Plumbaginaceae from saudi arabia using its sequences of nuclear ribosomal dna
Fig. 4- Strict Consensus Tree inferred using PAUP 4.0b
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Fig. 4- Strict Consensus Tree inferred using PAUP 4.0b
A T C G A - 2.56 1.86
29 T 1.7 - 14.48
2.55 C 1.7 19.87 - 2.55 G 19.31
2.56 1.86
- Table 6- Characteristics of ITS sequences of nuclear ribosomal DNA in the taxon sequenced in the present study Taxon ITS1 5.8 ITS2 Total ITS length Length
%GC Length
%GC Length
%GC Limonium axillare 613
202 50
163 50
248 49
Limonium carnosum 615
201 45
161 48
247 51
Limonium cylindrifolium 618
202 50
163 50
253 48
Limonium lobatum 599
203 46
161 53
233 50
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118 Fig. 5- Bootstrap Strict Consensus Tree inferred using PAUP 4.0b Fig. 6- NJ Tree inferred using PAUP 4.0b Discussion Plumbaginaceae are a cosmopolitan family well represented in temperate zones of the Northern Hemisphere and showing prefer- ences for arid or saline, often coastal, environments [47]. The Angi- osperm Phylogeny Group classification of flowering plants [3] in- cluded them in a broadly defined order Caryophyllales, together with other families adapted to extreme environments including oli- gotrophic soils (e.g., Droseraceae), arid zones (e.g., Cactaceae and Portulacaceae), and soils with high salt content (e.g., Amaranthace- ae and Tamaricaceae). Phylogenetic studies of Plumbaginaceae based on plastid DNA sequences and morphological data have been produced recently [48]. These studies confirmed the classifi- cation of Plumbaginaceae into two subfamilies, Plumbaginoideae and Staticoideae, well differentiated by morphological, chemical, and molecular characters. Plumbaginoideae comprise four genera, of which Plumbago, with approximately 20 species, is the largest. Staticoideae are morphologically more diverse. More than 85% of the species are in three genera, Limonium, Armeria, and Acantho- limon, and the remaining species belong to monotypic or small gen- era split from Limonium and Acantholimon, although the status of these genera is not clear yet, as [47] pointed out. Recent systematic and phylogenetic studies of Limonium lack a global perspective, having been based on specific geographic areas [5,49] or individual sections or groups that are putatively monophyletic [50]. The latest comprehensive accounts for the family and Limonium were pub- lished by [6], and later authors have followed his system with only small alterations. Boissier divided Limonium former Statice, nom.
‘‘corolla polypetala’’ with eight sections and ‘‘corolla gamopetala’’ with four sections plus two others published at a later date. Only two sections of the original corolla gamopetala, L. sect. Polyarthrion and L. sect. Siphonantha, are still included in Limonium, although phylogenetic relationships of these new genera to other members of Staticoideae have not yet been assessed. Within the corolla poly-
The most recent attempt to clarify the taxonomy of Limonium was made by [52] who rearranged the genus for Flora Europaea. Pignat- ti divided the European taxa in three subgenera. Limonium subge- nus Pteroclados (equivalent to the section with the same name) has approximately 18 species mostly endemic to the Canary Islands. Limonium subgenus Myriolepis was created to include three sec- tions (L. sects. Myriolepis, Siphonantha, and Polyarthrion), all of them members of Boissier’s corolla gamopetala group. Finally, placed the remainder of the European sections in a large unstruc- tured L. subgenus Limonium, leaving African, American, and Asiatic species out of his system. In addition, nomenclature of the genus is also obsolete. Most of the sectional names were originally pub- lished under the former generic name Statice. Although some names have been consequently combined under Limonium (e.g., for European groups), a large number of sections are still based on dubious nomenclature. Despite the systematic and taxonomic confusion around Limonium and Plumbaginaceae in general, two aspects of the family, breeding systems and phytochemistry, are better known. Phytochemical studies [53,54] have confirmed the differences between subfamilies and among Southern and Northern Hemisphere groups. Neverthe- less, the lack of a robust systematic and phylogenetic framework makes interpretation of these results speculative. Breeding systems International Journal of Molecular Biology ISSN: 0976-0482 & E-ISSN: 0976-0490, Volume 6, Issue 1, 2015 Al-Ghanem S.M.S.
