Style-stigma-like structures were regenerated from stamens of Crocus sativus L. The age of the stamen explant has an obvious effect on the induction rate. Auxin NAA. has larger effect on the induction of filament styl...Style-stigma-like structures were regenerated from stamens of Crocus sativus L. The age of the stamen explant has an obvious effect on the induction rate. Auxin NAA. has larger effect on the induction of filament style-stigma-like structure. Auxin NAA of higher concentration can lead to higher induction rate. Temperature and light have different effects on the induction of style-stigma-like structure from anther's filament of C. sativus with exogenous hormones at different levels. Ultraviolet tests show that style-stigma-like structure from anther's filament of C. sativus contains crocin, safranal and picrocrocin, contents of which are obviously more than those contained in the style-stigma-like from style. Floral reversion was observed in the induction of style-stigma-like structure from petals, ovaries and styles.展开更多
Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been ...Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been suggested as a reflection of ＂labor division＂ in pollination in which one type of stamens attracts pollinators and satisfies their demand for pollen as food and the other satisfies the plant＇s need for safe gamete dispersal. The extent and patterns of stamen differentiation differ notably among taxa with heterantherous flowers. Seven species with heteromorphic stamens in three genera were sampled from Leguminosae and Melastomataceae, and the morphological difference of androecia, pollen content, pollen histochemistry and viability, pollen micro- morphology, as well as the main pollinators were examined and compared. Pollen number differs significantly between stamen sets of the same flower in most species investigated, and a correlation of pollen number and anther size was substantiated. Higher pollen viabilities were found in the long （pollinating） stamens of Senna alata （L.） Roxb. and S. bicapsularis （L.） Roxb. Dimorphic pollen exine ornamentation is reported here for the first time in Fordiophytonfaberi Stapf. The height of stigma and anther tips of the long stamens in natural conditions was proved to be highly correlated, supporting the hypothesis that they contact similar areas of the pollinator＇s body.展开更多
Plant reproduction requires the coordinated development of both male and female reproductive organs.Jasmonic acid(JA)plays an essential role in stamen filament elongation.However,the mechanism by which the JA biosynth...Plant reproduction requires the coordinated development of both male and female reproductive organs.Jasmonic acid(JA)plays an essential role in stamen filament elongation.However,the mechanism by which the JA biosynthesis genes are regulated to promote stamen elongation remains unclear.Here,we show that the chromatin remodeling complex Imitation of Switch(ISWI)promotes stamen filament elongation by regulating JA biosynthesis.We show that AT-Rich Interacting Domain 5(ARID5)interacts with CHR11,CHR17,and RLT1,several known subunits of ISWI.Mutations in ARID5 and RLTs caused a reduced seed set due to greatly shortened stamen filaments.RNA-seq analyses reveal that the expression of key genes responsible for JA biosynthesis is significantly down-regulated in the arid5 and rlt mutants.Consistently,the JA levels are drastically decreased in both arid5 and rlt mutants.Chromatin immunoprecipitationquantitative PCR analyses further show that ARID5 is recruited to the chromatin of JA biosynthesis genes.Importantly,exogenous JA treatments can fully rescue the defects of stamen filament elongation in both arid5 and rlt mutants,leading to the partial recovery of fertility.Our results provide a clue how JA biosynthesisis positively regulated by the chromatin remodeling complex ISWI,thereby promoting stamen filament elongation in Arabidopsis.展开更多
As some of the earliest evolving flowering plants,waterlilies offer unique insights into angiosperm evolu-tion.Giant Amazonian waterlilies(genus Victoria)are of particular interest due to their production of the world...As some of the earliest evolving flowering plants,waterlilies offer unique insights into angiosperm evolu-tion.Giant Amazonian waterlilies(genus Victoria)are of particular interest due to their production of the world’s largest floating leaves and gigantic flowers that entrap pollinating beetles.Here,we report chromo-some-level genome assemblies of Victoria cruziana and three related waterlilies:Euryale ferox,Nymphaea mexicana,and Brasenia schreberi.We found an ancient whole-genome duplication event specific to the Nymphaeales.We reveal major gene duplication and loss events