Comparative Analysis and Phylogenetic Relationships of Ceriops Species (Rhizophoraceae) and Avicennia lanata (Acanthaceae): Insight into the Chloroplast Genome Evolution between Middle and Seaward Zones of Mangrove Forests

Complete chloroplast genomes of six neotropical palm species, structural comparison, and evolutionary dynamic patterns

The Arecaceae family has a worldwide distribution, especially in tropical and subtropical regions. We sequenced the chloroplast genomes of Acrocomia intumescens and A. totai, widely used in the food and energy industries; Bactris gasipaes, important for palm heart; Copernicia alba and C. prunifera, worldwide known for wax utilization; and Syagrus romanzoffiana, of great ornamental potential. Copernicia spp. showed the largest chloroplast genomes (C. prunifera: 157,323 bp and C. alba: 157,192 bp), while S. romanzoffiana and B. gasipaes var. gasipaes presented the smallest (155,078 bp and 155,604 bp). Structurally, great synteny was detected among palms. Conservation was also observed in the distribution of single sequence repeats (SSR). Copernicia spp. presented less dispersed repeats, without occurrence in the small single copy (SSC). All RNA editing sites were C (cytidine) to U (uridine) conversions. Overall, closely phylogenetically related species shared more sites. Almost all nodes of the phylogenetic analysis showed a posterior probability (PP) of 1.0, reaffirming the close relationship between Acrocomia species. These results elucidate the conservation among palm chloroplast genomes, but point to subtle structural changes, providing support for the evolutionary dynamics of the Arecaceae family.

Isolation and Evaluation of Cytotoxic, Anti-Inflammatory, Anti-Ulcer Activity of Methanolic Extract of Ceriops decandra leaves

The current study was undertaken to provide scientific validation for the traditional medicinal applications of Ceriops decandra leaves in treating gastrointestinal disorders and inflammation. Additionally, the study aimed to isolate a pure component from the extracted leaves for further analysis. Lupeol was extracted from the crude methanolic extract of Ceriops decandra leaves by column chromatography as part of a phytochemical inquiry. Its structure was determined using 1H and 13C NMR spectroscopy. In order to assess the cytotoxicity, the unrefined methanolic extract was divided into two fractions: a petroleum fraction and an aqueous fraction, employing the modified Kupchan method. The brine shrimp lethality test revealed that both the aqueous and petroleum ether fractions had significant cytotoxic activity, with LC50 values of 1.93 µg/l and 2.04 µg/l, respectively. These values were compared to the LC50 value of the standard Vincristine Sulphate, which was found to be 0.02 µg/l. The results of the anti-inflammatory trial demonstrated that the administration of the extract at doses of 250mg/kg and 500mg/kg resulted in protection rates of 62.5% and 87.5%, respectively, as compared to the carrageenan control group after 3 hours post-injection. It is worth noting that Ibuprofen exhibited a higher level of protection, with a rate of 91.7%. In the context of ethanol-induced stomach ulcer, the administration of extracts at doses of 250 mg/kg and 500 mg/kg resulted in 45.5% and 59.1% protection against gastric ulcer, respectively. These findings were compared to the protective effect of Omeprazole, which demonstrated 63.6% protection and served as the standard reference. The findings suggest that the methanolic leaf extract of Ceriops decandra possesses robust cytotoxic and potent anti-inflammatory and anti-ulcer properties. These results provide support for the traditional application of this extract in the management of gastrointestinal diseases, inflammation, and cancer.

Characterization of the complete chloroplast genome of Carallia brachiata (Lour.) Merr. (Rhizophoraceae)

Carallia brachiata (Lour.) Merr. (1919) is an important medical resource distributed across subtropical Asia. In this study, the complete chloroplast genome of C. brachiata was sequenced, revealing a total length of 162,460 bp, including four regions - a large single copy (89,814 bp), a small single copy (18,804 bp), and a pair of inverted repeats (26,921 bp each). The overall guanine + cytosine content was 35.76%. In total, 130 genes were annotated within the chloroplast genome, comprising 85 protein-coding, 37 tRNA, and 8 rRNA genes. Subsequent phylogenetic analyses revealed that C. brachiata is closely related to Carallia diplopetala.