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119 were extensively studied by [55,56], who has been influential in the development of evolutionary and biogeographical hypotheses for the family, including the dispersal of genera related to Limonium to the southern continents (Afrolimon, Bakerolimon, and Muellero-
tems, and karyology), [56]) made the first attempt to clarify relation- ships among genera and tribes in the family. [56] results were obvi- ously limited by the amount and types of data available at that time, and in the light of new molecular data these have been shown to be only partially correct [48]. [56] also studied the evolution of Limoni- um in more detail. Heterostyly, although typical in Plumbaginoideae, is also present in L. subsect. Genuinae [55], whereas pollen/stigma dimorphism and self-incompatibility, common within Staticoideae, are widespread in Limonium. Facultative apomixis is common in Limonium, whereas truly sexual species are infrequent (e.g., L. sects. Polyarthrion and Pteroclados); sexual groups usually display fewer species than the apomictic ones. Hybridization, apomixis, and polyploidy in L. subsects. Densiflorae, Dissitiflorae, and Steiro- cladae are putatively key factors in the radiation of Limonium in areas such as the western Mediterranean basin. As a conse- quence, a large number of microspecies have been described, making difficult attempts to clarify the taxonomy of the group [57]. One of the advantages of constructing molecular trees is the possi- bility of estimating the ages of lineages. The calibration of molecular trees is usually based on the fossil record or specific events that can be dated e.g., presence of lineages on oceanic islands [58]. Plumbaginaceae have not been the focus of any extensive fossil research, and even pollen records are restricted to Quaternary stra- ta [59]. Despite the lack of fossil information, the presence of phylo- genetically isolated lineages on a volcanic archipelago, the Canary Islands, can be used as a calibration point. The Canary Islands are too close to the African continent to behave as a truly oceanic archi- pelago (110 km for the closest island, Fuerteventura, and 460 km for the most distant island, La Palma). The geomorphology of the Canary Islands has been extensively studied, as well as biogeogra- phy and colonization patterns [60]. The archipelago was formed by a series of volcanic periods that started approximately 20 million years ago (mya). There are three groups of Limonium present in the island flora, of which L. sect. Pteroclados and L. sect. Ctenostachys are not exclusive to the Islands. The monotypic and morphologically atypical L. sect. Limoniodendron (L. dendroides), which is a small tree or shrub only found on La Gomera, does not seem to be close- ly related to any other taxa. This island, formed approximately 10 mya [60], is the only island in the archipelago that has been without major volcanic activity for the last 4 million years. The age of the island can be used as a reasonable minimal age for L. dendroides to calibrate the tree, assuming that the intervening volcanic activity did not eliminate the flora. In Limonium, polyploidy and apomixis are common, numerous hy- brids occur naturally, and, as a consequence, reticulate evolution seems to be the rule rather than the exception. Sizes of ITS-1 and ITS-2 in the Limonium species studied were similar to those report- ed for other flowering plants, with ITS-1 longer than ITS-2 [18]. In
which conforms to other studies on closely related plants [18]. The conservation of ITS sequences is presumably due to their role in the production of mature rRNA, and this functionality depends on evolutionarily conserved secondary structural motifs. Inference of nonindependence at directly opposing sites in these secondary structures can be determined empirically [61]. However; in the pre- sent study, differential character weights for stem vs loop positions did not lead to different results in the analysis of ITS sequences from Limonium. It has been demonstrated that rRNA processing mechanisms could be labile enough to allow readjustments of in- trastrand RNA pairing, which could imply mutations at nonpaired positions [62]. This pattern of substitutions could have important implications for phylogenetic analysis but it could also mean that selection for compensatory mutations might be weaker for these spacers than for nrDNA coding regions, alleviating the concern about nonindependence of characters [63]. The analysis of ITS using parsimony methods of phylogenetic reconstruction has re- vealed a relatively stable phylogenetic structure [64,65]. In the pre- sent study, the relationships obtained among Limonium ITS se- quences using ML, NJ, and parsimony approaches are, in general, congruent for well-supported groups. Palacios et al [66] have detected intraspecific polymorphism in spe- cies of Limonium with two molecular markers, RFLPs of chloroplast DNA and nrDNA ITS sequences. L. furfuraceum, a sexual species with a very conspicuous morphology but no variability was found in its rDNA. L. delicatulum represents another case in which intraspe- cific variability has been detected but with an opposite rDNA-cpDNA pattern of variability. A similar explanation has also earlier been suggested for ITS polymorphism in other plant species [67]. In some cases, conspecific samples rendered identical genotypes; in others, intraspecific variability has been detected through pooled DNA samples from different individuals of the same population. These phenomena should prevent reporting these ITS sequences as unique sequences, representative of the corresponding species. In the present analyses taxon were included from 1. Sect. Limonium Subsections Densiflorae, 2. Sect. Limonium Subsections Steiro- cladae, 3. Sect. Limonium Subsections Hyalolepidae, 4. Sect. Limo- nium Subsections Limonium, 5. Sect. Limonium Subsections Dissiti- florae, 6. Sect. Polyarthrion, 7. Sect. Schizhymenium. In the present study, Limonium axillare, L. cylndrifolium, L. carnosum, and L. loba-
395. 1891. (5 Nov 1891), Synonym= Statice axillaris Forssk. Peltier, M. 1981. Plombaginacées. Fl. Madagasc. 163: 15-23; Statice bovei Jaub. & Spach. Peltier, M. 1981. Plombaginacées. Fl. Madagasc. 163: 15-23], is in Arabic known as Qataf, is distributed in Tropical Africa, Egypt, and Costal region on the red sea in Saudi Arabia; which have been characterized as: a costal small shrub up to c. 50 cm tall; leaves fleshy, alternate, lamina oblanceolate to oblanceo- late-spathulate, 3-8 mm wide, tapering to amplexicaul base, inflo- rescence a panicle of one sided spikes bearing few flowered cymes; bracts and bracteoles reddish, the bracteoles c. 2.5 mm long; calyx tube c. 2 mm long, the limb c. 4 mm across, calyx tube plicate, papery membranous, white with reddish ribs, the ribs pu- bescent at base, corolla purplish red, crumpling. Limonium cylndrifolium (Forssk) O. Kuntze, [rev Gen. Pl 2: 395 (1891); Synonym= Stice cylindrifolium Forssk (1753)], is distributed in Ethiopia, Yemen, and Red sea coast and island, Farsan Island near Ras Hassis in Saudi Arabia, have been morphologically char- acterized as: acostal perennial herb up to c. 50 cm tall, old branch- es covered with whitish, spirally arranged remnants of bases of fallen-off leaves; leaves cylindrical, up to c. 6 cm long, 1.5-2 mm across, mucronate; flowers in few flowered cymes densely arranged in one sided spikes forming racemes or panicles on leafless space; bracteoles up to c. 3.75 mm long, reddish brown; calyx up to c. 3.25 International Journal of Molecular Biology ISSN: 0976-0482 & E-ISSN: 0976-0490, Volume 6, Issue 1, 2015 Phylogenetic Relationship Studies on the Genus Limonium Mill. Plumbaginaceae from Saudi Arabia Using its Sequences of Nuclear Ribosomal DNA
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120 mm long, hardly projecting above the bracteoles; calyx tube c. 2 mm long, glabrous, not pubescent along the ribs; corolla deep red- dish projecting about 1 mm beyond calyx, crumpled within calyx on drying up, stamens exserted.
