Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas ...Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and inconsistent.Our aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0–100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C_4) and from natural vegetation (C_3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0–10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C_4 above 30 cm soil depth increased by 4.5%–5% or 0.11–0.12 g·kg^(-1) on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation abandonment.The increase in the percentage of C_4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C_4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment.展开更多
C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. ...C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf–air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2 assimilation rate（A n） was enhanced as vapor pressure deficits increased. A close relationship between A n and stomatal conductance（g s） suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase（PEPC） and nicotinamide adenine dinucleotide phosphate-malate enzyme（NADP-ME）, whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme（NAD-ME） was higher.Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges.展开更多
Model organisms such as Arabidopsis(Arabidopsis thaliana)and rice(Oryza sativa)have proven essential for efficient scientific discovery and development of new methods.With the diversity of plant lineages,some importan...Model organisms such as Arabidopsis(Arabidopsis thaliana)and rice(Oryza sativa)have proven essential for efficient scientific discovery and development of new methods.With the diversity of plant lineages,some important processes such as C4 photosynthesis are not found in either Arabidopsis or rice,so new model species are needed.Due to their small diploid genomes,short life cycles,self-pollination,small adult statures and prolific seed production,domesticated foxtail millet(Setaria italica)and its wild ancestor,green foxtail(S.viridis),have recently been proposed as novel model species for functional genomics of the Panicoideae,especially for study of C4 photosynthesis.This review outlines the development of these species as model organisms,and discusses current challenges and future potential of a Setaria model.展开更多
Poaceae(the grasses)includes rice,maize,wheat,and other crops,and is the most economically important angiosperm family.Poaceae is also one of the largest plant families,consisting of over 11000 species with a global d...Poaceae(the grasses)includes rice,maize,wheat,and other crops,and is the most economically important angiosperm family.Poaceae is also one of the largest plant families,consisting of over 11000 species with a global distribution that contributes to diverse ecosystems.Poaceae species are classified into 12 subfamilies,with generally strong phylogenetic support for their monophyly.However,many relationships within subfamilies,among tribes and/or subtribes,remain uncertain.To better resolve the Poaceae phylogeny,we generated 342 transcriptomic and seven genomic datasets;these were combined with other genomic and transcriptomic datasets to provide sequences for 357 Poaceae species in 231 genera,representing 45 tribes and all 12 subfamilies.Over 1200 low-copy nuclear genes were retrieved from these datasets,with several subsets obtained using additional criteria,and used for coalescent analyses to reconstruct a Poaceae phylogeny.Our results strongly support the monophyly of 11 subfamilies;however,the subfamily Puelioideae was separated into two non-sister clades,one for each of the two previously defined tribes,supporting a hypothesis that places each tribe in a separate subfamily.Molecular clock analyses estimated the crown age of Poaceae to be101 million years old.Ancestral character reconstruction of C3/C4 photosynthesis supports the hypothesis of multiple independent origins of C4 photosynthesis.These origins are further supported by phylogenetic analysis of the ppc gene family that encodes the phosphoenolpyruvate carboxylase,which suggests that members of three paralogous subclades(ppc-aL1a,ppc-aL1b,and ppcB2)were recruited as functional C4 ppc genes.This study provides valuable resources and a robust phylogenetic framework for evolutionary analyses of the grass family.展开更多