throughout the evolution of angiosperms,with substantial implications for flower development and the biosynthesis of floral volatile organic com-pounds(FVOCs)in waterlilies.Importantly,we report a unique division of labor in the stamen function of V.cruziana linked to beetle attraction by FVOCs.This is related to the ultra-high expression of VicSABATHa along with Vicchitinase,possibly linked to protection from damage by trapped beetles.Overexpression of VicSABATHa in tobacco leaves reveals a capacity to produce volatile fatty acids,confirming its role in their catalytic synthesis.Overall,these findings provide novel insights into the evolution and adaptations of waterlilies and flowering plants in general.展开更多
Proper stamen development is essential for plants to achieve their life cycles. Defects in stamen development will cause male sterility. A vast array of research efforts have been made to understand stamen development...Proper stamen development is essential for plants to achieve their life cycles. Defects in stamen development will cause male sterility. A vast array of research efforts have been made to understand stamen developmental processes and reg- ulatory mechanisms over the past decades. It is so far reported that phytohormones, including jasmonate, auxin, gibberellin, brassinosteroid, and cytokinin, play essential roles in regulation of stamen development. This review will briefly summarize the molecular basis for coordinated regulation of stamen development by jasmonate, auxin, and gibberellin in Arabidopsis.展开更多
Gibberellin （GA） and jasmonate （JA） are two types of phytohormones that play important roles during stamen development. For example, Arabidopsis plants deficient in either of GA or JA develop short stamens. An app...Gibberellin （GA） and jasmonate （JA） are two types of phytohormones that play important roles during stamen development. For example, Arabidopsis plants deficient in either of GA or JA develop short stamens. An apparent question to ask is whether GA action and JA action during stamen filament development are independent of each other or are in a hierarchy. Recent studies showed that GA modulates the expression of genes essential for JA biosynthesis to promote JA production and high levels of JA will induce the expression of three MYB genes MYB21, MYB24 and MYB57. These three MYB genes are crucial factors for the normal development of stamen filament in Arabidopsis.展开更多
Stamen is a unique plant organ wherein germ cells or microsporocytes that commit to meiosis are initiated from somatic cells during its early developmental process. While genes determining stamen identity are known ac...Stamen is a unique plant organ wherein germ cells or microsporocytes that commit to meiosis are initiated from somatic cells during its early developmental process. While genes determining stamen identity are known according to the ABC model of floral development, little information is available on how these genes affect germ cell initiation. By using the Affymetrix GeneChip Rice Genome Array to assess 51 279 tran- scripts, we established a dynamic gene expression profile （GEP） of the early developmental process of rice （Oryza sativa） stamen. Systematic analysis of the GEP data revealed novel expression patterns of some developmentally important genes including meiosis-, tapetum-, and phytohormone-related genes. Following the finding that a substantial amount of nuclear genes encoding photosynthetic proteins are ex- pressed at the low levels in early rice stamen, through the ChlP-seq analysis we found that a C-class MADS box protein, OsMADS58, binds many nuclear-encoded genes participated in photosystem and light reac- tions and the expression levels of most of them are increased when expression of OsMADS58 is downre- gulated in the osmads58 mutant. Furthermore, more pro-chloroplasts are observed and increased signals of reactive oxygen species are detected in the osmads58 mutant anthers. These findings implicate a novel link between stamen identity determination and hypoxia status establishment.展开更多
Male reproductive development is a complex biological process which includes the formation of the stamen with differentiated anther tissues, in which microspores/pollens are generated, then anther dehiscence and subse...Male reproductive development is a complex biological process which includes the formation of the stamen with differentiated anther tissues, in which microspores/pollens are generated, then anther dehiscence and subsequently pollination. Stamen specification and anther development involve a number of extraordinary events such as meristem transition, cell division and differentiation, cell to cell communication, etc., which need the cooperative interaction of sporophytic and gametophytic genes. The advent of various tools for rice functional gene identification, such as complete genome sequence, genome-wide microarrays, collections of mutants, has greatly facilitated our understanding of mechanisms of rice stamen specification and anther development. Male sterile lines are critical for hybrid rice breeding, therefore understanding these processes will not only contribute greatly to the basic knowledge of crop developmental biology, but also to the development of new varieties for hybrid rice breeding in the future.展开更多