(1891); synonym= Statice carnosa Boiss (1848)], is in Arabic known as Qataf or Awaidhan, and distributed in Eastern region or at the margins of costal marshes of Saudi Arabia, and Iran; have been morphologically characterized as: perennial, ascending to erect, much branched undershrub up to c. 40 cm tall; branches thin, lower leafy, the scapose leafless with only small bracts, mostly warty with foviate pustular glands; leaves densely foveolate-pustular, alter- nate, rather densely arranged, linear spathulate, up to 3 cm long and up to 3 mm at the top, tapering downwards into thin petiole like basal parts which expand to form membranous edged, amplexicaul bases; flowers pink, in few to several flowered, dense, cymose, shortly pedunculate or sessile, axillary clusters arranged on leafless branches of paniculate spaces; bracts foveolate pustular at the least in the median region; bracteoles up to c. 2 mm long; calyx c. 3 mm long, pink, glabrous or sparsely pubescent basally along some of the ribs; corolla c. 4.5 mm long, pink or white, becoming crumped and inconspicuous at the base of calyx. Limonium lobatum (L. f.) Chaz. [Dict. Jard. 2:36(1790) plate 172; synonym= Staice thouinii Viv., (1802); S. lobata L. f. (1782); Limoni- um thouinii Kuntze (1891)] is patchily seen in silty soils of Saudi Arabia, known in Arabic as Kitaah sibsab, have been characterized as: annual, stiff herb up to c. 25 cm tall with several erect scapes from a basal rosette of leaves; scapes simple or branched, 3 winged in the upper nodes; leaves sessile or subsessile, oblanceo- late to spathuate, up to 8 x 2 cm, branched, pinnately lobed into usually 3-4 pairs; the lobes rounded, usually 3-4 pairs; flowers in few-several flowered dense cymes subtended by broadly 3-winged obconical branches of the scape, the whole acting as a disseminule and falling off together; bracteoles 2-keeled at back, up to c. 6 mm long; calyx silvery white to pale blue c. 4 mm long, lobes 5, about as long as the tube, alternating with 5, prominent bristles, coyellowish, crumpling up. The analyses clearly reveals that the largest section of the genus (section Limonium) does not constitute a monophyletic assemblage.
um and L. axillare which has been previously placed in Sect. Limo- nium, Subsections Limonium doesnot nested within its clade of own, rather were found base of the phylogenetic tree. Limonium lobatum which has been previously based on morphology have been placed in Section Pteroclados, subsection Pdontolepideae, occupied basal most position in the pylogenetic tree. In the absence of a previous phylogenetic analysis of section Limo- nium based on other independent characters [48], [66] discussed the results only in relation to the classification of the group, which is based mainly on morphological and karyological characters [6,5], and find out that the splitting of section Limonium does not agree with the results of the phylogenetic analyses of nuclear and orga- nellar markers. suggested that the largest section of the genus (section Limonium) does not constitute a monophyletic assemblage. The basal position of the two analyzed species of subsection Limo- nium (L. vulgare and L. narbonense) was strongly supported in all analyses. The same results were obtained using rbcL sequences with five Limonium species. Levels of sequence divergence suggest that molecular differentiation between taxa of subsection Limonium and the other species from section Limonium is larger than ex- pected based on exomorphic features. In addition, morphological and anatomical data suggest that subsection Limonium is a group of well-knit species not linked by intermediates to the remaining section Limonium. This agrees with results based on anatomical and morphological proposed that subsections Densiflorae and Dissitiflorae should be merged. Nevertheless, Limonium taxa be- longing to these four subsections are apomictic and, presumably, have a hybrid origin from ancestors belonging to either subsection [67].
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