In angiosperms,floral architecture diversity reflects its significance in exploring plant evolution.Magnolia polytepala,an endemic and ancient species in China,possesses a unique multi-tepal trait.Notably,the origin a...In angiosperms,floral architecture diversity reflects its significance in exploring plant evolution.Magnolia polytepala,an endemic and ancient species in China,possesses a unique multi-tepal trait.Notably,the origin and formation of these multi-tepals are poorly understood.In this study,we investigated the origin and formation of multi-tepals from the inner floral whorl and elucidated the underlying molecular regulatory mechanisms by combining phenotypic analysis,sequencing,and molecular experiments.We found that the multi-tepals exhibited morpho-anatomical characteristics similar to normal tepals but differed from petaloid and normal stamens.The temporal dynamics of a large number of differentially expressed genes(DEGs)involved in multiple signaling(transduction)pathways contributed to multi-tepal primordia initiation during early floral differentiation.In particular,the dynamic expression of MpW OX4,MpCLE41,MpULT1,and MpKN1 might be responsible for floral meristem activation and maintenance,while MpTGA1 and MpEJ2 potentially regulated floral organ initiation.Floral homeotic genes,such as MapoAP3,contributed to subsequent organ identity specialization.We further isolated a nucleus-localized APETALA3 homolog from M.polytepala,terming it the MapoAPETALA3(MapoAP3)gene,which was expressed in almost all vegetative and reproductive tissues.Ectopically expressing MapoAP3 in Arabidopsis resulted in altered phenotypes of rosette leaves,inflorescences,and florets,particularly generating extra petals instead of undergoing homeotic organ conversion.This discovery revealed an additional function of MapoAP3 in regulating organ initiation in addition to its conserved B-function in floral architecture plasticity.In summary,the multi-tepals of M.polytepala originated from the early tepal primordia initiation event rather than stamen petalody.The formation of the multi-tepal trait was attributed to the coordinated regulation of several vital DEGs,with the MapoAP3 gene playing an important role.These results provide additional insight into the regulation underlying the floral architecture formation in ancient Magnolia species and suggest that manipulating the MapoAP3 gene may hold promising potential for genetic breeding in ornamental plants.展开更多
The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis,prevention and cure of the disease.The combined work of three researchers...The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis,prevention and cure of the disease.The combined work of three researchers,Alter H,Houghton M and Rice C,which set the basis for the diagnosis,treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents.This is a story of a transfusion-associated infection.A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis.That was followed by the identification of what was later known to be the hepatitis C virus(HCV)and the development of diagnostic tests.It all preceded the full molecular identification and demonstration of a causal effect.Finally it ended up with the development and discovery of a new class of therapeutic drugs,the direct acting antivirals,which are now used not only to cure the disease but most probably,to eliminate the problem.This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus.Finally,the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans.展开更多
The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied....The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.展开更多
After germination in the dark,plants produce a shoot apical hook and closed cotyledons to protect the quiescent shoot apical meristem(SAM),which is critical for seedling survival during skotomorphogenesis.The factors ...After germination in the dark,plants produce a shoot apical hook and closed cotyledons to protect the quiescent shoot apical meristem(SAM),which is critical for seedling survival during skotomorphogenesis.The factors that coordinate these processes,particularly SAM repression,remain enigmatic.Plant cuticles,multilayered structures of lipid components on the outermost surface of the aerial epidermis of all land plants,provide protection against desiccation and external environmental stresses.Whether and how cuticles regulate plant development are still unclear.Here,we demonstrate that mutants of BODYGUARD1(BDG1)and long-chain acyl-CoA synthetase2(LACS2),key genes involved in cutin biosynthesis,produce a short hypocotyl with an opened apical hook and cotyledons in which the SAM is activated during skotomorphogenesis.Light signaling represses expression of BDG1 and LACS2,as well as cutin biosynthesis.Transcriptome analysis revealed that cuticles are critical for skotomorphogenesis,particularly for the development and function of chloroplasts.Genetic and molecular analyses showed that decreased HOOKLESS1 expression results in apical hook opening in the mutants.When hypoxia-induced expression of LITTLE ZIPPER2 at the SAM promotes organ initiation in the mutants,the de-repressed expression of cell-cycle genes and the cytokinin response induce the growth of true leaves.Our results reveal previously unrecognized developmental functions of the plant cuticle during skotomorphogenesis and demonstrate a mechanism by which light initiates photomorphogenesis through dynamic regulation of cuticle synthesis to induce coordinated and systemic changes in organ development and growth during the skotomorphogenesis-to-photomorphogenesis transition.展开更多
基金supported by grants from the Postgraduate Research&Practice Innovation Program of Jiangsu Province(Grant No.KYCX19_1080)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Doctorate Fellowship Foundation of Nanjing Forestry University。