The complete chloroplast genome of Ulmus mianzhuensis with insights into structural variations, adaptive evolution, and phylogenetic relationships of Ulmus (Ulmaceae)

BACKGROUND

Ulmus mianzhuensis is an endemic tree species in China with high ornamental and economic value. Currently, little is known regarding its genomic architecture, phylogenetic position, or adaptive evolution. Here, we sequenced the complete chloroplast genome (cp genome) of U. mianzhuensis and further compared the variations in gene organization and structure within Ulmus species to define their genomic evolution, then reconstructed the phylogenomic relationship of 31 related Ulmus species to explore the systematic position of U. mianzhuensis and the utility of cp genome for resolving phylogenetics among Ulmus species.

RESULTS

Our results revealed that all the Ulmus species exhibited a typical quadripartite structure, with a large single copy (LSC) region of 87,170 - 88,408 bp, a small single copy (SSC) region of 18,650 - 19,038 bp and an inverted repeat (IR) region of 26,288 - 26,546 bp. Within Ulmus species, gene structure and content of cp genomes were highly conserved, although slight variations were found in the boundary of SC/IR regions. Moreover, genome-wide sliding window analysis uncovered the variability of ndhC-trnV-UAC, ndhF-rpl32, and psbI-trnS-GCU were higher among 31 Ulmus that may be useful for the population genetics and potential DNA barcodes. Two genes (rps15 and atpF) were further detected under a positive selection of Ulmus species. Comparative phylogenetic analysis based on the cp genome and protein-coding genes revealed consistent topology that U. mianzhuensis is a sister group to U. parvifolia (sect. Microptelea) with a relatively low-level nucleotide variation of the cp genome. Additionally, our analyses also found that the traditional taxonomic system of five sections in Ulmus is not supported by the current phylogenomic topology with a nested evolutionary relationship between sections.

CONCLUSIONS

Features of the cp genome length, GC content, organization, and gene order were highly conserved within Ulmus. Furthermore, molecular evidence from the low variation of the cp genome suggested that U. mianzhuensis should be merged into U. parvifolia and regarded as a subspecies of U. parvifolia. Overall, we demonstrated that the cp genome provides valuable information for understanding the genetic variation and phylogenetic relationship in Ulmus.

Species richness, extent and potential threats to mangroves of Sarangani Bay Protected Seascape, Philippines

Mangroves form one of the most vital tropical ecosystems that support many species and surrounding communities. The Sarangani Bay Protected Seascape (SBPS) in the south of Mindanao Islands in the Philippines is home to a large number of mangrove species, which have not been fully explored. We updated the list of true mangrove species for SBPS from 10 to 24 by integrating the results of our survey and other past mangrove assessments. A practical spatial analysis approach was used to estimate the current mangrove forest extent of SBPS at 514 ha, as compared to 479 ha and 332 ha in 1998 and 2016, respectively, from other independent reports. Mangrove cover was negatively related to built area, cropland, bare ground, rangeland and total human population, but positively related to the number of fishing boats and total tree cover. In addition, we identified other potential anthropogenic threats to mangroves and categorised them into forest clearing or deforestation, over-extraction and pollution. The benefits of mangrove cover expansion, adoption of mangrove-friendly aquaculture and revitalising degraded mangrove forests outweigh their constraints. Our work provided a locally relevant understanding of the potential causes of mangrove loss and the values of human actions in mangrove dynamics, which will contribute to reliable and informed decision-making for the conservation of mangrove species and restoration of mangrove forests in SBPS.

