Eleocharis Vivipara Research Articles

The genome of Eleocharis vivipara elucidates the genetics of C3-C4 photosynthetic plasticity and karyotype evolution in the Cyperaceae.

Eleocharis vivipara, an amphibious sedge in the Cyperaceae family, has several remarkable properties, most notably its alternate use of C3 photosynthesis underwater and C4 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 32.96 million years ago (Mya), and underwent a whole-genome 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 C4 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 C4 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 C4 photosynthesis in E. vivipara, and hypothesize that the evolution of C4 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 C3 and C4 photosynthesis, offering promising avenues for crop improvement and breeding.

Salt stress induces Kranz anatomy and expression of C4 photosynthetic enzymes in the amphibious sedge Eleocharis vivipara

Eleocharis vivipara Link is a unique amphibious leafless plant of the Cyperaceae. The terrestrial form develops culms with Kranz anatomy and C4-like traits, while the submerged form does culms with non-Kranz anatomy and C3 traits. The submerged form develops new culms with C4-like mode when exposed to air or exogenous abscisic acid. In this study, we investigated whether salt stress (0.05-0.3M NaCl) has a similar effect. When the submerged form was grown for one month in solutions of 0.1M NaCl and more, culm growth was strongly suppressed. However, these plants slowly developed new culms that had Kranz anatomy with chloroplast-abundant Kranz bundle sheath cells. Although the culms of the submerged form had only few stomata, culms grown in the NaCl solution had many stomata. The NaCl-grown culms also accumulated large amounts of C4 photosynthetic enzymes (phosphoenolpyruvate carboxylase and pyruvate Pi dikinase), and the cellular localization patterns of these enzymes and ribulose 1,5-bisphosphate carboxylase/oxygenase were similar to those in terrestrial culms. Accumulation of C4 enzymes increased in mature culms of the submerged form (with non-Kranz anatomy) when exposed to 0.2M NaCl solution for one week. These results suggest that salt stress induces development of Kranz anatomy and expression of C4 photosynthetic enzymes in the submerged C3 form of E. vivipara, whereas the anatomical and biochemical traits of C4 photosynthesis appear to be regulated independently.

Gibberellic acid induces non-Kranz anatomy with C4-like biochemical traits in the amphibious sedge Eleocharis vivipara.

Gibberellic acid induces photosynthetic tissues with non-Kranz anatomy and C4-like biochemical traits in terrestrial-form plants of Eleocharis vivipara. This suggests that the structural and biochemical traits are independently regulated. The amphibious leafless sedge, Eleocharis vivipara Link, develops culms (photosynthetic organs) with C4-like traits and Kranz anatomy under terrestrial conditions, and C3 traits and non-Kranz anatomy under submerged conditions. The conversion from C3 mode to C4-like mode in E. vivipara is reportedly mediated by abscisic acid. Here, we investigated the effects of gibberellic acid (GA) on the differentiation of anatomical and photosynthetic traits because GA is involved in heterophylly in aquatic plants. When 100µM GA was sprayed on terrestrial plants, the newly developed culms had non-Kranz anatomy in the basal part and Kranz-like anatomy in the upper part. In the basal part, the mesophyll cells were well developed, whereas the Kranz (bundle sheath) cells were reduced and contained few chloroplasts and mitochondria. Stomatal frequency was lower in the basal part than in the upper part. Nevertheless, these tissues had abundant accumulation and high activities of C4 photosynthetic enzymes and had C4-like δ13C values, as seen in the culms of the terrestrial form. When submerged plants were grown under water containing GA-biosynthesis inhibitors (uniconazole or paclobutrazol), the new culms had Kranz anatomy. The culms developed under paclobutrazol had the C3 pattern of cellular accumulation of photosynthetic enzymes. These data suggest that GA induces production of photosynthetic tissues with non-Kranz anatomy in terrestrial plants of E. vivipara, without concomitant expression of C3 biochemical traits. The data also suggest that the differentiation of C4 structural and biochemical traits is regulated independently.

水陸両生植物Eleocharis viviparaにおけるC3・C4光合成特性の発現調節 －陸生型に及ぼすオーキシンの影響－

水陸両生植物Eleocharis viviparaにおけるC3・C4光合成特性の発現調節 －陸生型に及ぼすオーキシンの影響－

Eleocharis viviparaにおけるC3・C4光合成特性の発現調節

Eleocharis viviparaにおけるC3・C4光合成特性の発現調節

Application of Gas Permeable Film for Cultivation of Aquatic Plants

Completely closed bags made with a gas permeable film are available for culture of two aquatic plants, Eleocharis vivipara and Sphagnum nemoreum. E. vivipara, the C3-C4 photosynthesis interconvertible plant, was successfully grown in a sugar free liquid medium and developed C3 type culms even under relatively high intensity of illumination. Growth of S. nemoreum was clearly stimulated in the bag using a sugar containing medium. The film system is promising for further study of responses to environmental factors such as intensity and wavelength of illumination.

