Floral meristem termination is a key step leading to carpel initiation and fruit development.The frequent occurrence of heat stress due to global warming often disruptsfloral determinacy,resulting in defective fruit f...Floral meristem termination is a key step leading to carpel initiation and fruit development.The frequent occurrence of heat stress due to global warming often disruptsfloral determinacy,resulting in defective fruit formation.However,the detailed mechanism behind this phenomenon is largely unknown.Here,we identify CRABS CLAW a(SlCRCa)as a key regulator offloral meristem termination in tomato.SlCRCa func-tions as an indispensablefloral meristem terminator by suppressing SlWUS activity through the TOMATO AGAMOUS 1(TAG1)–KNUCKLES(SlKNU)–INHIBITOR OF MERISTEM ACTIVITY(SlIMA)network.A direct binding assay revealed that SlCRCa specifically binds to the promoter and second intron of WUSCHEL(SlWUS).We also demonstrate that SlCRCa expression depends on brassinosteroid homeostasis in theflo-ral meristem,which is repressed by heat stress via the circadian factor EARLY FLOWERING 3(SlELF3).These results provide new insights intofloral meristem termination and the heat stress response inflowers and fruits of tomato and suggest that SlCRCa provides a platform for multiple protein interactions that may epigenetically abrogate stem cell activity at the transition fromfloral meristem to carpel initiation.展开更多
To further study the floral organogenesis and discussing the floral origin of Phytolacca, the procedures of floral organogenesis were observed in Phytolacca esculenta and Phytolacca zhejiangensis. The results showed t...To further study the floral organogenesis and discussing the floral origin of Phytolacca, the procedures of floral organogenesis were observed in Phytolacca esculenta and Phytolacca zhejiangensis. The results showed that the floral organogenesis was consistent in Phytolacca. Their sepals were 2/5 helix, and with counter-clockwise and clockwise, usually the first sepal located at non-median of abaxial side. The first sepal of Phytolacca esculenta was initiated at non-median of adaxial side. There was no evident relationship between sepal and stamen initiating position, and the stamens initiated on ring meristem, they initiated approximately at the same time, and when the androecium member was numerous, they initiated centrifugally, the outer stamen initiated irregularly. Carpel initiated alternately with inner stamens. And the carpels connected by septum, if the septum grew more, the carpel was syncarpous at morphology, otherwise the carpel was apocarpous at morphology. So the syncarpous and the apocarpous have no successively relationship on evolution. Ovule initiated inside the carpel and opposite to carpel. Androecium, carpel and ovule initiated at ring meristem.展开更多
The homologous genes FLORICAULA (FLO) in Antirrhinum and LEAFY (LFY) in Arabidopsis are known to regu- late the initiation of flowering in these two distantly related plant species. These genes are necessary also for ...The homologous genes FLORICAULA (FLO) in Antirrhinum and LEAFY (LFY) in Arabidopsis are known to regu- late the initiation of flowering in these two distantly related plant species. These genes are necessary also for the expression of downstream genes that control floral organ identity. We used Arabidopsis LFY cDNA as a probe to clone and sequence a papaya ortholog of LFY, PFL. It encodes a protein that shares 61% identity with the Arabidopsis LFY gene and 71% identity with the LFY homologs of the two woody tree species: California sycamore (Platanus racemosa) and black cottonwood (Populus trichocarpa). Despite the high sequence similarity within two conserved regions, the N-terminal proline-rich motif in papaya PFL differs from other members in the family. This difference may not affect the gene function of papaya PFL, since an equally divergent but a functional LFY ortholog NEEDLY of Pinus radiata has been reported. Genomic and BAC Southern analyses indicated that there is only one copy of PFL in the papaya genome. In situ hybridization experiments demonstrated that PFL is expressed at a relatively low level in leaf primordia, but it is expressed at a high level in the floral meristem. Quantitative PCR analyses revealed that PFL was expressed in flower buds of all three sex types - male, female, and hermaphrodite with marginal difference between hermaphrodite and unisexual flowers. These data suggest that PFL may play a similar role as LFY in flower development and has limited effect on sex differentiation in papaya.展开更多
花椰菜(Brassica oleracea var. botrytis)花球外植体成苗的形态发生途径是由原来发育成花器官的顶端分生组织改变发育途径,不经过脱分化阶段,直接成苗。这是花球外植体的顶端分生组织细胞由生殖生长状态向营养生长状态的逆转。在这一...花椰菜(Brassica oleracea var. botrytis)花球外植体成苗的形态发生途径是由原来发育成花器官的顶端分生组织改变发育途径,不经过脱分化阶段,直接成苗。这是花球外植体的顶端分生组织细胞由生殖生长状态向营养生长状态的逆转。在这一过程中,激素起着决定性作用。花蕾外植体乃是经脱分化后成苗的。展开更多