Heteranthery,the occurrence of functionally and structurally distinct stamens within a flower,represents a striking example of convergent evolution among diverse animal-pollinated lineages.Although the ecological basi...Heteranthery,the occurrence of functionally and structurally distinct stamens within a flower,represents a striking example of convergent evolution among diverse animal-pollinated lineages.Although the ecological basis of this somatic polymorphism is understood,the developmental and molecular mechanisms are largely unknown.To address this knowledge gap,we selected Monochoria elata(Pontederiaceae)as our study system due to its typical heterantherous floral structure.We constructed a chromosome-level genome assembly of M.elata,conducted transcriptomic analyses and target phytohormone metabolome analysis to explore gene networks and hormones associated with heteranthery.We focused on three key stamen characteristics—colour,spatial patterning,and filament elongation—selected for their significant roles in stamen differentiation and their relevance to the functional diversity observed in heterantherous species.Our analyses suggest that gene networks involving MelLEAFY3,MADS-box,and TCP genes regulate stamen identity,with anthocyanin influencing colour,and lignin contributing to filament elongation.Additionally,variation in jasmonic acid and abscisic acid concentration between feeding and pollinating anthers appears to contribute to their morphological divergence.Our findings highlight gene networks and hormones associated with intra-floral stamen differentiation and indicate that whole genome duplications have likely facilitated the evolution of heteranthery during divergence from other Pontederiaceae without heteranthery.展开更多
文摘Style-stigma-like structures were regenerated from stamens of Crocus sativus L. The age of the stamen explant has an obvious effect on the induction rate. Auxin NAA. has larger effect on the induction of filament style-stigma-like structure. Auxin NAA of higher concentration can lead to higher induction rate. Temperature and light have different effects on the induction of style-stigma-like structure from anther's filament of C. sativus with exogenous hormones at different levels. Ultraviolet tests show that style-stigma-like structure from anther's filament of C. sativus contains crocin, safranal and picrocrocin, contents of which are obviously more than those contained in the style-stigma-like from style. Floral reversion was observed in the induction of style-stigma-like structure from petals, ovaries and styles.
基金supported by National Natural Science Foundation of China (30570314)the Knowledge Innovation Program of Chinese Academy of Sciences (Grant No.KSCX2-YW-Z-027)
文摘Flowers that have heteromorphic stamens （heterantherous flowers） have intrigued many researchers ever since the phenomenon was discovered in the 19th century. The morphological differentiation in androecia has been suggested as a reflection of ＂labor division＂ in pollination in which one type of stamens attracts pollinators and satisfies their demand for pollen as food and the other satisfies the plant＇s need for safe gamete dispersal. The extent and patterns of stamen differentiation differ notably among taxa with heterantherous flowers. Seven species with heteromorphic stamens in three genera were sampled from Leguminosae and Melastomataceae, and the morphological difference of androecia, pollen content, pollen histochemistry and viability, pollen micro- morphology, as well as the main pollinators were examined and compared. Pollen number differs significantly between stamen sets of the same flower in most species investigated, and a correlation of pollen number and anther size was substantiated. Higher pollen viabilities were found in the long （pollinating） stamens of Senna alata （L.） Roxb. and S. bicapsularis （L.） Roxb. Dimorphic pollen exine ornamentation is reported here for the first time in Fordiophytonfaberi Stapf. The height of stigma and anther tips of the long stamens in natural conditions was proved to be highly correlated, supporting the hypothesis that they contact similar areas of the pollinator＇s body.
