The present investigation includes in silico sequence analysis, structure prediction and phylogeny of Glutamine Synthetase from freshwater bony fishes. The analyses were performed for the sequence data of three glutamine synthetase genes namely gs01, gso2 and gso3 and their translated Gutamine Synthetase enzymes (GS-I, GS-II and GS-III). The evolutionary analyses were performed using Maximum Likelihood and Maximum Parsimony methods. The structures of Gutamine Synthetase were predicted using the template of Crystal Structure of Human Glutamine Synthetase (PDB ID: 2OJW). The computed instability index (40.60 to 46.96) classifies GS of M. albus as unstable. After verification, the structures of GS have been deposited to Protein Model Database (PMDB). The predicted structures of GS could be of use for further evaluation of molecular mechanism of function.

In Saudi Arabia, the family Plumbaginaceae is represented by two species: Limonium and Plumbago. The genus Limonium is represented by four species (i.e. Limonium axillare, L. carnosum, L. cylindrifolium, and L. lobatum). Out of these L. carnosum is endemic to Saudi Arabia. A perusal of taxonomic literature on Limonium reveals that the molecular evolutionary relationships of the species of Limonium distributed in Saudi Arabia is lacking. Owing to enormous phylogenetic significance of internal transcribed spacer sequence (ITS) of nuclear ribosomal DNA [-a gene which is now a day considered as better than its reputation, this study was undertaken with a aim to establish evolutionary relationships of the genus Limonium distributed in Saudi Arabia based on nrDNA ITS nucleotide sequences. The combined length of the entire ITS region (ITS1, 5.8S and ITS2) from taxa sequenced in the present study ranged from 599-618 nucleotides. The length of the ITS1 region and GC contents ranged from 201-203 nucleotides and 45-50% respectively, the 5.8S gene was 161- 163 nucleotides long, the length of the ITS2 region and the GC content ranged from 233-253 nucleotides and 48-51% respectively. The aligned data matrix has a total number of 670 characters of which 256 characters were constant, 255 characters were variable but parsimony-uninformative and 159 characters were parsimony-informative. Insertions and deletions (indels) were necessary to align the sequences. Indels ranged from 1 to 52 bp. In the present study, Limonium axillare, L. cylndrifolium, L. carnosum, and L. lobatum were sequenced, and analysed together with the taxon from 1. Sect. Limonium Subsections Densiflorae, 2. Sect. Limonium Subsections Steirocladae, 3. Sect. Limonium Subsections Hyalolepidae, 4. Sect. Limonium Subsections Limonium, 5. Sect. Limonium Subsections Dissitiflorae, 6. Sect. Polyarthrion, 7. Sect. Schizhymenium. The parsimony analysis (using PAUP) of the entire ITS region resulted in to 1280 maximally parsimonious trees (MPTs) with a total length of 480 steps, a consistency index (CI) of 0.754 (0.730) excluding uninformative characters), a homoplasy index (HI) of 0.456 (0.432 HI excluding uninformative characters), rescaled consistency index (RC) of 0.579 and a retention index (RI) of 0.767. The resulted phylogenetic tree clearly reveals that the largest section of the genus (section Limonium) does not constitute a monophyletic assemblage. Limonium carnosum clade with Limonium narbonense and Limonium vulgare (Sect. Limonium, Subsections Limonium); L. cylindrifolium and L. axillare which has been previously placed in Sect. Limonium, 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 phylogenetic tree. A perusal of all trees (Strict Consensus Tree, Bootstrap Strict Consensus Tree and NJ tree) clearly indicates that Limonium carnosum included in this study from geographic region Saudi Arabia, phylogenetically very closely related with Limonium narbonense and Limonium vulgare. It is also clearly evident that L. cylindrifolium and L. axillare does not nested deeply within the phylogenetic tree, rather were found at the base of the phylogenetic tree and L. lobatum occupies most basal position in phylogenetic tree. Limonium cylindrifolium and Limonium axillare shows sister relationships; however, in ITS sequences both these two species differs in 5 base pairs addition in ITS2 region. Therefore, ITS2 secondary structure for these two species, and additionally all taxon included in the analysis were predicted to bring molecular morphological signature of the Limonium distributed in Saudi Arabia. This is the first report of inferring the nrDNA ITS based phylogenetic relationships and establishment of molecular signature of the Limonium distributed in Saudi Arabia. Since, the majority of the species of the genus Limonium is yet to be sequence; the present study will nevertheless help in bringing the complete phylogeny of the genus.