Erratum to: Identification of C4 photosynthesis metabolism and regulatory-associated genes in Eleocharis vivipara by SSH

Erratum to: Identification of C4 photosynthesis metabolism and regulatory-associated genes in Eleocharis vivipara by SSH

Identification of C4 photosynthesis metabolism and regulatory-associated genes in Eleocharis vivipara by SSH

This is the first effort to investigate the candidate genes involved in kranz developmental regulation and C(4) metabolic fluxes in Eleocharis vivipara, which is a leafless freshwater amphibious plant and possesses a distinct culms anatomy structure and photosynthetic pattern in contrasting environments. A terrestrial specific SSH library was constructed to investigate the genes involved in kranz anatomy developmental regulation and C(4) metabolic fluxes. A total of 73 ESTs and 56 unigenes in 384 clones were identified by array hybridization and sequencing. In total, 50 unigenes had homologous genes in the databases of rice and Arabidopsis. The real-time quantitative PCR results showed that most of the genes were accumulated in terrestrial culms and ABA-induced culms. The C(4) marker genes were stably accumulated during the culms development process in terrestrial culms. With respect to C(3) culms, C(4) photosynthesis metabolism consumed much more transporters and translocators related to ion metabolism, organic acids and carbohydrate metabolism, phosphate metabolism, amino acids metabolism, and lipids metabolism. Additionally, ten regulatory genes including five transcription factors, four receptor-like proteins, and one BURP protein were identified. These regulatory genes, which co-accumulated with the culms developmental stages, may play important roles in culms structure developmental regulation, bundle sheath chloroplast maturation, and environmental response. These results shed new light on the C(4) metabolic fluxes, environmental response, and anatomy structure developmental regulation in E. vivipara.

Eleocharis vivipara におけるC3・C4光合成型の発現調節

Eleocharis vivipara におけるC3・C4光合成型の発現調節

Eleocharis vivipara はジベレリン生合成阻害剤処理によりKranz 型構造と C 3 型生化学特性をもつ葉を形成する

Eleocharis vivipara はジベレリン生合成阻害剤処理によりKranz 型構造と C 3 型生化学特性をもつ葉を形成する

Eleocharis viviparaにおけるC3・C4光合成形質の発現制御に及ぼすジベレリンの影響

Eleocharis viviparaにおけるC3・C4光合成形質の発現制御に及ぼすジベレリンの影響

C3-C4相互転換植物Eleocharis viviparaのPEPCの組換え体の調製と性状解析：最もKm値の低いC4型PEPCの発見

C3-C4相互転換植物Eleocharis viviparaのPEPCの組換え体の調製と性状解析：最もKm値の低いC4型PEPCの発見

Diversity and plasticity of C4 photosynthesis in Eleocharis (Cyperaceae).

Eleocharis contains many amphibious species, and displays diversity of photosynthetic mechanism (C3, C4 or C3-C4 intermediates). A unique feature of Eleocharis is the plasticity in the photosynthetic mechanism of some species in response to the environment. In this study, we have examined the culm anatomy and photosynthetic property of several Eleocharis species grown terrestrially and the changes in the newly produced culms over a short period time frame after switching from terrestrial to submerged condition. Eleocharis baldwinii (Torrey) Chapman is C4-like in terrestrial habitat, exhibiting O2 inhibition of photosynthesis with Rubisco expressed in both mesophyll and bundle sheath cells and PEPC strictly in the mesophyll cells, but switches to C3-C4 intermediacy when submerged. In addition to Eleocharis vivipara Link type 1 (which switches from C4-like to C3), two other photosynthetic types examined in this study were shown to have different responses to growth in either terrestrial or submerged conditions. E. vivipara type 2 is a typical C4 plant in the terrestrial habitat, but becomes a C3-C4 intermediate under submerged conditions. Further, terrestrially, E. vivipara type 3 is a C3-C4 intermediate, but when submerged the δ13C value increases to -6.7‰, indicating its use of bicarbonate as a major carbon source. The submerged form of this plant exhibited about three times higher photosynthetic O2 evolution rate, compared to the C3 species Eleocharis erythropoda Steudel. These Eleocharis species possess different molecular switches for regulating C4 gene expression in response to environmental stimuli both between different species, and in E. vivipara among different populations. The apparent expression of a bicarbonate transport system by E. vivipara type 3 while submerged represents a unique adaptation to low CO2 availability.

