The taxonomic position of C3 and C4 &lt;i&gt;Alloteropsis semialata&lt;/i&gt; (Poaceae)  in southern Africa

Russell, G. E. Gibbs

doi:10.4102/abc.v14i2.1160

Cited by 20 publications

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“…A similar difference in leaf morphology exists between the C 3 and C 4 subspecies of A. semialata (Gibbs-Russell, 1983), highlighting potential links between photosynthetic pathway evolution and changes to leaf anatomy and morphology.…”

Section: Discussionmentioning

confidence: 75%

“…Gibbs-Russell (1983) designated the C 3 and C 4 variants of A. semialata as subspecies rather than separate species because herbarium specimens included apparent intermediates between the C 3 and C 4 forms and therefore suggested there was gene flow between them. However, recent molecular phylogenies have shown some grass genera to be polyphyletic (e.g.…”

Section: Introductionmentioning

confidence: 99%

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A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

et al. 2008

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Background and AimsThe grass Alloteropsis semialata is the only plant species with both C3 and C4 subspecies. It therefore offers excellent potential as a model system for investigating the genetics, physiology and ecological significance of the C4 photosynthetic pathway. Here, a molecular phylogeny of the genus Alloteropsis is constructed to: (a) confirm the close relationship between the C3 and C4 subspecies of A. semialata; and (b) infer evolutionary relationships between species within the Alloteropsis genus.MethodsThe chloroplast gene ndhF was sequenced from 12 individuals, representing both subspecies of A. semialata and all four of the other species in the genus. ndhF sequences were added to those previously sequenced from the Panicoideae, and used to construct a phylogenetic tree.Key ResultsThe phylogeny confirms that the two subspecies of A. semialata are among the most recently diverging lineages of C3 and C4 taxa currently recognized within the Panicoideae. Furthermore, the position of the C3 subspecies of A. semialata within the Alloteropsis genus is consistent with the hypothesis that its physiology represents a reversion from C4 photosynthesis. The data point to a similar evolutionary event in the Panicum stenodes–P. caricoides–P. mertensii clade. The Alloteropsis genus is monophyletic and occurs in a clade with remarkable diversity of photosynthetic biochemistry and leaf anatomy.ConclusionsThese results confirm the utility of A. semialata as a model system for investigating C3 and C4 physiology, and provide molecular data that are consistent with reversions from C4 to C3 photosynthesis in two separate clades. It is suggested that further phylogenetic and functional investigations of the Alloteropsis genus and closely related taxa are likely to shed new light on the mechanisms and intermediate stages underlying photosynthetic pathway evolution.

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Section: Discussionmentioning

confidence: 75%

Section: Introductionmentioning

confidence: 99%

A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

et al. 2008

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“…The two taxa were distinguished by comparing the leaf blades according to the guidelines of Gibbs Russell (1983), summarized as follows: Subspecies semialata has linear leaf blades, 3-5 (6) mm wide, usually curved upwards, tapering gradually to the tip and sparsely hairy. C4 anatomy manifests in veins on basal parts of the sheaths, forming broad flat ribs 0.5-l.lmm across and is visible with a hand lens.…”

Section: Morphologymentioning

confidence: 99%

Comparative cytogenetic investigation of the two subspecies of the grass Alloteropsis semialata (Poaceae)

Liebenberg

Fossey

2001

Botanical Journal of the Linnean Society

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A cytotaxonomic investigation was undertaken to assess the taxonomic status of the grasses Alloteropsis semialata subsp. eckloniana and A. semialata subsp. semialata, distinguished because of a C3 photosynthetic pathway in subsp. eckloniana and a C4 pathway in subsp. semialata. Of the 30 analysed specimens of population A, 14 (46.7%) were diploid, 14 (46.7%) hexaploid, one octoploid (3.3%) and one dodecaploid (3.3%). Of the 21 specimens of population B, 14 (66.7%) were diploid, three (14.3%) hexaploid and four (19.0%) octoploid. All the diploids belonged to subsp. eckloniana, while all the polyploids belonged to subsp. semialata. Meiosis of the diploids appeared normal, with nine bivalents and a mean metaphase I chiasma frequency of 12.7 per cell. The hexaploids displayed a large range of chromosome pairing associations, although a high percentage of bivalents was recorded (89.9%). Three of the hexaploids showed 100% bivalent pairing, but the largest multivalent found in other hexaploids was a hexavalent pairing. The three octoploids analysed had 93.5% bivalent pairing. B chromosomes were found in five diploids, two hexaploids and one octoploid. Slow‐moving bivalents, two in the diploids and up to four in the polyploids segregated late at anaphase I in most specimens.

