Hunan is located at the evolutionary transitional zone edge of the Yunnan-Guizhou plateau,where tea germplasms are abundant.At present,although morphological,enzymological and molecular markers have been used to study...Hunan is located at the evolutionary transitional zone edge of the Yunnan-Guizhou plateau,where tea germplasms are abundant.At present,although morphological,enzymological and molecular markers have been used to study the genetic relationship of these tea germplasms.However,due to the complexity of the genetic background of tea germplasm resources,the evolution history and taxonomy of Hunan tea germplasm is still unclear.In this study,four Hunan tea landraces from the evolutionary transitional zone were collected,including nine'Chengbu Dongcha'(CBDC),eight'Jianghua Kucha'(JHKC),11'Rucheng Baimao'(RCBM)and eight'Anhua Yuntai'(AHYT).We used whole-genome re-sequencing to identify genetic variation,phylogenetic placement,and population structure among the four tea landraces and then scanned the genome for regions related to population potential selective.Across the samples,we identified an average of 1.38 million(M)SNPs and 6.82×10^(3)INDELs.Based on the high-quality SNPs,we performed neighbor-joining phylogenetic tree,population structure,and principal component analysis,all of which supported that the 36 tea germplasms could been divided into two groups,CBDC and AHYT were clustered into a group,and RCBM and JHKC were clustered into another group.With CBDC,JHKC,and RCBM as control,407,380,and 147 selected genes were identified in AHYT,respectively,were in the top 5%of F_(ST)and Log_(2)^(Ratioθπ)scores.The identified genes are mainly involved in stress tolerance,biosynthesis of important secondary metabolites,adaptability,and yield.These results will be helpful in the classification of tea germplasms and investigating selection–related genes.展开更多
Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding numerous applications,such as imaging,information encryption,and all-optical cohere...Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding numerous applications,such as imaging,information encryption,and all-optical coherent control of terahertz nonlinear phenomena.Topological insulators featuring unique spinmomentum-locked surface state have already exhibited very promising prospects in terahertz emission,detection,and modulation,which may lay a foundation for future on-chip topological insulator-based terahertz systems.However,polarization-shaped terahertz emitters based on topological insulators with an arbitrarily manipulated temporal evolution of the amplitude and the electric-field vector direction have not yet been explored.We systematically investigated the terahertz radiation from topological insulator Bi2Te3 nanofilms driven by femtosecond laser pulses and successfully realized the generation of efficient chiral terahertz waves with controllable chirality,ellipticity,and principal axis.The convenient engineering of the chiral terahertz waves was interpreted by a photogalvanic effect(PGE)-induced photocurrent,while the linearly polarized terahertz waves originated from linear PGE-induced shift currents.Our work not only provides further understanding of femtosecond coherent control of ultrafast spin currents but also describes an effective way to generate spin-polarized terahertz waves at the source.展开更多
文摘Hunan is located at the evolutionary transitional zone edge of the Yunnan-Guizhou plateau,where tea germplasms are abundant.At present,although morphological,enzymological and molecular markers have been used to study the genetic relationship of these tea germplasms.However,due to the complexity of the genetic background of tea germplasm resources,the evolution history and taxonomy of Hunan tea germplasm is still unclear.In this study,four Hunan tea landraces from the evolutionary transitional zone were collected,including nine'Chengbu Dongcha'(CBDC),eight'Jianghua Kucha'(JHKC),11'Rucheng Baimao'(RCBM)and eight'Anhua Yuntai'(AHYT).We used whole-genome re-sequencing to identify genetic variation,phylogenetic placement,and population structure among the four tea landraces and then scanned the genome for regions related to population potential selective.Across the samples,we identified an average of 1.38 million(M)SNPs and 6.82×10^(3)INDELs.Based on the high-quality SNPs,we performed neighbor-joining phylogenetic tree,population structure,and principal component analysis,all of which supported that the 36 tea germplasms could been divided into two groups,CBDC and AHYT were clustered into a group,and RCBM and JHKC were clustered into another group.With CBDC,JHKC,and RCBM as control,407,380,and 147 selected genes were identified in AHYT,respectively,were in the top 5%of F_(ST)and Log_(2)^(Ratioθπ)scores.The identified genes are mainly involved in stress tolerance,biosynthesis of important secondary metabolites,adaptability,and yield.These results will be helpful in the classification of tea germplasms and investigating selection–related genes.
基金This work was supported by Beijing Natural Science Foundation(Grant No.4194083)the National Natural Science Foundation of China(Grant Nos.61905007,61774013,11827807,and 61731001)+3 种基金the National Key R&D Program of China(Grant Nos.2019YFB2203102 and 2018YFB0407602)the International Collaboration Project(Grant No.B16001)the National Key Technology Program of China(Grant No.2017ZX01032101)the Open Project Program of Wuhan National Laboratory for Optoelectronics(Grant No.2018WNLOKF001).
文摘Arbitrary manipulation of broadband terahertz waves with flexible polarization shaping at the source has great potential in expanding numerous applications,such as imaging,information encryption,and all-optical coherent control of terahertz nonlinear phenomena.Topological insulators featuring unique spinmomentum-locked surface state have already exhibited very promising prospects in terahertz emission,detection,and modulation,which may lay a foundation for future on-chip topological insulator-based terahertz systems.However,polarization-shaped terahertz emitters based on topological insulators with an arbitrarily manipulated temporal evolution of the amplitude and the electric-field vector direction have not yet been explored.We systematically investigated the terahertz radiation from topological insulator Bi2Te3 nanofilms driven by femtosecond laser pulses and successfully realized the generation of efficient chiral terahertz waves with controllable chirality,ellipticity,and principal axis.The convenient engineering of the chiral terahertz waves was interpreted by a photogalvanic effect(PGE)-induced photocurrent,while the linearly polarized terahertz waves originated from linear PGE-induced shift currents.Our work not only provides further understanding of femtosecond coherent control of ultrafast spin currents but also describes an effective way to generate spin-polarized terahertz waves at the source.
