Transcriptome Analysis of Salt Stress in Hibiscus hamabo Sieb. et Zucc Based on Pacbio Full-Length Transcriptome Sequencing

Hibiscus hamabo Sieb. et Zucc is an important semi-mangrove plant with great morphological features and strong salt resistance. In this study, by combining single molecule real time and next-generation sequencing technologies, we explored the transcriptomic changes in the roots of salt stressed H. hamabo. A total of 94,562 unigenes were obtained by clustering the same isoforms using the PacBio RSII platform, and 2269 differentially expressed genes were obtained under salt stress using the Illumina platform. There were 519 differentially expressed genes co-expressed at each treatment time point under salt stress, and these genes were found to be enriched in ion signal transduction and plant hormone signal transduction. We used Arabidopsis thaliana (L.) Heynh. transformation to confirm the function of the HhWRKY79 gene and discovered that overexpression enhanced salt tolerance. The full-length transcripts generated in this study provide a full characterization of the transcriptome of H. hamabo and may be useful in mining new salt stress-related genes specific to this species, while facilitating the understanding of the salt tolerance mechanisms.

Pesticidal Activity of Sundarban Mangrove Plant Extracts against Sitophilus Pests and Identification of Active Constituents Using LC-MS

Plants act as a rich source of novel natural pesticides. In the backdrop of the recent revival of interest in developing plant-based insecticides, this study was carried out to investigate the pesticidal activity of Sundarban mangrove plants. A total of nine different plant parts from five plants, namely, Aegiceras corniculatum, Excoecaria agallocha, Heritiera fomes, Xylocarpus moluccensis, and Xylocarpus granatum, were extracted with methanol and tested for insecticidal activity against two common stored product pests Sitophilus oryzae and Sitophilus zeamais using direct contact feeding deterrent wafer disc method. Three bark extracts from A. corniculatum, E. agallocha, and H. fomes showed potent and statistically significant insecticidal activity against both S. oryzae and S. zeamais pests (80–100% mortality). All the active bark extracts were further fractionated using C-18 solid-phase extraction (SPE) columns and tested for their insecticidal activity against S. oryzae pest to identify the active fraction. Only the SPE4 fraction (100% MeOH) from all the three active plants showed the activity against S. oryzae pest with a lethal concentration 50% (LC50) value of 0.5, 1.0, and 1.5 mg/disc for A. corniculatum, E. agallocha, and H. fomes, respectively. The active fraction of A. corniculatum was further profiled for identification of active compounds using LC-ESI-MS and identified (along with some unknown peaks) two previously reported compounds at m/z 625.17630 (isorhamnetin 3-O-rutinoside) and 422.25346 (paspaline) as major constituents. Insecticidal activities of these plants are reported in this study for the first time and would be useful in promoting research aiming for the development of new biopesticides from mangrove plants.

Antioxidant and Anti-inflammatory Activities of Different Solvent Extracts from Ipomoea pes-caprae (L.) R. Br. in Lipopolysaccharide Stimulated RAW 264.7 Macrophages

The oxidative stress and inflammatory environment trigger an unhealthy circle, which can lead to various inflammatory diseases. Ipomoea pes-caprae, a traditional medicine mangrove plant, posed many pharmacological activities, including antioxidant, anti-inflammatory and anticancer effects. However, the possible mechanisms involved in Ipomoea pes-caprae are still unclear. This study aimed to investigate the antioxidant and anti-inflammatory effects of different solvent extracts from Ipomoea pes-caprae on lipopolysaccharide (LPS) stimulated macrophages. Three different solvent gradients were prepared orderly from non-polar to polar: hexane (Hex), supercritical fluid extraction using carbon dioxide plus EtOH as co-solvent (SCO2) and ethanol (EtOH). All 3 extracts were screened for the cytotoxicity on RAW264.7 cells by MTT assay. The non-toxic doses were investigated for reactive oxygen species (ROS) scavenging by DPPH and DCFH-DA assays and evaluated their anti-inflammatory activities via inhibition against LPS-induced nitric oxide (NO), prostaglandin E2 (PGE2), inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression. All 3 extracts (25 - 50 μg/mL) exhibited DPPH scavenging and reduced intracellular ROS level in the order of SCO2 > EtOH > Hex. Further, these extracts suppressed NO and PGE2 production by regulating iNOS and COX-2 mRNA expression in the order of SCO2 > Hex > EtOH. Additionally, their inhibitory effects were in a similar pattern as the standard drugs L-NAME and celecoxib. These findings support the traditional use of Ipomoea pes-caprae in treating inflammatory diseases due to its attenuation of inflammation in activated macrophage. Also, a wide range of secondary metabolites in unique ecology may be useful as one of the alternative therapies for inflammatory diseases. HIGHLIGHTS Ipomoea pes-caprae employ a sort of secondary metabolites under stressful high salt conditions with benefit for new drug discoveries SCO2 extract exhibited the strongest activities in the LPS-induced ROS and PGE2 production These bioactive compounds contained in Ipomoea pes-caprae confirm the traditional use against jellyfish stings and may targeting inflammatory pathways GRAPHICAL ABSTRACT

