J Syst Evol

05 September 2012, Volume 50 Issue 5

Cover illustration: The Caryophyllales are a major eudicots lineage with a traditionally challenging evolutionary history. They possess diverse biological traits, including carnivory, drought and salt tolerance, and a variety of photosynthetic pathways. Sequence information from rapidly evolving plastid matK gene and trnK intron provides strong phylogenetic signal and a robust phylogeny for the Caryophyllales. Cover displays representatives of Caryophyllales life forms: Center—Persicaria bistorta; clockwise from top [Detail] ...

Research Articles

Caryophyllales: Evaluating phylogenetic signal in trnK intron versus matK

Sunny S. CRAWLEY, Khidir W. HILU

J Syst Evol. 2012, 50(5): 387-410.
https://doi.org/10.1111/j.1759-6831.2012.00197.x

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We assess the phylogenetic information in trnK intron at the ordinal level using the Caryophyllales and compare it with that derived from matK. The trnK gene is split into two exons by an intron that includes the matK gene. The plastid trnK is a tRNA gene encoding Lysine^(UUU), whereas the matK gene is a putative group II intron maturase. The two regions are usually coamplified, and trnK intron is partially sequenced but its sequences are often excluded from phylogenetic reconstruction at deep historic levels. This study shows that the two regions are comparable in proportion of variable sites, possess a comparable pattern of substitution rates per site, and display similar phylogenetic informativeness profiles and per-site informativeness. Phylogenetic analyses show strong congruence between phylogenetic trees based on matK and trnK intron partitioned datasets from 45 genera representing 30 of the 34 recognized Caryophyllales families. The trnK intron alone provides a relatively well-resolved topology for the order. Combining the trnK intron with matK sequence data resulted in six most parsimonious trees, differing only in the placement of Claytonia (Portulacaceae) within the noncore group. A well-supported major basal split in the order into core and noncore Caryophyllales with Rhabdodendraceae, Simmondsiaceae, and Asteropeiaceae as sister to remaining core lineages is evident in partitioned and combined analyses. The placement of these three families has been disputable, impacting the overall backbone topology of the Caryophyllales. This study demonstrates the cost effectiveness of using the trnK intron along with matK (both substitutions and insertions/deletions) at deeper phylogenetic level.
North-south population subdivision of Juniperus seravschanica in Kyrgyzstan revealed through novel plastid DNA markers

Ormon SULTANGAZIEV, Heino KONRAD, Silvio SCHUELER, Thomas GEBUREK

J Syst Evol. 2012, 50(5): 411-421.
https://doi.org/10.1111/j.1759-6831.2012.00206.x

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Junipers are main components of semiarid forests in Central Asia. Conservation of these plant genetic resources should be based on an understanding of factors that have shaped species-level genetic variation. We used Juniperus seravschanica Kom. as a model species to investigate patterns and processes that may be associated with these factors. Novel plastid DNA markers (two minisatellites, one transversion, one indel) were identified and applied to investigate haplotype diversity and population structure in Kyrgyzstan. In total, 540 individuals from 15 populations were analyzed and 11 haplotypes detected. Strong divergence between populations from northern and southern Kyrgyzstan was evident from the haplotype distribution. Gene diversity within populations ranged from 0.083 to 0.765, and was on average higher in southern (0.687) than in northern populations (0.540). A similar pattern was detected in allelic richness. Analysis of molecular variance (AMOVA) revealed that 11.9% of the total genetic variation was due to differences among regions, 1.5% among populations, and 86.6% within populations. N_ST was not significantly different from G_ST (0.125), suggesting no evidence of a phylogeographic pattern. A Mantel test detected a weak but significant isolation-by-distance pattern for the whole dataset and southern populations separately. These results suggest that the north of Kyrgyzstan was relatively recently colonized by migrants from southern populations, probably associated with favorable conditions during the early Holocene. The humid Fergana Valley and Fergana Range are probable ecological barriers to gene flow between northern and southern populations.
Molecular phylogeny of Ficus section Ficus in China based on four DNA regions

Hong-Qing LI, Shuang WANG, Ji-Yun CHEN, Ping GUI

J Syst Evol. 2012, 50(5): 422-432.
https://doi.org/10.1111/j.1759-6831.2012.00221.x

