Comparative Chloroplast Genomes of Zosteraceae Species Provide Adaptive Evolution Insights Into Seagrass

Seagrasses are marine flowering plants found in tropical and sub-tropical areas that live in coastal regions between the sea and land. All seagrass species evolved from terrestrial monocotyledons, providing the opportunity to study plant adaptation to sea environments. Here, we sequenced the chloroplast genomes (cpGenomes) of three Zostera species, then analyzed and compared their cpGenome structures and sequence variations. We also performed a phylogenetic analysis using published seagrass chloroplasts and calculated the selection pressure of 17 species within seagrasses and nine terrestrial monocotyledons, as well as estimated the number of shared genes of eight seagrasses. The cpGenomes of Zosteraceae species ranged in size from 143,877 bp (Zostera marina) to 152,726 bp (Phyllospadix iwatensis), which were conserved and displayed similar structures and gene orders. Additionally, we found 17 variable hotspot regions as candidate DNA barcodes for Zosteraceae species, which will be helpful for studying the phylogenetic relationships and interspecies differences between seagrass species. Interestingly, nine genes had positive selection sites, including two ATP subunit genes (atpA and atpF), two ribosome subunit genes (rps4 and rpl20), two DNA-dependent RNA polymerase genes (rpoC1 and rpoC2), as well as accD, clpP, and ycf2. These gene regions may have played key roles in the seagrass adaptation to diverse environments. The Branch model analysis showed that seagrasses had a higher rate of evolution than terrestrial monocotyledons, suggesting that seagrasses experienced greater environmental pressure. Moreover, a branch-site model identified positively selected sites (PSSs) in ccsA, suggesting their involvement in the adaptation to sea environments. These findings are valuable for further investigations on Zosteraceae cpGenomes and will serve as an excellent resource for future studies on seagrass adaptation to sea environments.

Effects of rhizome and root trimming on the growth and survival of Phyllospadix iwatensis transplants: a case study in Shandong Peninsula, China

Surfgrass Phyllospadix iwatensis has been declining in the past decades. Transplantation is considered to be the best option to restore the degraded surfgrass beds due to its low seed production. To develop a surfgrass transplanting strategy to increase transplant survival rate and also to minimize damage to donor beds when harvesting transplants, an experiment was conducted to assess the effects of rhizome and root trimming on transplant survival and growth. P. iwatensis shoots with different rhizome and root trimming treatments were planted in a subtidal area in Mashanli at the east end of Shandong Peninsula, China in September 2018, and after the transplantation, a bi-monthly sampling had been conducted for one year. The results showed that, at the early stage of transplantation, the transplant survival rates of all four treatment groups decreased to the lowest at four months after transplantation, and then gradually increased until reaching at least 103.2% in all the treatment groups at the end of the experiment, and the transplants with roots on both short and long rhizomes had a significantly higher survival rate than those without roots. The results also showed that, although the morphological measurements, as well as the above- and below-ground productivity varied greatly with time and among different treatments during the study period, most of them showed no significant differences between treatments at the end of the experiment. These results suggest that surfgrass shoots with roots and a short rhizome are the most strongly recommended transplant candidates, and those with a short rhizome without roots are also good candidates, which might help make full use of harvested plants, optimize transplant harvesting strategies, and hence minimize damage to donor meadows.

A refuge for threatened sea grasses (Zostera asiatica Miki and Phyllospadix iwatensis Makino) at the islands Iturup and Urup of Kuril archipelago

Survey of sea grasses at the coasts of Urup and Iturup islands of Kuril archipelago has been fulfilled. Three species have been found – Zostera marina L., Zostera asiatica Miki and Phyllospadix iwatensis Makino. The last two species are of particular interest as they are threatened and distributed over relatively small area. Unlike the habitats of the main part of their range located at the coasts of Japan and Korea, the habitats of the studied islands do not suffer from anthropogenic pressure. The discovered northern refuge is significant for the sea grasses conservation. Current global warming and increasing anthropogenic pressure on the southern habitat would increase its significance.

