TY - JOUR

T1 - Phylogeny and photosynthetic pathway distribution in Anticharis Endl. (Scrophulariaceae)

AU - Khoshravesh, Roxana

AU - Akhani, Hossein

AU - Sage, Tammy L

AU - Nordenstam, Bertil

AU - Sage, Rowan F

PY - 2012/9/30

Y1 - 2012/9/30

N2 - 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.

AB - 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.

KW - Biological Evolution

KW - Biosynthetic Pathways

KW - Carbon Isotopes/analysis

KW - Chloroplasts/enzymology

KW - Cotyledon/anatomy & histology

KW - DNA, Plant/chemistry

KW - DNA, Ribosomal Spacer/chemistry

KW - Geography

KW - Immunohistochemistry

KW - Malate Dehydrogenase/metabolism

KW - Phenotype

KW - Phosphoenolpyruvate Carboxylase/metabolism

KW - Photosynthesis/physiology

KW - Phylogeny

KW - Plant Leaves/enzymology

KW - Plant Proteins/metabolism

KW - Plant Transpiration

KW - Ribulose-Bisphosphate Carboxylase/metabolism

KW - Scrophulariaceae/enzymology

KW - Sequence Analysis, DNA

U2 - 10.1093/jxb/ers218

DO - 10.1093/jxb/ers218

M3 - Journal article

C2 - 22945938

VL - 63

SP - 5645

EP - 5658

JO - Journal of Experimental Botany

JF - Journal of Experimental Botany

SN - 0022-0957

IS - 15

ER -