基金supported by the National Natural Science Foundation of China(31830045,32025005)。
文摘Plant reproduction requires the coordinated development of both male and female reproductive organs.Jasmonic acid(JA)plays an essential role in stamen filament elongation.However,the mechanism by which the JA biosynthesis genes are regulated to promote stamen elongation remains unclear.Here,we show that the chromatin remodeling complex Imitation of Switch(ISWI)promotes stamen filament elongation by regulating JA biosynthesis.We show that AT-Rich Interacting Domain 5(ARID5)interacts with CHR11,CHR17,and RLT1,several known subunits of ISWI.Mutations in ARID5 and RLTs caused a reduced seed set due to greatly shortened stamen filaments.RNA-seq analyses reveal that the expression of key genes responsible for JA biosynthesis is significantly down-regulated in the arid5 and rlt mutants.Consistently,the JA levels are drastically decreased in both arid5 and rlt mutants.Chromatin immunoprecipitationquantitative PCR analyses further show that ARID5 is recruited to the chromatin of JA biosynthesis genes.Importantly,exogenous JA treatments can fully rescue the defects of stamen filament elongation in both arid5 and rlt mutants,leading to the partial recovery of fertility.Our results provide a clue how JA biosynthesisis positively regulated by the chromatin remodeling complex ISWI,thereby promoting stamen filament elongation in Arabidopsis.
基金supported by the National Natural Science Foundation of China(32272750 and 31970246)the Scientific and Technological Talents and Platform Program of Yunnan Province(Academician Expert Workstation,202305AF150165)the"Pioneer"and"Leading Goose"R&D Program of Zhejiang(2023C02028).
文摘As some of the earliest evolving flowering plants,waterlilies offer unique insights into angiosperm evolu-tion.Giant Amazonian waterlilies(genus Victoria)are of particular interest due to their production of the world’s largest floating leaves and gigantic flowers that entrap pollinating beetles.Here,we report chromo-some-level genome assemblies of Victoria cruziana and three related waterlilies:Euryale ferox,Nymphaea mexicana,and Brasenia schreberi.We found an ancient whole-genome duplication event specific to the Nymphaeales.We reveal major gene duplication and loss events throughout the evolution of angiosperms,with substantial implications for flower development and the biosynthesis of floral volatile organic com-pounds(FVOCs)in waterlilies.Importantly,we report a unique division of labor in the stamen function of V.cruziana linked to beetle attraction by FVOCs.This is related to the ultra-high expression of VicSABATHa along with Vicchitinase,possibly linked to protection from damage by trapped beetles.Overexpression of VicSABATHa in tobacco leaves reveals a capacity to produce volatile fatty acids,confirming its role in their catalytic synthesis.Overall,these findings provide novel insights into the evolution and adaptations of waterlilies and flowering plants in general.
基金The research is supported by the National Science Foundation of China，the Ministry of Scierce and Techno ogy
文摘Proper stamen development is essential for plants to achieve their life cycles. Defects in stamen development will cause male sterility. A vast array of research efforts have been made to understand stamen developmental processes and reg- ulatory mechanisms over the past decades. It is so far reported that phytohormones, including jasmonate, auxin, gibberellin, brassinosteroid, and cytokinin, play essential roles in regulation of stamen development. This review will briefly summarize the molecular basis for coordinated regulation of stamen development by jasmonate, auxin, and gibberellin in Arabidopsis.
文摘Gibberellin （GA） and jasmonate （JA） are two types of phytohormones that play important roles during stamen development. For example, Arabidopsis plants deficient in either of GA or JA develop short stamens. An apparent question to ask is whether GA action and JA action during stamen filament development are independent of each other or are in a hierarchy. Recent studies showed that GA modulates the expression of genes essential for JA biosynthesis to promote JA production and high levels of JA will induce the expression of three MYB genes MYB21, MYB24 and MYB57. These three MYB genes are crucial factors for the normal development of stamen filament in Arabidopsis.