During reproductive development, rice plants develop unique flower organs which determine the final grain yield. OsMADS1, one of SEPALLATA-like MADS-box genes, has been unraveled to play critical roles in rice floral ...During reproductive development, rice plants develop unique flower organs which determine the final grain yield. OsMADS1, one of SEPALLATA-like MADS-box genes, has been unraveled to play critical roles in rice floral organ identity specification and floral meristem determinacy. However, the molecular mechanisms underlying interactions of OsMADS1 with other floral homeotic genes in regulating flower development remains largely elusive. In this work, we studied the genetic interactions of OsMADS1 with B-, C-, and D-class genes along with physical interactions among their proteins. We show that the physical and genetic interactions between OsMADS1 and OsMADS3 are essential for floral meristem activity maintenance and organ identity specification; while OsMADS1 physically and genetically interacts with OsMADS58 in regu- lating floral meristem determinacy and suppressing spikelet meristem reversion. We provided important genetic evidence to support the neofunctionalization of two rice C-class genes （OsMADS3 and OsMADS58） during flower development. Gene expression profiling and quantitative RT-PCR analyses further revealed that OsMADS1 affects the expression of many genes involved in floral identity and hormone signaling, and chromatin immunoprecipitation （ChlP）-PCR assay further demonstrated that OsMADS17 is a direct target gene of OsMADS1. Taken together, these results reveal that OsMADS1 has diversified regulatory functions in specifying rice floral organ and meristem identity, probably through its genetic and physical interactions with different floral homeotic regulators.展开更多
Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visib...Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visible leaflets, we characterized four independent mutants with reduced leaf complexity, proliferating floral meristem （pfm）, proliferating floral organ-2 （pfo-2）, fused leaflets1 （ful1） and umbrella leaflets （uml）, which were further identified as loss-of-function mutants of Arabidopsis orthologs LEAFY （LFY ）, UNUSUAL FLORAL ORGANS （UFO）, CUP-SHAPED COTYLEDON 2 （CUC2） and PIN-FORMED 1 （PIN1）, respectively. Comparing the leaf development of wild-type and mutants by a scanning electron microscopy approach, leaflet initiation and/or dissection were found to be affected in these mutants. Expression and phenotype analysis indicated that PFM/LjLFY and PFO/LjUFO determined the basipetal leaflet initiation manner in L. japonicus. Genetic analysis of ful1 and uml mutants and their double mutants revealed that the CUC2-like gene and auxin pathway also participated in leaflet dissection in L. japonicus, and their functions might influence cytokinin biogenesis directly or indirectly. Our results here suggest that multiple genes were interplayed and played conserved functions in controlling leaf complexity during compound leaf development in L. japonicus.展开更多
基金supported by the National Key Research and Development Program of China (2018YFD1000800).
文摘Floral meristem termination is a key step leading to carpel initiation and fruit development.The frequent occurrence of heat stress due to global warming often disruptsfloral determinacy,resulting in defective fruit formation.However,the detailed mechanism behind this phenomenon is largely unknown.Here,we identify CRABS CLAW a(SlCRCa)as a key regulator offloral meristem termination in tomato.SlCRCa func-tions as an indispensablefloral meristem terminator by suppressing SlWUS activity through the TOMATO AGAMOUS 1(TAG1)–KNUCKLES(SlKNU)–INHIBITOR OF MERISTEM ACTIVITY(SlIMA)network.A direct binding assay revealed that SlCRCa specifically binds to the promoter and second intron of WUSCHEL(SlWUS).We also demonstrate that SlCRCa expression depends on brassinosteroid homeostasis in theflo-ral meristem,which is repressed by heat stress via the circadian factor EARLY FLOWERING 3(SlELF3).These results provide new insights intofloral meristem termination and the heat stress response inflowers and fruits of tomato and suggest that SlCRCa provides a platform for multiple protein interactions that may epigenetically abrogate stem cell activity at the transition fromfloral meristem to carpel initiation.
文摘To further study the floral organogenesis and discussing the floral origin of Phytolacca, the procedures of floral organogenesis were observed in Phytolacca esculenta and Phytolacca zhejiangensis. The results showed that the floral organogenesis was consistent in Phytolacca. Their sepals were 2/5 helix, and with counter-clockwise and clockwise, usually the first sepal located at non-median of abaxial side. The first sepal of Phytolacca esculenta was initiated at non-median of adaxial side. There was no evident relationship between sepal and stamen initiating position, and the stamens initiated on ring meristem, they initiated approximately at the same time, and when the androecium member was numerous, they initiated centrifugally, the outer stamen initiated irregularly. Carpel initiated alternately with inner stamens. And the carpels connected by septum, if the septum grew more, the carpel was syncarpous at morphology, otherwise the carpel was apocarpous at morphology. So the syncarpous and the apocarpous have no successively relationship on evolution. Ovule initiated inside the carpel and opposite to carpel. Androecium, carpel and ovule initiated at ring meristem.