Currently, single-cell C4 photosynthesis has been reported in four terrestrial plant species, Bienertia cycloptera, B. sinuspersici, B. kavirense and Suaeda aralocaspica, of family Chenopodiaceae. These species posses...Currently, single-cell C4 photosynthesis has been reported in four terrestrial plant species, Bienertia cycloptera, B. sinuspersici, B. kavirense and Suaeda aralocaspica, of family Chenopodiaceae. These species possess novel mechanisms of C4 photosynthesis through spatial partitioning of organelles and key enzymes in distinct cytoplasmic domains within single chlorenchyma cells. Anatomical and biochemical studies have shown that the three Bienertia species and S. aralocaspica utilize biochemical and organellar compartmentation to achieve the equivalent spatial separation of Kranz anatomy but within a single photosynthetic cell. These discoveries have challenged the paradigm for C4 photosynthesis in terrestrial plants which had suggested for more than 40 years that the Kranz feature was indispensably required for its C4 function. In this review, we focus on the recent progress in understanding the cellular and molecular mechanisms that control the spatial relationship of organelles in these unique single-cell C4 systems. The demonstrated interaction of dimorphic chloroplasts with microtubules and actin filaments has shed light on the importance of these cytoskeleton components in the intracellular partitioning of organelles. Future perspectives on the potential function of the cytoskeleton in targeting gene products to specific subcellular compartments are discussed.展开更多
Eleocharis vivipara,an amphibious sedge in the Cyperaceae family,has several remarkable properties,most notably its alternate use of C_(3)photosynthesis underwater and C_(4)photosynthesis on land.However,the absence o...Eleocharis vivipara,an amphibious sedge in the Cyperaceae family,has several remarkable properties,most notably its alternate use of C_(3)photosynthesis underwater and C_(4)photosynthesis on land.However,the absence of genomic data has hindered its utility for evolutionary and genetic research.Here,we present a high-quality genome for E.vivipara,representing the first chromosome-level genome for the Eleocharis genus,with an approximate size of 965.22 Mb mainly distributed across 10 chromosomes.Its Hi–C pattern,chromosome clustering results,and one-to-one genome synteny across two subgroups indicates a tetraploid structure with chromosome count 2n=4x=20.Phylogenetic analysis suggests that E.vivipara diverged from Cyperus esculentus approximately 32.96million years ago(Mya),and underwent a wholegenome duplication(WGD)about 3.5 Mya.Numerous fusion and fission events were identified between the chromosomes of E.vivipara and its close relatives.We demonstrate that E.vivipara has holocentromeres,a chromosomal feature which can maintain the stability of such chromosomal rearrangements.Experimental transplantation and cross-section studies showed its terrestrial culms developed C_(4)Kranz anatomy with increased number of chloroplasts in the bundle sheath(BS)cells.Gene expression and weighted gene co-expression network analysis(WGCNA)showed overall elevated expression of core genes associated with the C_(4)pathway,and significant enrichment of genes related to modified culm anatomy and photosynthesis efficiency.We found evidence of mixed nicotinamide adenine dinucleotide-malic enzyme and phosphoenolpyruvate carboxykinase type C_(4)photosynthesis in E.vivipara,and hypothesize that the evolution of C_(4)photosynthesis predates the WGD event.The mixed type is dominated by subgenome A and supplemented by subgenome B.Collectively,our findings not only shed light on the evolution of E.vivipara and karyotype within the Cyperaceae family,but also provide valuable insights into the transition between C_(3)and C_(4)photosynthesis,offering promising avenues for crop improvement and breeding.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.4157301241571130041 U1612441)
文摘Intensive soil tillage is a significant factor in soil organic matter decline in cultivated soils. Both cultivation abandonment and foregoing tillage have been encouraged in the past 30 years to reduce greenhouse gas emissions and soil erosion. However, the dynamic processes of soil organic carbon (SOC) in areas of either continuous cultivation or abandonment remain unclear and inconsistent.Our aims were to assess and model the dynamic processes of SOC under continuous tillage and after cultivation abandonment in the black soil of Northeast China. Soil profiles were collected of cultivated or abandoned land with cultivation history of 0–100 years. An isotope mass balance equation was used to calculate the proportion of SOC derived from corn debris (C_4) and from natural vegetation (C_3) to deduce the dynamic process. Approximately 40% of SOC in the natural surface soil (0–10 cm) was eroded in the first 5 years of cultivation, increasing to about 75% within 40 years, before a slow recovery. C_4 above 30 cm soil depth increased by 4.5%–5% or 0.11–0.12 g·kg^(-1) on average per year under continuous cultivation, while it decreased by approximately 0.34% annually in the surface soil after cultivation abandonment.The increase in the percentage of C_4 was fitted to a linear equation with given intercepts in the upper 30 cm of soil in cultivated land. A significant relationship between the change of C_4 and time was found only in the surface soil after abandonment of cultivation. These results demonstrate the loss and accumulation of corn-derived SOC in surface black soil of Northeast China under continuous tillage or cultivation abandonment.