Разработка и оценка качества сухого концентрата напитка на основе модифицированного пектина с добавлением женьшеня и элеутерококка

Разработана технология и рецептура сухого концентрата напитка, содержащего функциональные ингредиенты: модифицированный пектин из Phyllospadix iwatensis, гинсенозиды, элеутерозиды и аскорбиновую кислоту. Определены дозы всех ингредиентов с учетом норм суточного потребления. Исследован процесс гранулирования композиции пектина и сахарозы с добавлением настойки женьшеня и экстракта элеутерококка. Содержание пектина, гинсенозидов, элеутерозидов и аскорбиновой кислоты в однократной дозировке напитка (10 г) составляет 100% от адекватного суточного уровня потребления каждого из данных ингредиентов. Проведена органолептическая оценка напитка и определены его основные физико-химические показатели. The technology for producing dry concentrate for a functional beverage based on the modified pectin from the sea grass Phyllospadix iwatensis added with ginseng tincture and eleutherococcus extract is described in the article. To classify the beverage as a functional one, we used a composition containing 20% pectin. The quantitative content of the total ginsenosides (in terms of ginsenoside Rg1) was defined by the spectrophotometric method at a wavelength of 526 nm. The eleutheroside B and ascorbic acid quantity was defined by HPLC with spectrophotometric detection at 270 nm and 243 nm, respectively. To improve the organoleptic characteristics, citric acid and stevioside were added to the beverage. The beverage formula was developed in accordance with the requirements of the State Standard of Russia number 28188-2014 and with the norms of the daily consumption. The content of pectin, ginsenosides, eleutherosides and ascorbic acid in a unit dosage of the drink (10 g) is 100% of the adequate daily intake of each of these ingredients. The organoleptic evaluation of the drink was carried out in accordance with ISO 11035: 1994 and the State Standard of Russia number 6687.5-86. The basic physical -chemical indicators (titrated acidity, humidity, mass fraction of dry substances and minerals) were determined.

Luteolin 7-Sulfate Attenuates Melanin Synthesis through Inhibition of CREB- and MITF-Mediated Tyrosinase Expression

Antioxidants with antimelanogenic activity are potentially useful for the attenuation of skin hyperpigmentation disorders. In a previous study, luteolin 7-sulfate isolated from Phyllospadix iwatensis Makino, a marine plant, was shown to inhibit cellular melanin synthesis. The aim of the present study was to examine its action mechanism, focusing on the regulation of tyrosinase (TYR) expression in cells. Cell-based assay was undertaken using murine melanoma B16-F10 cells and primary human epidermal melanocytes (HEMs). Luteolin 7-sulfate showed lower toxicity compared to luteolin in B16-F10 cells. At the non-toxic concentration ranges, luteolin 7-sulfate attenuated melanin synthesis, stimulated by α-melanocyte-stimulating hormone or forskolin. Luteolin 7-sulfate attenuated forskolin-induced microphthalmia-associated transcription factor (MITF) and TYR expressions at the mRNA and protein levels in B16-F10 cells. It also attenuated the phosphorylation of cAMP-responsive element binding protein (CREB) stimulated by forskolin. Luteolin 7-sulfate also attenuated melanin synthesis in primary HEMs. This study demonstrates that luteolin 7-sulfate attenuates TYR gene expression through the intervention of a CREB- and MITF-mediated signaling pathway, leading to the decreased melanin synthesis.

The Phyllospadix iwatensis community in the intertidal zone of the Far Eastern seas of Russia

The community of Phyllospadix iwatensis is studied using materials from expeditions of A.V. Zhirmunsky Institute of Marine Biology (National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences) and archive data (1949-2013) of the Laboratory of Chorology covering the species habitat area from Peter the Great Bay in the south to middle Kuril Islands in the north. The core of the community is identified. It has changing species composition; the changes correspond to geographical boundaries of the cenotic systems of Peter the Great Bay, the Lesser Kuril Islands, and Iturup Island. However, these boundaries do not coincide with the boundaries of the species-edificator habitat that embraces several cenotic systems. Spatial alterations of the cenotic systems are caused by landscape changes conditioned by general geomorphological situation and ecological conditions in the intertidal zone.

A new species of seagrass-boring Limnoria (Limnoriidae, Isopoda, Crustacea) from Japan

The marine seagrass-boring isopod, Limnoria rhombipunctata sp. nov. (Limnoriidae) is described from the rhizome of Phyllospadix iwatensis seagrass, in shallow coastal waters off Chiba Prefecture, Japan. L. rhombipunctata sp. nov. is distinguished from other Limnoria species by the unique carinae of pleonite 5 and pleotelson, two branched lacinia mobilis of the right mandible, 3 flagellar articles of antenna 1, and triangular epipod of the maxilliped. Specimens of L. magadanensis, a species similar to L. rhombipunctata sp. nov., are re-examined and compared with L. rhombipunctata sp. nov.