文摘The homologous genes FLORICAULA (FLO) in Antirrhinum and LEAFY (LFY) in Arabidopsis are known to regu- late the initiation of flowering in these two distantly related plant species. These genes are necessary also for the expression of downstream genes that control floral organ identity. We used Arabidopsis LFY cDNA as a probe to clone and sequence a papaya ortholog of LFY, PFL. It encodes a protein that shares 61% identity with the Arabidopsis LFY gene and 71% identity with the LFY homologs of the two woody tree species: California sycamore (Platanus racemosa) and black cottonwood (Populus trichocarpa). Despite the high sequence similarity within two conserved regions, the N-terminal proline-rich motif in papaya PFL differs from other members in the family. This difference may not affect the gene function of papaya PFL, since an equally divergent but a functional LFY ortholog NEEDLY of Pinus radiata has been reported. Genomic and BAC Southern analyses indicated that there is only one copy of PFL in the papaya genome. In situ hybridization experiments demonstrated that PFL is expressed at a relatively low level in leaf primordia, but it is expressed at a high level in the floral meristem. Quantitative PCR analyses revealed that PFL was expressed in flower buds of all three sex types - male, female, and hermaphrodite with marginal difference between hermaphrodite and unisexual flowers. These data suggest that PFL may play a similar role as LFY in flower development and has limited effect on sex differentiation in papaya.
文摘花椰菜(Brassica oleracea var. botrytis)花球外植体成苗的形态发生途径是由原来发育成花器官的顶端分生组织改变发育途径,不经过脱分化阶段,直接成苗。这是花球外植体的顶端分生组织细胞由生殖生长状态向营养生长状态的逆转。在这一过程中,激素起着决定性作用。花蕾外植体乃是经脱分化后成苗的。
文摘During reproductive development, rice plants develop unique flower organs which determine the final grain yield. OsMADS1, one of SEPALLATA-like MADS-box genes, has been unraveled to play critical roles in rice floral organ identity specification and floral meristem determinacy. However, the molecular mechanisms underlying interactions of OsMADS1 with other floral homeotic genes in regulating flower development remains largely elusive. In this work, we studied the genetic interactions of OsMADS1 with B-, C-, and D-class genes along with physical interactions among their proteins. We show that the physical and genetic interactions between OsMADS1 and OsMADS3 are essential for floral meristem activity maintenance and organ identity specification; while OsMADS1 physically and genetically interacts with OsMADS58 in regu- lating floral meristem determinacy and suppressing spikelet meristem reversion. We provided important genetic evidence to support the neofunctionalization of two rice C-class genes （OsMADS3 and OsMADS58） during flower development. Gene expression profiling and quantitative RT-PCR analyses further revealed that OsMADS1 affects the expression of many genes involved in floral identity and hormone signaling, and chromatin immunoprecipitation （ChlP）-PCR assay further demonstrated that OsMADS17 is a direct target gene of OsMADS1. Taken together, these results reveal that OsMADS1 has diversified regulatory functions in specifying rice floral organ and meristem identity, probably through its genetic and physical interactions with different floral homeotic regulators.
基金supported by the National Natural Science Foundation of China(30930009)the Ministry of Agriculture of China for Transgenic Research(2011ZX08009-003)the Foundation from the Institute of Plant Physiology and Ecology,SIBS
文摘Transcription factors and phytohormones have been reported to play crucial roles to regulate leaf complexity among plant species. Using the compound-leafed species Lotus japonicus, a model legume plant with five visible leaflets, we characterized four independent mutants with reduced leaf complexity, proliferating floral meristem （pfm）, proliferating floral organ-2 （pfo-2）, fused leaflets1 （ful1） and umbrella leaflets （uml）, which were further identified as loss-of-function mutants of Arabidopsis orthologs LEAFY （LFY ）, UNUSUAL FLORAL ORGANS （UFO）, CUP-SHAPED COTYLEDON 2 （CUC2） and PIN-FORMED 1 （PIN1）, respectively. Comparing the leaf development of wild-type and mutants by a scanning electron microscopy approach, leaflet initiation and/or dissection were found to be affected in these mutants. Expression and phenotype analysis indicated that PFM/LjLFY and PFO/LjUFO determined the basipetal leaflet initiation manner in L. japonicus. Genetic analysis of ful1 and uml mutants and their double mutants revealed that the CUC2-like gene and auxin pathway also participated in leaflet dissection in L. japonicus, and their functions might influence cytokinin biogenesis directly or indirectly. Our results here suggest that multiple genes were interplayed and played conserved functions in controlling leaf complexity during compound leaf development in L. japonicus.