Hydraulic architecture of seedlings and adults of Rhizophora mangle L. in fringe and scrub mangrove

Background: Mangrove plant species have distinctive anatomical and physiological responses to cope with a wide range of salinities and inundations. These strategies pertain a safe and efficient water use and transport, essential for survival. Questions: How are the anatomical and physiological attributes of the hydraulic architecture of seedlings and adults of Rhizophora mangle? what are the changes in hydraulic architecture of seedlings and adults of R. mangle in contrasting microenvironments? Studied species: Rhizophora mangle L. (Rhizophoraceae). Study site and dates: Scrub and fringe mangroves in Ria Celestún Biosphere Reserve, during the rainy season of 2013 (July to October). Methods: Hydraulic conductivity and leaf water potential, as well as xylem vessel density, length, transversal and radial diameter, and area were measured for seedlings and adults from both sites. The prevailing environmental conditions (soil water potential, salinity, photon flux density, air temperature and relative humidity) were also characterized. Results: A safer hydraulic conduction system, with narrow and more grouped vessels, was observed in seedlings than in adults of R. mangle in both sites. Adult individuals from the scrub mangrove, in the hyper saline microenvironment, had a safer hydraulic conduction system than adults in the fringe mangrove. Conclusions: The seedling stage of R. mangle showed a safer hydraulic system than adults in both types of mangroves. However, over time this hydraulic conduction system could become more efficient or remain safe depending on the microenvironment in which individuals are growing.

Mangrove’s Plant: An updated Review on Ethnobotanical, Phytochemical and Pharmacological Potential of Barringtonia racemosa

The conventional usages and traditions of people in Barringtonia racemosa (L.) (B. racemosa) mangrove plant species in their day-to-day life and therapeutic techniques. B. racemosa (L.) belongs to family Barringtoniaceae, with single-seeded, oval-shaped fruit and a tall tree dispersed in India's east and west coasts. B. racemosa (L.), titled as putat, a fish poison tree or powder puff tree, is a precious plant species due to its medicinal values. Its fruit pulp is used in fish poison and diarrhea, asthma, coughs, analgesic and antipyretic, and has significant antitumor activity. Flavonoids and phenolic acids are the primary metabolites of the leaves and are used to reduce hypertension and purgative. In addition, the pulverized leafage, barks, and roots are used to lessen the inflammation and chickenpox. Among the phenolic compounds specified in the leaves of B. racemosa (L.) include ferulic acid, naringin, gallic acid, rutin, luteolin, protocatechuic acid, kaempferol, quercetin, and ellagic acid. Conventional remedial practices have the whole plant as a therapy for itch; the antimalarial activity is reported in roots. The bark or leaf are used in abscesses, sores, serpent bites, rat poisonings, gastric ulcers, hypertension, chickenpox. In contrast, the kernels or seeds are sourced for carcinogenic disorders and eye inflammation. The current review emphasized the ethnobotanical, phytochemistry and pharmacological activities of B. racemosa (L.) proved through various scientific facts.

