title: Phylogeny and photosynthetic pathway distribution in Anticharis Endl. (Scrophulariaceae).
abstract: C(4) photosynthesis independently evolved >62 times, with the majority of origins within 16 dicot families. One origin occurs in the poorly studied genus Anticharis Endl. (Scrophulariaceae), which consists of ~10 species from arid regions of Africa and southwest Asia. Here, the photosynthetic pathway of 10 Anticharis species and one species from each of the sister genera Aptosimum and Peliostomum was identified using carbon isotope ratios (δ(13)C). The photosynthetic pathway was then mapped onto an internal transcribed spacer (ITS) phylogeny of Anticharis and its sister genera. Leaf anatomy was examined for nine Anticharis species and plants from Aptosimum and Peliostomum. Leaf ultrastructure, gas exchange, and enzyme distributions were assessed in Anticharis glandulosa collected in SE Iran. The results demonstrate that C(3) photosynthesis is the ancestral condition, with C(4) photosynthesis occurring in one clade containing four species. C(4) Anticharis species exhibit the atriplicoid type of C(4) leaf anatomy and the NAD-malic enzyme biochemical subtype. Six Anticharis species had C(3) or C(3)-C(4) δ(13)C values and branched at phylogenetic nodes that were sister to the C(4) clade. The rest of Anticharis species had enlarged bundle sheath cells, close vein spacing, and clusters of chloroplasts along the centripetal (inner) bundle sheath walls. These traits indicate that basal-branching Anticharis species are evolutionary intermediates between the C(3) and C(4) conditions. Anticharis appears to be an important new group in which to study the dynamics of C(4) evolution.
authors.affiliation: Department of Plant Sciences, School of Biology, College of Sciences, University of Tehran PO Box 14155-6455, Tehran  Iran.
authors.forename: Roxana
authors.initials: R
authors.lastname: Khoshravesh
authors.forename: Akhani
authors.initials: A
authors.lastname: Hossein
authors.forename: Tammy L
authors.initials: TL
authors.lastname: Sage
authors.forename: Bertil
authors.initials: B
authors.lastname: Nordenstam
authors.forename: Rowan F
authors.initials: RF
authors.lastname: Sage
mesh_terms: D005075:Biological Evolution; D053898:Biosynthetic Pathways; D002247:Carbon Isotopes / Q000032:analysis; D002736:Chloroplasts / Q000201:enzymology / Q000648:ultrastructure; D018548:Cotyledon / Q000033:anatomy & histology / Q000378:metabolism; D018744:DNA, Plant / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D005843:Geography; D007150:Immunohistochemistry; D008291:Malate Dehydrogenase / Q000378:metabolism; D010641:Phenotype; D010730:Phosphoenolpyruvate Carboxylase / Q000378:metabolism; D010788:Photosynthesis / Q000502:physiology*; D010802:Phylogeny; D018515:Plant Leaves / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D010940:Plant Proteins / Q000378:metabolism*; D018526:Plant Transpiration; D012273:Ribulose-Bisphosphate Carboxylase / Q000378:metabolism; D028083:Scrophulariaceae / Q000201:enzymology / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D017422:Sequence Analysis, DNA
chemical_list: D002247:Carbon Isotopes; D018744:DNA, Plant; D021903:DNA, Ribosomal Spacer; D010940:Plant Proteins; D008291:Malate Dehydrogenase; C046446:malate dehydrogenase-(oxaloacetate-decarboxylating) (NAD+); D010730:Phosphoenolpyruvate Carboxylase; D012273:Ribulose-Bisphosphate Carboxylase