基金supported by the National Natural Science Foundation of China (No.31070538 and No.31370599)the Fundamental Research Funds for the Central Universities (No.: QN2011026)
文摘C4 plants possess better drought tolerance than C3 plants. However, Hedysarum scoparium, a C3 species, is dominant and widely distributed in the desert areas of northwestern China due to its strong drought tolerance. This study compared it with Haloxylon ammodendron, a C4 species, regarding the interactive effects of drought stress and different leaf–air vapor pressure deficits. Variables of interest included gas exchange, the activity levels of key C4 photosynthetic enzymes, and cellular anatomy. In both species, gas exchange parameters were more sensitive to high vapor pressure deficit than to strong water stress, and the net CO2 assimilation rate（A n） was enhanced as vapor pressure deficits increased. A close relationship between A n and stomatal conductance（g s） suggested that the species shared a similar response mechanism. In H. ammodendron, the activity levels of key C4 enzymes were higher, including those of phosphoenolpyruvate carboxylase（PEPC） and nicotinamide adenine dinucleotide phosphate-malate enzyme（NADP-ME）, whereas in H. scoparium, the activity level of nicotinamide adenine dinucleotide-malate enzyme（NAD-ME） was higher.Meanwhile, H. scoparium utilized adaptive structural features, including a larger relative vessel area and a shorter distance from vein to stomata, which facilitated the movement of water. These findings implied that some C4 biochemical pathways were present in H. scoparium to respond to environmental challenges.
基金supported by Fundamental Research Funds of CAAS(2014ZL002)National High Technology Research and Development Program of China(2013AA102603)+1 种基金the National Natural Science Foundation of China(31171560,31301328)China Agricultural Research System(CARS07-12.5-A02).
文摘Model organisms such as Arabidopsis(Arabidopsis thaliana)and rice(Oryza sativa)have proven essential for efficient scientific discovery and development of new methods.With the diversity of plant lineages,some important processes such as C4 photosynthesis are not found in either Arabidopsis or rice,so new model species are needed.Due to their small diploid genomes,short life cycles,self-pollination,small adult statures and prolific seed production,domesticated foxtail millet(Setaria italica)and its wild ancestor,green foxtail(S.viridis),have recently been proposed as novel model species for functional genomics of the Panicoideae,especially for study of C4 photosynthesis.This review outlines the development of these species as model organisms,and discusses current challenges and future potential of a Setaria model.
基金supported by funds from Eberly College of Science and the Huck Institutes of the Life Sciences at the Pennsylvania State University and from grants from the National Natural Science Foundation of China(31770242 and 31970224)funds from the Ministry of Education Key Laboratory of Biodiversity Science and Ecological Engineering and State Key Laboratory of Genetic Engineering at Fudan University.
文摘Poaceae(the grasses)includes rice,maize,wheat,and other crops,and is the most economically important angiosperm family.Poaceae is also one of the largest plant families,consisting of over 11000 species with a global distribution that contributes to diverse ecosystems.Poaceae species are classified into 12 subfamilies,with generally strong phylogenetic support for their monophyly.However,many relationships within subfamilies,among tribes and/or subtribes,remain uncertain.To better resolve the Poaceae phylogeny,we generated 342 transcriptomic and seven genomic datasets;these were combined with other genomic and transcriptomic datasets to provide sequences for 357 Poaceae species in 231 genera,representing 45 tribes and all 12 subfamilies.Over 1200 low-copy nuclear genes were retrieved from these datasets,with several subsets obtained using additional criteria,and used for coalescent analyses to reconstruct a Poaceae phylogeny.Our results strongly support the monophyly of 11 subfamilies;however,the subfamily Puelioideae was separated into two non-sister clades,one for each of the two previously defined tribes,supporting a hypothesis that places each tribe in a separate subfamily.Molecular clock analyses estimated the crown age of Poaceae to be101 million years old.Ancestral character reconstruction of C3/C4 photosynthesis supports the hypothesis of multiple independent origins of C4 photosynthesis.These origins are further supported by phylogenetic analysis of the ppc gene family that encodes the phosphoenolpyruvate carboxylase,which suggests that members of three paralogous subclades(ppc-aL1a,ppc-aL1b,and ppcB2)were recruited as functional C4 ppc genes.This study provides valuable resources and a robust phylogenetic framework for evolutionary analyses of the grass family.
