Background: The plastome of medicinal and endangered species in Kingdom of Saudi Arabia, Barleria prionitis was sequenced. The plastome was compared with that of seven Acanthoideae species in order to describe the plastome, spot the microsatellite, assess the dissimilarities within the sampled plastomes and to infer their phylogenetic relationships. Results: The plastome of B. prionitis was 152,217 bp in length with Guanine-Cytosine and Adenine-Thymine content of 38.3 and 61.7% respectively. It is circular and quadripartite in structure and constitute of a large single copy (LSC, 83, 772 bp), small single copy (SSC, 17, 803 bp) and a pair of inverted repeat (IRa and IRb 25, 321 bp each). 131 genes were identified in the plastome out of which 113 are unique and 18 were repeated in IR region. The genome consists of 4 rRNA, 30 tRNA and 80 protein-coding genes. The analysis of long repeat showed all types of repeats were present in the plastome and palindromic has the highest frequency. A total number of 98 SSR were also identified of which mostly were mononucleotide Adenine-Thymine and are located at the non coding regions. Comparative genomic analysis among the plastomes revealed that the pair of the inverted repeat is more conserved than the single copy region. In addition high variation is observed in the intergenic spacer region than the coding region. The genes, ycf1and ndhF and are located at the border junction of the small single copy region and IRb region of all the plastome. The analysis of sequence divergence in the protein coding genes indicates that the following genes undergo positive selection (atpF, petD, psbZ, rpl20, petB, rpl16, rps16, rpoC, rps7, rpl32 and ycf3). Phylogenetic analysis indicated sister relationship between Ruellieae and Justcieae. In addition, Barleria, Justicia and Ruellia are paraphyletic, suggesting that Justiceae, Ruellieae, Andrographideae and Barlerieae should be treated as tribes. Conclusions: This study sequenced and assembled the first plastome of the taxon Barleria and reported the basics resources for evolutionary studies of B. prionitis and tools for phylogenetic relationship studies within the core Acanthaceae.

The complete chloroplast genome of J. flava, an endangered medicinal plant in Saudi Arabia, was sequenced and compared with cp genome of three Acanthaceae species to characterize the cp genome, identify SSRs, and also detect variation among the cp genomes of the sampled Acanthaceae. NOVOPlasty was used to assemble the complete chloroplast genome from the whole genome data. The cp genome of J. flava was 150, 888bp in length with GC content of 38.2%, and has a quadripartite structure; the genome harbors one pair of inverted repeat (IRa and IRb 25, 500bp each) separated by large single copy (LSC, 82, 995 bp) and small single copy (SSC, 16, 893 bp). There are 132 genes in the genome, which includes 80 protein coding genes, 30 tRNA, and 4 rRNA; 113 are unique while the remaining 19 are duplicated in IR regions. The repeat analysis indicates that the genome contained all types of repeats with palindromic occurring more frequently; the analysis also identified total number of 98 simple sequence repeats (SSR) of which majority are mononucleotides A/T and are found in the intergenic spacer. The comparative analysis with other cp genomes sampled indicated that the inverted repeat regions are conserved than the single copy regions and the noncoding regions show high rate of variation than the coding region. All the genomes have ndhF and ycf1 genes in the border junction of IRb and SSC. Sequence divergence analysis of the protein coding genes showed that seven genes (petB, atpF, psaI, rpl32, rpl16, ycf1, and clpP) are under positive selection. The phylogenetic analysis revealed that Justiceae is sister to Ruellieae. This study reported the first cp genome of the largest genus in Acanthaceae and provided resources for studying genetic diversity of J. flava as well as resolving phylogenetic relationships within the core Acanthaceae.