Environmental and hormonal regulation of gene expression of C 4 photosynthetic enzymes in the amphibious sedge Eleocharis vivipara

Eleocharis vivipara, an amphibious leafless sedge, develops C 4 traits with Kranz anatomy under terrestrial conditions and C 3 traits with non-Kranz anatomy under submerged conditions. To determine the molecular basis of these responses, we isolated a full-length cDNA for phospho enolpyruvate carboxylase (PEPC) from culms, the photosynthetic organs of the terrestrial form, and investigated the expression of this gene and two previously isolated isogenes for pyruvate,Pi dikinase (PPDK). The gene for PEPC, designated pep1, was 3303 bp long with a single open reading frame of 2904 nucleodides. Phylogenetic analysis indicated that the PEP1 protein is located between a cluster of C 4-form PEPCs of C 4 grasses and another large cluster including C 3- and CAM-form PEPCs of dicots and monocots and C 4-form PEPCs of the C 4 Flaveria. The pep1 and the two PPDK isogenes, which encode chloroplastic and cytosolic PPDK, respectively, were expressed more strongly in culms of the terrestrial form than in those of the submerged form. The transcript levels were strictly modulated, even within a single plant growing both underwater and above the water surface. Exogenous application of abscisic acid (ABA) to the submerged form induced the enhanced expression of these genes in mature culms with non-Kranz anatomy, as well as in newly developing culms with Kranz anatomy, indicating the expression of C 4 genes without coordinate tissue differentiation.

Effects of an inhibitor of phosphoenolpyruvate carboxylase on photosynthesis of the terrestrial forms of amphibious Eleocharis species.

The leafless amphibious sedge Eleocharis vivipara develops culms with C(4) traits and Kranz anatomy under terrestrial conditions, but develops culms with C(3) traits and non-Kranz anatomy under submerged conditions. The culms of the terrestrial form have high C(4) enzyme activities, while those of the submerged form have decreased C(4) enzyme activities. The culms accumulate ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) in the mesophyll cells (MC) and the bundle sheath cells. The Rubisco in the MC may be responsible for the operation of the C(3) pathway in the submerged form. To verify the presence of the C(3) cycle in the MC, we examined the effects of 3,3-dichloro-2-(dihydroxyphosphinoylmethyl) -propenoate (DCDP), an inhibitor of phosphoenolpyruvate carboxylase (PEPC), on photosynthesis in culms of the terrestrial forms of E. vivipara and related amphibious species, E. baldwinii and E. retroflexa ssp. chaetaria. When 1 mM DCDP was fed via the transpiration stream to excised leaves, photosynthesis was inhibited completely in Fimbristylis dichotoma (C(4) control), but by only 20% in potato (C(3) control). In the terrestrial Eleocharis plants, the degree of inhibition of photosynthesis by DCDP was intermediate between those of the C(4) and C(3) plants, at 58-81%. These results suggest that photosynthesis under DCDP treatment in the terrestrial Eleocharis plants is due mainly to fixation of atmospheric CO(2) by Rubisco and probably the C(3) cycle in the MC. These features are reminiscent of those in C(4)-like plants. Differential effects of DCDP on photosynthesis of the 3 Eleocharis species are discussed in relation to differences in the degree of Rubisco accumulation and C(3) activity in the MC.

Environmental Regulation of C3 and C4 Differentiation in the Amphibious Sedge Eleocharis vivipara

Environmental Regulation of C3 and C4 Differentiation in the Amphibious Sedge Eleocharis vivipara

C4 GENE EXPRESSION

C4 plants, including maize, Flaveria, amaranth, sorghum, and an amphibious sedge Eleocharis vivipara, have been employed to elucidate the molecular mechanisms and signaling pathways that control C4 photosynthesis gene expression. Current evidence suggests that pre-existing genes were recruited for the C4 pathway after acquiring potent and surprisingly diverse regulatory elements. This review emphasizes recent advances in our understanding of the creation of C4 genes, the activities of the C4 gene promoters consisting of synergistic and combinatorial enhancers and silencers, the use of 5' and 3' untranslated regions for transcriptional and posttranscriptional regulations, and the function of novel transcription factors. The research has also revealed new insights into unique or universal mechanisms underlying cell-type specificity, coordinate nuclear-chloroplast actions, hormonal, metabolic, stress and light responses, and the control of enzymatic activities by phosphorylation and reductive processes.

