&lt;I&gt;Bienertia sinuspersici&lt;/I&gt; (Chenopodiaceae): A New Species from Southwest Asia and Discovery of a Third Terrestrial C&lt;SUB&gt;4&lt;/SUB&gt; Plant Without Kranz Anatomy

Akhani, Hossein; Barroca, João; Koteeva, N K; Voznesenskaya, Elena V.; Franceschi, Vincent R.; Edwards, Gerald E.; Ghaffari, Seyed Mahmood; Ziegler, H.

doi:10.1600/0363644054223684

Cited by 74 publications

(69 citation statements)

References 16 publications

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“…-The range of pollen variation between the two species (16 accessions examined) recognised for this genus is small; no significant discontinuity has been observed, confirming previous studies by Akhani et al (2003Akhani et al ( , 2005. One exception is a specimen of B. sinuspersici collected from the United Arab Emirates (Akhani 9186) which has a greater number of pores (51 ± 5).…”

Section: Interspecific and Interpopulation Variationssupporting

confidence: 82%

“…Suaedoideae includes Bienertia with two described species in the Irano-Turanian area and Suaeda with c. 80 -90 species, a cosmopolitan genus which is classified into two subgenera and eight sections (Schütze et al, 2003;Akhani et al, 2005;Kapralov et al, 2006). The subfamily is characterised by fleshy leaves, the presence of bracteoles, membranaceous in Suaeda or usually herbaceous in Bienertia, and seeds with a usually crustaceous testa.…”

Section: Number Suaedamentioning

confidence: 99%

“…The subfamily is characterised by fleshy leaves, the presence of bracteoles, membranaceous in Suaeda or usually herbaceous in Bienertia, and seeds with a usually crustaceous testa. Suaedoideae is a very interesting group, and unique among terrestrial plants in having a large diversity of photosynthetic types; notably in three species belonging to Suaeda and Bienertia, which undergo C 4 photosynthesis but do not have 'Kranz anatomy' (Haberlandt, 1914): both species of Bienertia (B. cycloptera and B. sinuspersici) and one species of Suaeda: S. aralocaspica (see Table I; and Freitag & Stichler, 2000Akhani et al, 2003Akhani et al, , 2005Edwards et al, 2004;Kapralov et al, 2006). The members of Suaedoideae are important characteristic components of arid and semi-arid inland saline communities and salt marsh habitats, with the exception of some species of Suaeda section Brezia which also occur in salt marshes of mesic climates.…”

Section: Number Suaedamentioning

confidence: 99%

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Pollen morphological studies in subfamily Suaedoideae (Chenopodiaceae)

Dehghani

Akhani

2009

Grana

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Section: Interspecific and Interpopulation Variationssupporting

confidence: 82%

Section: Number Suaedamentioning

confidence: 99%

Section: Number Suaedamentioning

confidence: 99%

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Pollen morphological studies in subfamily Suaedoideae (Chenopodiaceae)

Dehghani

Akhani

2009

Grana

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“…In both cases, the effective CO 2 concentration available for Rubisco is increased, thereby minimizing its oxygenase activity and, consequently, photorespiration in C 4 plants. This work and previous studies all indicate that the two SCC 4 Bienertia species function very similar to Kranz-type C 4 species, including the development of a C 4 -type PEPC, development of separate domains for spatial separation of functions and physiological responses typical of C 4 plants, and performance of C 4 in natural habitats based on carbon isotope values of biomass (Edwards et al, 2004;Akhani et al, 2005Akhani et al, , 2009Lara et al, 2006;Smith et al, 2009;Leisner et al, 2010).…”

Section: Discussionsupporting

confidence: 67%

Resolving the Compartmentation and Function of C4 Photosynthesis in the Single-Cell C4 Species Bienertia sinuspersici