Pharmacological Properties, Volatile Organic Compounds, and Genome Sequences of Bacterial Endophytes from the Mangrove Plant Rhizophora apiculata Blume

Mangrove plant endophytic bacteria are prolific sources of bioactive secondary metabolites. In the present study, twenty-three endophytic bacteria were isolated from the fresh roots of the mangrove plant Rhizophora apiculata. The identification of isolates by 16S rRNA gene sequences revealed that the isolated endophytic bacteria belonged to nine genera, including Streptomyces, Bacillus, Pseudovibrio, Microbacterium, Brevibacterium, Microbulbifer, Micrococcus, Rossellomorea, and Paracoccus. The ethyl acetate extracts of the endophytic bacteria’s pharmacological properties were evaluated in vitro, including antimicrobial, antioxidant, α-amylase and α-glucosidase inhibitory, xanthine oxidase inhibitory, and cytotoxic activities. Gas chromatography–mass spectrometry (GC-MS) analyses of three high bioactive strains Bacillus sp. RAR_GA_16, Rossellomorea vietnamensis RAR_WA_32, and Bacillus sp. RAR_M1_44 identified major volatile organic compounds (VOCs) in their ethyl acetate extracts. Genome analyses identified biosynthesis gene clusters (BGCs) of secondary metabolites of the bacterial endophytes. The obtained results reveal that the endophytic bacteria from R. apiculata may be a potential source of pharmacological secondary metabolites, and further investigations of the high bioactive strains—such as fermentation and isolation of pure bioactive compounds, and heterologous expression of novel BGCs in appropriate expression hosts—may allow exploring and exploiting the promising bioactive compounds for future drug development.

Effects of Mangrove Plant Extraction on Adhesion Strength in Coating of Epoxy

Steel is an alloy of ferrous metal with a maximum carbon content of 2%. This material is widely used for jetty building structures at rivers, estuary, and coastal areas. Corrosion of steel can occur due to several factors, such as the steel material itself and the surrounding environmental factors. One of the corrosion is biocorrosion that occurs due to the presence of biofouling. This study aims to determine the effect of adding extraction of mangrove (Avicennia marina) as an antifouling compound mixed in epoxy paint through adhesion strength parameter. Then the alloy was applied as a coating on the ASTM A36 steel specimen. The variation of coating composition were 100% of epoxy paint, 90%:10% (epoxy paint and extraction of Avicennia marina), 80% : 20% and 70% : 30%. The results showed that the adhesion strength occurred in 100% of epoxy paint (10.15 ± 0.64 Mpa). The adhesion strength was 8.86 ± 0.21 Mpa, 8.50 ± 0.03 Mpa, and 8.19 ± 0.07 Mpa at ratio of composition coating 90%: 10%, 80%: 20%, and 70%: 30%, respectively. In conclusion, the more mangrove extraction was added, the smaller the adhesion strength.

Evaluation of Antioxidant and Anticorrosive Activities of Ceriops tagal Plant Extract

Mangroves are plants known for their various medicinal and economical values, and therefore are widely investigated for their phytochemical, antioxidant, antidiarrheal, and antimicrobial activities. In the present study, we analyze the antioxidant and anticorrosive properties of Ceriops tagal (C. tagal), a tropical and subtropical mangrove plant of the Rhizophoraceae family. The total phenolic content (TPC) and total flavonoid content (TFC) were found to be 101.52 and 35.71 mg/g, respectively. The extract (100 µg/mL) exhibited 83.88, 85, and 87% antioxidant property against 1,1-diphenyl-2-picrylhydrazyl (DPPH), nitric oxide, and hydrogen peroxide free radicals. In addition, 600 ppm of C. tagal extract showed 95% corrosion inhibition against 1 M HCl attack on mild steel at 303 ± 1 K, which declined over other concentrations and temperatures, where AAS produced 82% inhibition at 600 ppm. UV-visible spectroscopy analysis revealed the formation of an inhibitor metal complex. The elemental analysis provided the presence of 84.21, 9.01, and 6.37% of Fe, O, and C, respectively, in inhibited mild steel, whereas the same were 71.54, 22.1, and 4.34%, respectively, in uninhibited specimen, stressing the presence of protective film on the metal surface. Scanning electron microscopy (SEM) also showed some noteworthy changes in both uninhibited and inhibited mild steel, making C. tagal plant a better alternative than any other synthetic inhibitors. Further, the atomic force microscopy (AFM) surface topography analysis showed that 600 ppm of C. tagal extract significantly diminished corrosion on the surface of mild steel.