C4‐type gene expression is not directly dependent on Kranz anatomy in an amphibious sedge Eleocharis vivipara Link

Summary Eleocharis vivipara Link alters its photosynthetic mode depending on the growth environment. It utilizes C4 photosynthesis when grown under terrestrial conditions (terrestrial form) and C3 photosynthesis when grown under submerged conditions (submerged form). The photosynthetic organ (the mature internodal region of the culm) of the terrestrial form shows typical Kranz anatomy with well‐developed bundle sheath cells, while the bundle sheath cells of the submerged form are not developed. In the mature internodal region of the terrestrial form, expression of the genes encoding two carboxylases, the small subunit of ribulose 1,5‐bisphosphate carboxylase (RbcS) and phosphoenolpyruvate carboxylase (Ppc), occurred mainly in bundle sheath cells and in mesophyll cells, respectively, as seen in a typical C4 leaf. In the submerged form, RbcS was expressed in both bundle sheath cells and mesophyll cells, and no expression of Ppc was observed. In the immature internodal region with undeveloped bundle sheath cells, both life forms showed the same expression pattern as in C3 plants: RbcS expression was localized in mesophyll cells and no Ppc expression was observed. The C4‐type expression pattern was established concomitantly with the development of bundle sheath cells during tissue maturation in the terrestrial internode. In contrast to the terrestrial form, the submerged form maintains C3‐type gene expression during tissue maturation. When the terrestrial culm was submerged, a region of transition from the terrestrial form to the submerged form was established in newly sprouting culms. In this transitional region, C4‐type expression of the two carboxylase genes was still maintained even though the development of bundle sheath cells was repressed. This observation suggests that the C4‐type cell‐specific gene expression pattern does not depend on the formation of Kranz anatomy.

Induction of kranz anatomy and C4-like biochemical characteristics in a submerged amphibious plant by abscisic acid

The amphibious leafless sedge Eleocharis vivipara develops C4-like traits as well as Kranz anatomy under terrestrial conditions, but it develops C3-like traits without Kranz anatomy under submerged conditions. When submerged plants are exposed to aerial conditions, they rapidly produce new photosynthetic tissues with C4-like traits. In this study, experiments were performed to determine whether abscisic acid (ABA), a plant stress hormone, could induce the formation of photosynthetic tissues with Kranz anatomy and C4-like biochemical traits under water in the submerged form. When the submerged plants were grown in water containing 5 &mgr;M ABA, they developed new photosynthetic tissues with Kranz anatomy, forming well-developed Kranz (bundle sheath) cells that contained many organelles. The ABA-induced tissues accumulated large amounts of phosphoenolpyruvate carboxylase, pyruvate orthophosphate dikinase, and NAD-malic enzyme at the appropriate cellular sites. The tissues had 3.4 to 3.8 times more C4 enzyme activity than did tissues of the untreated submerged plants. Carbon-14 pulse and carbon-12 chase experiments revealed that the ABA-induced tissues fixed higher amounts of carbon-14 into C4 compounds and lower amounts of carbon-14 into C3 compounds as initial products than did the submerged plants and that they exhibited a C4-like pattern of carbon fixation under aqueous conditions of low carbon, indicating enhanced C4 capacity in the tissues. This report provides an example of the hormonal control of the differentiation of the structural and functional traits required for the C4 pathway.

Expression of C3 and C4 photosynthetic characteristics in the amphibious plant Eleocharis vivipara: structure and analysis of the expression of isogenes for pyruvate, orthophosphate dikinase.

Eleocharis vivipara, a unique leafless amphibious sedge, adopts the C4 mode of photosynthesis under terrestrial conditions and the C3 mode under submerged aquatic conditions. To analyze the molecular basis of these responses to the contrasting environments, we isolated and characterized two full-length cDNAs for a key C4 enzyme, pyruvate, orthophosphate dikinase (PPDK; EC 2.7.9.1). The isogenes for PPDK, designated ppdk1 and ppdk2, were highly homologous to one another but not identical. The PPDK1 protein, deduced from the nucleotide sequence of the cDNA, contained an extra domain at the amino terminus which, presumably, serves as a chloroplast transit peptide, while PPDK2 lacked this extra domain. It seems likely, therefore, that the ppdk1 and ppdk2 genes encode a chloroplastic and a cytosolic PPDK, respectively. Genomic Southern blot analysis revealed the existence of a small family of genes for PPDK in the genome of E. vivipara. Northern blot analysis indicate that both chloroplastic and cytosolic genes for PPDK are expressed simultaneously in the culms, a photosynthetic organ, of E. vivipara and that the pattern of expression of these genes differs between the growth forms.