2011

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Bienertia sinuspersici is a land plant known to perform C 4 photosynthesis through the location of dimorphic chloroplasts in separate cytoplasmic domains within a single photosynthetic cell. A protocol was developed with isolated protoplasts to obtain peripheral chloroplasts (P-CP), a central compartment (CC), and chloroplasts from the CC (C-CP) to study the subcellular localization of photosynthetic functions. Analyses of these preparations established intracellular compartmentation of processes to support a NAD-malic enzyme (ME)-type C 4 cycle. Western-blot analyses indicated that the CC has Rubisco from the C 3 cycle, the C 4 decarboxylase NAD-ME, a mitochondrial isoform of aspartate aminotransferase, and photorespiratory markers, while the C-CP and P-CP have high levels of Rubisco and pyruvate, Pidikinase, respectively. Other enzymes for supporting a NAD-ME cycle via an aspartate-alanine shuttle, carbonic anhydrase, phosophoenolpyruvate carboxylase, alanine, and an isoform of aspartate aminotransferase are localized in the cytosol. Functional characterization by photosynthetic oxygen evolution revealed that only the C-CP have a fully operational C 3 cycle, while both chloroplast types have the capacity to photoreduce 3-phosphoglycerate. The P-CP were enriched in a putative pyruvate transporter and showed light-dependent conversion of pyruvate to phosphoenolpyruvate. There is a larger investment in chloroplasts in the central domain than in the peripheral domain (6-fold more chloroplasts and 4-fold more chlorophyll). The implications of this uneven distribution for the energetics of the C 4 and C 3 cycles are discussed. The results indicate that peripheral and central compartment chloroplasts in the single-cell C 4 species B. sinuspersici function analogous to mesophyll and bundle sheath chloroplasts of Kranz-type C 4 species.Rubisco is the central CO 2 fixation enzyme in plants. It is a bifunctional enzyme, catalyzing the carboxylation as well as the oxygenation of ribulose-bisphosphate (RuBP) to 3-phosphoglycerate (3-PGA) and phosphoglycolate, respectively. While 3-PGA is subsequently utilized in the C 3 cycle to produce triose-phosphates, phosphoglycolate has no known metabolic use (Ogren, 1984) and needs to be detoxified by the plant. This process is known as photorespiration, which is not only energy consuming but also results in a net loss of previously fixed carbon and nitrogen. The rate of carboxylation versus oxygenation through Rubisco is directly related to the availability of CO 2 and the concentration of oxygen competing for the catalytic site of the enzyme. Since Rubisco is thought to have evolved under much higher levels of CO 2 than current atmospheric concentrations, it is believed that photorespiration was insignificant earlier in photosynthetic organisms. Under current atmospheric CO 2 levels, however, significant amounts (e.g. up to 25%) of previously fixed carbon may be lost through RuBP oxygenase activity under conditions that favor photorespiration, like high temperatures or water stres...

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“…Since plastid biogenesis and functions depend on the coordinated expression and import of thousands of nuclear-encoded proteins (Jarvis, 2008), the development and function of dimorphic chloroplasts in the single-cell C 4 system might involve distinct import pathways to regulate the selective import of proteins and mediate plastid differentiation. In this study, we identified two Toc159 homologs from the single-cell C 4 species B. sinuspersici (Akhani et al, 2005;Chuong et al, 2006). Analyses of the B. sinuspersici Toc159 sequences using various bioinformatics tools indicated that the C-terminal tails (CTs) possess general physicochemical and structural properties similar to the transit sequences of chloroplast preproteins.…”

Section: Introductionmentioning

confidence: 99%

A Transit Peptide–Like Sorting Signal at the C Terminus Directs the Bienertia sinuspersici Preprotein Receptor Toc159 to the Chloroplast Outer Membrane

Lung

Chuong

2012

Plant Cell

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Although Toc159 is known to be one of the key GTPase receptors for selective recognition of chloroplast preproteins, the mechanism for its targeting to the chloroplast surface remains unclear. To compare the targeting of these GTPase receptors, we identified two Toc159 isoforms and a Toc34 from Bienertia sinuspersici, a single-cell C 4 species with dimorphic chloroplasts in individual chlorenchyma cells. Fluorescent protein tagging and immunogold studies revealed that the localization patterns of Toc159 were distinctive from those of Toc34, suggesting different targeting pathways. Bioinformatics analyses indicated that the C-terminal tails (CTs) of Toc159 possess physicochemical and structural properties of chloroplast transit peptides (cTPs). These results were further confirmed by fluorescent protein tagging, which showed the targeting of CT fusion proteins to the chloroplast surface. The CT of Bs Toc159 in reverse orientation functioned as a cleavable cTP that guided the fluorescent protein to the stroma. Moreover, a Bs Toc34 mutant protein was retargeted to the chloroplast envelope using the CTs of Toc159 or reverse sequences of other cTPs, suggesting their conserved functions. Together, our data show that the C terminus and the central GTPase domain represent a novel dual domain-mediated sorting mechanism that might account for the partitioning of Toc159 between the cytosol and the chloroplast envelope for preprotein recognition.

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<I>Bienertia sinuspersici</I> (Chenopodiaceae): A New Species from Southwest Asia and Discovery of a Third Terrestrial C<SUB>4</SUB> Plant Without Kranz Anatomy

Cited by 74 publications

References 16 publications

Pollen morphological studies in subfamily Suaedoideae (Chenopodiaceae)

Pollen morphological studies in subfamily Suaedoideae (Chenopodiaceae)

Resolving the Compartmentation and Function of C4 Photosynthesis in the Single-Cell C4 Species Bienertia sinuspersici

A Transit Peptide–Like Sorting Signal at the C Terminus Directs the Bienertia sinuspersici Preprotein Receptor Toc159 to the Chloroplast Outer Membrane

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