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“…Alloteropsis semialata is a unique grass, including both Kranz and non‐Kranz leaf anatomies, and therefore C 3 and C 4 photosynthetic modes, within this one species (Ellis 1974a,b). Gibbs Russell (1983) re‐examined the taxonomic position of A. semialata by using vegetative characters and classified the Kranz and the non‐Kranz forms into the subspecies semialata and eckloniana , respectively. Previous studies on the photosynthetic characteristics of the two subspecies have demonstrated that the respective C 4 and C 3 characteristics correspond to the activities of photosynthetic enzymes, carbon isotope ratios and CO 2 gas exchange (Brown 1977; Barrett, Frean & Cresswell 1983; Frean, Ariovich & Cresswell 1983a; Frean et al .…”

Section: Introductionmentioning

confidence: 99%

“…Liebenberg & Fossey (2001) reported that in South Africa the distributions of the two subspecies overlap and they are growing in mixed populations. Although some authors doubt that the two photosynthetic forms constitute the same species (Liebenberg & Fossey 2001), it seems certain that they are taxonomically close (Gibbs Russell 1983).…”

Section: Introductionmentioning

confidence: 99%

Comparison of leaf structure and photosynthetic characteristics of C₃ and C₄Alloteropsis semialata subspecies

Ueno¹,

Shibata²

2005

Plant Cell & Environment

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Alloteropsis semialata (R. Br.) Hitchcock includes both C 3 and C 4 subspecies: the C 3 subspecies eckloniana and the C 4 subspecies semialata . We examined the leaf structural and photosynthetic characteristics of these plants. A. semialata ssp. semialata showed high activities of photosynthetic enzymes involved in phosphoenolpyruvate carboxykinasetype C 4 photosynthesis and an anomalous Kranz anatomy. Phosphoenolpyruvate carboxylase; pyruvate, Pi dikinase and glycine decarboxylase (GDC) were compartmentalized between the mesophyll (M) and inner bundle sheath cells, whereas ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) occurred in both cells. A. semialata ssp. eckloniana also showed an anomalous non-Kranz anatomy, in which the mestome sheath cells included abundant chloroplasts and mitochondria. Rubisco and GDC accumulated densely in the M and mestome sheath cells, whereas the levels of C 4 enzymes were low. The activity levels of photorespiratory enzymes in both subspecies were intermediate between those in typical C 3 and C 4 plants. The values of CO 2 compensation points in A. semialata ssp. semialata were within the C 4 range, whereas those in A. semialata ssp. eckloniana were somewhat lower than the C 3 range. These data suggest that the plants are C 3 -like and C 4 -like but not typical C 3 and C 4 , and when integrated with previous findings, point to important variability in the expression of C 4 physiology in this species complex. A. semialata is therefore an intriguing grass species with which to study the evolutionary linkage between C 3 and C 4 plants.

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The taxonomic position of C3 and C4 <i>Alloteropsis semialata</i> (Poaceae) in southern Africa

Cited by 20 publications

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A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

Comparative cytogenetic investigation of the two subspecies of the grass Alloteropsis semialata (Poaceae)

Comparison of leaf structure and photosynthetic characteristics of C₃ and C₄Alloteropsis semialata subspecies

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The taxonomic position of C3 and C4 <i>Alloteropsis semialata</i> (Poaceae) in southern Africa

Cited by 20 publications

References 0 publications

A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

A molecular phylogeny of the genus Alloteropsis (Panicoideae, Poaceae) suggests an evolutionary reversion from C4 to C3 photosynthesis

Comparative cytogenetic investigation of the two subspecies of the grass Alloteropsis semialata (Poaceae)

Comparison of leaf structure and photosynthetic characteristics of C3 and C4Alloteropsis semialata subspecies

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Comparison of leaf structure and photosynthetic characteristics of C₃ and C₄Alloteropsis semialata subspecies