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We carried out molecular phylogenetic analyses to examine the phylogenetic relationship of Ficus section Ficus (Moraceae) based on 22 species, 73 samples of the section, and 37 species, 41 samples representing other sections of Ficus. Four DNA sequences from the nuclear ribosomal internal transcribed spacer and the plastid trnH-psbA, psbK-psbI, and atpF-atpH intergenetic regions were selected. Phylogenetic analyses using maximum parsimony, maximum likelihood, and Bayesian methods revealed that section Ficus was not monophyletic unless subsection Ficus was removed and that subsection Frutescentiae was monophyletic when excluding species such as F. tikoua Bureau, F. pedunculosa Miq., and F. neriifolia Sm. Ficus tikoua should be transferred from subgenus Ficus to subgenus Sycomorus. Ficus tuphapensis Drake should be transferred into subsection Frutescentiae from section Eriosycea. Our results also supported the placement of F. henryi Warb. ex Diels and F. subincisa Buch.-Ham. ex Sm. in subgenus Sycidium.
Richness and diversity of Leguminosae in an altitudinal gradient in the tropical semi-arid zone of Brazil

Jacira R. LIMA,Vidal F. MANSANO, Francisca S. ARAÚJO

J Syst Evol. 2012, 50(5): 433-442.
https://doi.org/10.1111/j.1759-6831.2012.00190.x

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Many studies are based on the premise that, on a local scale, diversity is the result of ecological processes, whereas on a regional scale factors such as the topography, geology, hydrology, and historical and evolutionary events would influence this control. The Baturité Mountain Range (Ceará state), located in the Brazilian semi-arid zone, is considered an area of extreme importance for conservation with its vegetation varying with the altitude and slope (windward vs. leeward). On the windward (wet) slope, rainforest dominates, whereas the leeward (dry) slope is dominated by seasonal forests and thorny woodland. The aim of this study was to contribute to the knowledge of the patterns of richness and diversity of the family Leguminosae on a local scale (Baturité Mountain Range) as well as a regional scale (northeastern Brazil). The two slopes present quite distinct floras. The dry slope presents higher richness and diversity indices for Leguminosae than the wet slope. The highest diversity of Leguminosae in the dry areas did not corroborate the ideas of other studies carried out in neotropical forests (total flora) that the higher species richness was predicted for wet areas. The present study indicates that the historical and evolutionary processes influence the diversity patterns on a local scale (Baturité Mountain Range), as well as on a regional scale (Brazilian semi-arid). Our results reinforce the uniqueness of each portion of this area and its importance for conservation.
Limited divergence among populations of rice striped stem borer in southeast China caused by gene flow: Implications for resistance management

Chao YANG, Xiao YANG, Qiang FU, Kai XU, Bao-Rong LU

J Syst Evol. 2012, 50(5): 443-453.
https://doi.org/10.1111/j.1759-6831.2012.00202.x

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Rice striped stem borer (RSSB, Chilo suppressalis) is a serious lepidopteron pest occurring in rice ecosystems of Asia and Europe. Genetically modified (GM) insect-resistant Bt rice has been developed to deter lepidopteron pests including RSSB. The concern of resistance evolution to the Bt toxin by the pests under commercial cultivation of GM Bt rice and the need of effective management of the resistance encourage the studies of genetic variation and divergence, as well as gene flow of RSSB populations. We analyzed 13 RSSB populations fed on water-oats or rice plants, respectively, from southeast China applying the fluorescent amplified fragment length polymorphism fingerprints. A generally moderate level of genetic variation was detected in the populations, as estimated by Nei's genetic diversity (0.27) and Shannon's index (0.42). The F_ST and amova values indicated a low level (∼12%) of genetic divergence among the RSSB populations. A relatively frequent gene flow (an average Nm = 2.62) was detected among the 12 RSSB populations, which may explain the limited genetic divergence among the rice-feeding populations. This explanation gains support by the assignment test of the corresponding populations, suggesting that a considerable proportion of individuals was contributed from non-native populations. Our results revealed that the moderate level of genetic diversity combined with relatively frequent gene flow among RSSB populations across a large geographical range may slow down the resistance evolution of the RSSB populations, given that a proper measure of resistance management is taken.
Effects of soil moisture and floral herbivory on sexual expression in a gynodioecious orchid