文摘In angiosperms,floral architecture diversity reflects its significance in exploring plant evolution.Magnolia polytepala,an endemic and ancient species in China,possesses a unique multi-tepal trait.Notably,the origin and formation of these multi-tepals are poorly understood.In this study,we investigated the origin and formation of multi-tepals from the inner floral whorl and elucidated the underlying molecular regulatory mechanisms by combining phenotypic analysis,sequencing,and molecular experiments.We found that the multi-tepals exhibited morpho-anatomical characteristics similar to normal tepals but differed from petaloid and normal stamens.The temporal dynamics of a large number of differentially expressed genes(DEGs)involved in multiple signaling(transduction)pathways contributed to multi-tepal primordia initiation during early floral differentiation.In particular,the dynamic expression of MpW OX4,MpCLE41,MpULT1,and MpKN1 might be responsible for floral meristem activation and maintenance,while MpTGA1 and MpEJ2 potentially regulated floral organ initiation.Floral homeotic genes,such as MapoAP3,contributed to subsequent organ identity specialization.We further isolated a nucleus-localized APETALA3 homolog from M.polytepala,terming it the MapoAPETALA3(MapoAP3)gene,which was expressed in almost all vegetative and reproductive tissues.Ectopically expressing MapoAP3 in Arabidopsis resulted in altered phenotypes of rosette leaves,inflorescences,and florets,particularly generating extra petals instead of undergoing homeotic organ conversion.This discovery revealed an additional function of MapoAP3 in regulating organ initiation in addition to its conserved B-function in floral architecture plasticity.In summary,the multi-tepals of M.polytepala originated from the early tepal primordia initiation event rather than stamen petalody.The formation of the multi-tepal trait was attributed to the coordinated regulation of several vital DEGs,with the MapoAP3 gene playing an important role.These results provide additional insight into the regulation underlying the floral architecture formation in ancient Magnolia species and suggest that manipulating the MapoAP3 gene may hold promising potential for genetic breeding in ornamental plants.
文摘The discovery of hepatitis C has been a landmark in public health as it brought the opportunity to save millions of lives through the diagnosis,prevention and cure of the disease.The combined work of three researchers,Alter H,Houghton M and Rice C,which set the basis for the diagnosis,treatment and prevention of hepatitis C apart from laying the ground work for a new approach to study infections in general and developing new antiviral agents.This is a story of a transfusion-associated infection.A series of clinical studies demonstrated the existence of an infectious agent associated with hepatitis.That was followed by the identification of what was later known to be the hepatitis C virus(HCV)and the development of diagnostic tests.It all preceded the full molecular identification and demonstration of a causal effect.Finally it ended up with the development and discovery of a new class of therapeutic drugs,the direct acting antivirals,which are now used not only to cure the disease but most probably,to eliminate the problem.This work started with Dr Alter H who demonstrated that a new virus was responsible for the majority of post-transfusion hepatitis followed by Houghton M who cloned the virus and developed the blood test to identify those cases that carried the virus.Finally,the work of Rice C demonstrated that a cloned HCV produced after applying molecular biology techniques could cause long-standing infection and cause the same disease as the one observed in humans.
基金Project supported by the National Natural Science Foundation of China
文摘The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.
基金supported by the National Natural Science Foundation of China(32270340 and 31970824 to X.L.and 32300304 to H.Z.)the project“Fulltime introduction of high-end talent research project”(2020HBQZYC004 and A202105008 to X.L.)from Hebei provincefunding from the Hebei Natural Science Foundation(C2021205013 to X.L.,C2021205043 to L.G.,and C2023205049 to Y.Sun).
文摘After germination in the dark,plants produce a shoot apical hook and closed cotyledons to protect the quiescent shoot apical meristem(SAM),which is critical for seedling survival during skotomorphogenesis.The factors that coordinate these processes,particularly SAM repression,remain enigmatic.Plant cuticles,multilayered structures of lipid components on the outermost surface of the aerial epidermis of all land plants,provide protection against desiccation and external environmental stresses.Whether and how cuticles regulate plant development are still unclear.Here,we demonstrate that mutants of BODYGUARD1(BDG1)and long-chain acyl-CoA synthetase2(LACS2),key genes involved in cutin biosynthesis,produce a short hypocotyl with an opened apical hook and cotyledons in which the SAM is activated during skotomorphogenesis.Light signaling represses expression of BDG1 and LACS2,as well as cutin biosynthesis.Transcriptome analysis revealed that cuticles are critical for skotomorphogenesis,particularly for the development and function of chloroplasts.Genetic and molecular analyses showed that decreased HOOKLESS1 expression results in apical hook opening in the mutants.When hypoxia-induced expression of LITTLE ZIPPER2 at the SAM promotes organ initiation in the mutants,the de-repressed expression of cell-cycle genes and the cytokinin response induce the growth of true leaves.Our results reveal previously unrecognized developmental functions of the plant cuticle during skotomorphogenesis and demonstrate a mechanism by which light initiates photomorphogenesis through dynamic regulation of cuticle synthesis to induce coordinated and systemic changes in organ development and growth during the skotomorphogenesis-to-photomorphogenesis transition.
