep(Hu et al.,2019).
基金Heilongjiang Provincial Postdoctoral Science Foundation,Grant/Award Number:LBH-Z22202The technology project of the State Grid Corporation of China Headquarters,Grant/Award Number:5500-202330167A-1-1-ZN。
文摘The main part of oil-immersed power equipment is oil-paper insulation.At lower ambient temperatures,transformer oil will become viscous.As a result,compared to those at room temperature or operating temperature,the frequency domain dielectric properties of oil-paper insulation at low temperatures are drastically different.For evaluating the insulation condition of electrical equipment,it is essential to accurately determine their dielectric properties.This paper described the FDS test,the DC conductivity test,and the transformer oil viscosity test,which was carried out in a laboratory environment for different ageing of oil-immersed pressboard and transformer oil at 233–373 K.The ef-fects of temperature on the dielectric properties at the competing mechanisms of polarisation and conductivity loss were clarified based on variations of the FDS curves.Considering the viscosity change of ageing transformer oil at low temperatures,the Arrhenius and VFT viscosity equations were used to achieve a fitting calculation in the different temperature zones.Based on the molecular/ion transition model in the force field and electric field,the characterisation relationships between the dynamic viscosity,DC conductivity,and test temperature of transformer oil were established.The limita-tions of conventional transformer oil equivalent dielectric relaxation models over a wide temperature range were finally clarified by combining the test findings of the DC con-ductivity over a wide temperature range with observed and simulated calculations.This paper provides an essential theoretical reference when using the FDS test to diagnose the insulation performance of oil-immersed power equipment in extremely cold regions.