文摘Currently, single-cell C4 photosynthesis has been reported in four terrestrial plant species, Bienertia cycloptera, B. sinuspersici, B. kavirense and Suaeda aralocaspica, of family Chenopodiaceae. These species possess novel mechanisms of C4 photosynthesis through spatial partitioning of organelles and key enzymes in distinct cytoplasmic domains within single chlorenchyma cells. Anatomical and biochemical studies have shown that the three Bienertia species and S. aralocaspica utilize biochemical and organellar compartmentation to achieve the equivalent spatial separation of Kranz anatomy but within a single photosynthetic cell. These discoveries have challenged the paradigm for C4 photosynthesis in terrestrial plants which had suggested for more than 40 years that the Kranz feature was indispensably required for its C4 function. In this review, we focus on the recent progress in understanding the cellular and molecular mechanisms that control the spatial relationship of organelles in these unique single-cell C4 systems. The demonstrated interaction of dimorphic chloroplasts with microtubules and actin filaments has shed light on the importance of these cytoskeleton components in the intracellular partitioning of organelles. Future perspectives on the potential function of the cytoskeleton in targeting gene products to specific subcellular compartments are discussed.
基金funded by the National Natural Science Foundation of China(32300217)the National Key R&D Program of China(2023YFA0914600)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2022A1515110358)the Guangdong Science and Technology Foundation,“Zhu Jiang Talent Innovation”project(2019ZT08N628)the Special Funds for Science Technology Innovation and Industrial Development of Shenzhen Dapeng New District(PT202101-01)。
文摘Eleocharis vivipara,an amphibious sedge in the Cyperaceae family,has several remarkable properties,most notably its alternate use of C_(3)photosynthesis underwater and C_(4)photosynthesis on land.However,the absence of genomic data has hindered its utility for evolutionary and genetic research.Here,we present a high-quality genome for E.vivipara,representing the first chromosome-level genome for the Eleocharis genus,with an approximate size of 965.22 Mb mainly distributed across 10 chromosomes.Its Hi–C pattern,chromosome clustering results,and one-to-one genome synteny across two subgroups indicates a tetraploid structure with chromosome count 2n=4x=20.Phylogenetic analysis suggests that E.vivipara diverged from Cyperus esculentus approximately 32.96million years ago(Mya),and underwent a wholegenome duplication(WGD)about 3.5 Mya.Numerous fusion and fission events were identified between the chromosomes of E.vivipara and its close relatives.We demonstrate that E.vivipara has holocentromeres,a chromosomal feature which can maintain the stability of such chromosomal rearrangements.Experimental transplantation and cross-section studies showed its terrestrial culms developed C_(4)Kranz anatomy with increased number of chloroplasts in the bundle sheath(BS)cells.Gene expression and weighted gene co-expression network analysis(WGCNA)showed overall elevated expression of core genes associated with the C_(4)pathway,and significant enrichment of genes related to modified culm anatomy and photosynthesis efficiency.We found evidence of mixed nicotinamide adenine dinucleotide-malic enzyme and phosphoenolpyruvate carboxykinase type C_(4)photosynthesis in E.vivipara,and hypothesize that the evolution of C_(4)photosynthesis predates the WGD event.The mixed type is dominated by subgenome A and supplemented by subgenome B.Collectively,our findings not only shed light on the evolution of E.vivipara and karyotype within the Cyperaceae family,but also provide valuable insights into the transition between C_(3)and C_(4)photosynthesis,offering promising avenues for crop improvement and breeding.