Yang LU, Yi-Bo LUO, Shuang-Quan HUANG

J Syst Evol. 2012, 50(5): 454-459.
https://doi.org/10.1111/j.1759-6831.2012.00195.x

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Compared to pollinator limitation and inbreeding avoidance, the role of ecological factors in sexual differentiation has received less attention in sexual dimorphic plants. The effect of soil moisture and florivory on two sexual morphs in a gynodioecious orchid, Satyrium ciliatum, was investigated in seven gynodioecious (with both female and hermaphrodite individuals) and 15 hermaphroditic (with only hermaphrodite individuals) populations. Our result showed that, compared to hermaphrodites, females tended to occur in drier sites in which soil water content was consistently lower than that of hermaphrodites in all gynodioecious populations. The soil water content where hermaphrodites grew was not significantly different between gynodioecious and hermaphroditic populations. We observed that females experienced less attack by insect florivores than hermaphrodites in gynodioecious populations, and hermaphroditic populations had higher insect attack than gynodioecious populations. Our results provide evidence for females being favored in stressful sites. However, the soil moisture and degree of florivory were not correlated to female frequency among populations, suggesting that the two ecological factors have not induced strong effects or other factors that may also influence the sex ratio in the facultative apomictic orchid.
Chromosome studies in the tribe Clauseneae and the cytological homogeneity in the orange subfamily (Aurantioideae, Rutaceae)

Feng-Juan MOU, Dian-Xiang ZHANG

J Syst Evol. 2012, 50(5): 460-466.
https://doi.org/10.1111/j.1759-6831.2012.00193.x

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Chromosome numbers for 21 Rutaceous species, representing five genera (Bergera, Clausena, Glycosmis, Micromelum, and Murraya) in the tribe Clauseneae (Aurantioideae, Rutaceae) were investigated to shed light on the relationships between these genera in the tribe in particular, and with other groups in the orange subfamily in general. Most species have the chromosome number 2n= 2x= 18, but Glycosmis shows variable chromosome numbers with ploidy levels ranging from 2x to 8x. Glycosmis parviflora is hexaploid with a chromosome number of 2n= 6x= 54 and G. longipetala octoploid with 2n= 8x= 72, and diploid with 2n= 2x= 18 was observed in other species. One species (Clausena excavata) shows intraspecies ploidy variation. The chromosome numbers of 11 species, Bergera kwangsiensis, B. microphylla, Clausena dunniana, C. emarginata, C. lenis, C. yunnanensis, Glycosmis esquirolii, G. lucida, G. oligantha, Micromelum falctum, and Murraya alata, are reported for the first time. The basic chromosome number x= 9 was inferred for all species studied. These results, together with previous chromosome counts in the tribe Citreae, reveal a cytological homogeneity, and strongly support the monophyly of the orange subfamily.
Foonchewia guangdongensis gen. et sp. nov. (Rubioideae: Rubiaceae) and its systematic position inferred from chloroplast sequences and morphology

Hai-Zhen WEN, Rui-Jiang WANG

J Syst Evol. 2012, 50(5): 467-476.
https://doi.org/10.1111/j.1759-6831.2012.00196.x

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The new species, Foonchewia guangdongensis R. J. Wang & H. Z. Wen and the new monotypic genus Foonchewia R. J. Wang (Rubioideae, Rubiaceae), are described from eastern Guangdong, China. It is characterized by its subshrub habit, pentamerous and heterostylous flowers, 2-1ocular ovary with many ovules, and apically dehiscent capsules with numerous angulated seeds. Phylogenetic analysis of four chloroplast DNA regions (rbcL, rps16, ndhF, and atpB-rbcL) revealed that the new genus is nested in the Spermacoceae alliance and is sister to Dunnia. Morphological comparison between these two genera indicated that they had few synapomorphies; it was therefore inappropriate to classify the new genus in the existing tribe Dunnieae, and a new tribe, Foonchewieae R. J. Wang, is accordingly proposed.