The characteristics of the complete chloroplast genome of Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae)

Staurogyne concinnula (Hance) O. Kuntze (Acanthaceae) is an important ornamental herb mainly distributed in the southern region of China, including Fujian, Guangdong, Hainan, and Taiwan provinces. However, the complete chloroplast genome of S. concinnula, which could serve as a genetic resource for studies on its taxonomy and evolution, is poorly studied at present. In this study, we reported the complete chloroplast genome of S. concinnula that was assembled using high-throughput sequencing data. The chloroplast genome was 153,783 bp long, with a typical quadripartite structure containing a small single-copy region (SSC; 17,855 bp), a large single-copy region (LSC; 84,636 bp) and a pair of inverted repeats (IRs; each 25,646 bp). The overall GC content of the chloroplast genome was 38.04%. A total of 86 protein-coding genes (PCGs), 8 rRNA genes, and 37 tRNA genes were predicted. Phylogenetic analysis based on the combined sequences of 86 PCGs with the other 16 closely related species of Acanthaceae indicated that S. concinnula is closely related to Avicennia marina. The genomic data and finding from the phylogenetic studies of S. concinnula could provide useful information and give light to in-depth studies on the evolution pattern of the understudied species, as well as Staurogyne.

Characterization of the complete chloroplast genome of Carallia diplopetala (Rhizophoraceae)

Carallia diplopetala (Rhizophoraceae) is an important economic tree species narrowly distributed endemic to East Asia. In this study, We generate the complete chloroplast genome of C. diplopetala using next-generation sequencing technology, which is 162,052 bp in size and consists of a large single copy (LSC) of 89,556 bp and a small single copy (SSC) of 18,814 bp, separated a pair of inverted repeats (IRb and IRa) of 26,841 bp. The overall GC content is 36.4%. A total of 130 genes are annotated, including 83 protein-coding genes, 37 tRNAs, eight rRNAs and two pseudogenes (ψycf1 and ψrps19). The phylogenetic analysis indicated that C. diplopetala and C. brachiate formed a monophyletic clade with strong support and then sister to Pellacalyx yunnanensis. The plastome of C. diplopetala will provide informative genomic resources for further conservation applications.

The complete chloroplast genome of Sonneratia griffithii Kurz (Lythraceae)

Sonneratia griffithii Kurz is a critically endangered mangrove species that can be found along the western coast of Thailand. In this study, we reported the complete chloroplast genome of S. griffithii. The chloroplast genome is 152,730 bp, consisting of one large single-copy (LSC) region, one small single-copy (SSC) region and a pair of inverted repeats (IRs). The LSC, SSC, and IR lengths are 87,226, 17,764, and 23,870 bp, respectively. The genome contains 113 unique genes, including 79 protein-coding, 30 tRNA, and 4 rRNA genes. The GC content of the chloroplast genome is 37.31%. The phylogenetic analysis based on 76 protein-coding genes showed a monophyletic group of S. griffithii and other Sonneratia species.

Chromosome-level genome assembly of Indian mangrove (Ceriops tagal) revealed a genome-wide duplication event predating the divergence of Rhizophoraceae mangrove species

Mangrove ecosystems are unique, highly diverse, provide benefits to humans, and aid in coastal protection. The Indian mangrove, or spurred mangrove, [Ceriops tagal (Perr.) C. B. Rob.] is a member of the Rhizophoraceae family and is commonly found along the intertidal zones in tropical regions in Southeast Asia, southern Asia, and Africa. Here, we present the first high-quality reference genome assembly of the Ceriops species. A preliminary draft assembly, generated from the 10× Genomics linked-read library, was scaffolded using the proximity ligation chromatin contact mapping technique (Hi-C) to obtain a chromosome-scale assembly of 231,919,005 bases with an N50 length of 11,408,429 bases. The benchmarking universal single-copy orthologs (BUSCO) analysis revealed that C. tagal gene predictions recovered 95.8% of the highly conserved orthologs. Phylogenetic analyses suggested that C. tagal diverged from the last common ancestor of flat-leaf spurred mangrove [C. decandra (Griff.) Ding Hou] and C. zippeliana Blume ∼10.4 million yr ago (MYA), and the last common ancestor of genera Ceriops, Kandelia, and Rhizophora diverged from that of genus Bruguiera ∼49.4 MYA. In addition, our analysis of the transversion rate at fourfold-degenerate sites from orthologous gene pairs provided evidence supporting a recent whole-genome duplication in C. tagal. The STRUCTURE and principal component analyses illustrated that C. tagal individuals investigated in this study were the admixture of two subpopulations, the genetic background of which was influenced primarily by location. The availability of genomic and transcriptomic resources and biodiversity data reported in this work will be useful for future studies that may shed light on adaptive evolutions of mangrove species.