文摘Stamen is a unique plant organ wherein germ cells or microsporocytes that commit to meiosis are initiated from somatic cells during its early developmental process. While genes determining stamen identity are known according to the ABC model of floral development, little information is available on how these genes affect germ cell initiation. By using the Affymetrix GeneChip Rice Genome Array to assess 51 279 tran- scripts, we established a dynamic gene expression profile （GEP） of the early developmental process of rice （Oryza sativa） stamen. Systematic analysis of the GEP data revealed novel expression patterns of some developmentally important genes including meiosis-, tapetum-, and phytohormone-related genes. Following the finding that a substantial amount of nuclear genes encoding photosynthetic proteins are ex- pressed at the low levels in early rice stamen, through the ChlP-seq analysis we found that a C-class MADS box protein, OsMADS58, binds many nuclear-encoded genes participated in photosystem and light reac- tions and the expression levels of most of them are increased when expression of OsMADS58 is downre- gulated in the osmads58 mutant. Furthermore, more pro-chloroplasts are observed and increased signals of reactive oxygen species are detected in the osmads58 mutant anthers. These findings implicate a novel link between stamen identity determination and hypoxia status establishment.
基金Supported by the National Key Basic Research Development Program of China (Grant Nos. 2007CB108700, 2009CB941500)National Natural Science Foundation of China (Grant No. 30725022)Shanghai Leading Academic Discipline Project (Grant No. B205)
文摘Male reproductive development is a complex biological process which includes the formation of the stamen with differentiated anther tissues, in which microspores/pollens are generated, then anther dehiscence and subsequently pollination. Stamen specification and anther development involve a number of extraordinary events such as meristem transition, cell division and differentiation, cell to cell communication, etc., which need the cooperative interaction of sporophytic and gametophytic genes. The advent of various tools for rice functional gene identification, such as complete genome sequence, genome-wide microarrays, collections of mutants, has greatly facilitated our understanding of mechanisms of rice stamen specification and anther development. Male sterile lines are critical for hybrid rice breeding, therefore understanding these processes will not only contribute greatly to the basic knowledge of crop developmental biology, but also to the development of new varieties for hybrid rice breeding in the future.
基金supported by grants from the National Natural Science Foundation of China(32100186)the Selfdetermined Project of the State Key Laboratory of Plant Diversity and Specialty Crops,Chinese Academy of Sciences,China(PDSC2023-5)+1 种基金the Special Research Assistant Project,Chinese Academy of Sciences(E2291M01)a Discovery Grant from the Natural Sciences and Engineering Research Council of Canada.
文摘Heteranthery,the occurrence of functionally and structurally distinct stamens within a flower,represents a striking example of convergent evolution among diverse animal-pollinated lineages.Although the ecological basis of this somatic polymorphism is understood,the developmental and molecular mechanisms are largely unknown.To address this knowledge gap,we selected Monochoria elata(Pontederiaceae)as our study system due to its typical heterantherous floral structure.We constructed a chromosome-level genome assembly of M.elata,conducted transcriptomic analyses and target phytohormone metabolome analysis to explore gene networks and hormones associated with heteranthery.We focused on three key stamen characteristics—colour,spatial patterning,and filament elongation—selected for their significant roles in stamen differentiation and their relevance to the functional diversity observed in heterantherous species.Our analyses suggest that gene networks involving MelLEAFY3,MADS-box,and TCP genes regulate stamen identity,with anthocyanin influencing colour,and lignin contributing to filament elongation.Additionally,variation in jasmonic acid and abscisic acid concentration between feeding and pollinating anthers appears to contribute to their morphological divergence.Our findings highlight gene networks and hormones associated with intra-floral stamen differentiation and indicate that whole genome duplications have likely facilitated the evolution of heteranthery during divergence from other Pontederiaceae without heteranthery.