Background: The loss of biodiversity in Nigeria is escalating alarmingly. However, there is generally a paucity of information as to what taxa are endangered because of a dearth of functioning conservation agencies in Nigeria. Objectives: The aim of this research is to record the endangered medicinal and other economic plant species in the Sudan Savanna vegetation in Katsina and to provide an assessment of the various threats faced by these plants. Method: Medicinal plants were identified through oral interviews with traditional medical practitioners within the study area. Conservation statuses were assessed using a bespoke data collection and assessment form; the data were then evaluated using the International Union for the Conservation of Nature Red List categories and criteria. Results: A total of 169 species belonging to 62 families were recorded. Of these, 43 taxa were reported to be used for ethnomedicinal practices. It was found that more than half (108) of the 169 species were threatened with extinction and one taxon (Xeroderris stuhlmannii [Taub.] Mendonca & Sousa) qualifies as being Extinct locally. Threats recorded include overexploitation (24%), agriculture (15%), deforestation and desertification (12% each), invasive plants (11%), urban residential development (7%) and erosion (6%). Conclusion: Most of the plants are already under threat and require urgent conservation measures. The data point to the critical need for further research into conservation strategies and a more sustainable use of threatened plants. We recommend that the Nigerian government should establish a national Red List agency and ensure effective protected area management and community-based natural resources management.

This study presents for the first time the complete chloroplast genomes of four medicinal species in the Capparaceae family belonging to two different genera, Cadaba and Maerua (i.e., C. farinosa, C. glandulosa, M. crassifolia and M. oblongifolia), to investigate their evolutionary process and to infer their phylogenetic positions. The four species are considered important medicinal plants, and are used in the treatment of many diseases. In the genus Cadaba, the chloroplast genome ranges from 156,481 bp to 156,560 bp, while that of Maerua ranges from 155,685 bp to 155,436 bp. The chloroplast genome of C. farinosa, M. crassifolia and M. oblongifolia contains 138 genes, while that of C. glandulosa contains 137 genes, comprising 81 protein-coding genes, 31 tRNA genes and 4 rRNA genes. Out of the total genes, 116–117 are unique, while the remaining 19 are replicated in inverted repeat regions. The psbG gene, which encodes for subunit K of NADH dehydrogenase, is absent in C. glandulosa. A total of 249 microsatellites were found in the chloroplast genome of C. farinosa, 251 in C. glandulosa, 227 in M. crassifolia and 233 in M. oblongifolia, the majority of which are mononucleotides A/T found in the intergenic spacer. Comparative analysis revealed variable hotspot regions (atpF, rpoC2, rps19 and ycf1), which can be used as molecular markers for species authentication and as regions for inferring phylogenetic relationships among them, as well as for evolutionary studies. The monophyly of Capparaceae and other families under Brassicales, as well as the phylogenetic positions of the studied species, are highly supported by all the relationships in the phylogenetic tree. The cp genomes reported in this study will provide resources for studying the genetic diversity of Capparaceae, as well as resolving phylogenetic relationships within the family.

The genus Mentha encompasses mint species cultivated for their essential oils, which are formulated into a vast array of consumer products. However, the systematics of the genus Mentha is very complicated and still uncertain. This is largely because of the presence of frequent interspecific hybridization, variation in chromosome number, cytomixis, polymorphism in morphology and essential oil composition under different environmental conditions, colonial mutant propagation, as well as the occurrence of polyploidy, aneuploidy, and nothomorphs. Here, we present the plastome assemblies for a wilt-resistant Saudi Arabian accession of Mentha longifolia (L.) Huds and an alien hybrid Mentha × verticillata L. which are 152,078 bp and 152,026 bp in length, respectively, and exhibited large single-copy (LSC) and small single-copy (SSC) regions separated by a pair of inverted repeat regions. The chloroplast genome of M. longifolia has 133 annotated genes, including 88 protein-coding genes and 37 tRNAs while M. × verticillata has 133 annotated genes, including 87 protein-coding genes and 38 tRNAs. Both cp genomes have eight rRNA genes. Phylogenetic analysis using a total chloroplast genome DNA sequence of 17 species revealed that M. longifolia sequenced in this study did not form a sister relationship with M. longifolia from another study. This opens a window for further investigations.