Sugar Signals and R2R3-MYBs Participate in Potassium-Repressed Anthocyanin Accumulation in Radish.

Anthocyanin biosynthesis in plants is influenced by a wide range of environmental factors, such as light, temperature and nutrient availability. In this study, we revealed that the potassium-repressed anthocyanin accumulation in radish hypocotyls was associated with altered sugar distribution and sugar signaling pathways rather than changes in oxidative stress status. Sugar-feeding experiments suggested a hexokinase-independent glucose signal acted as a major contributor in regulating anthocyanin biosynthesis, transport and regulatory genes at the transcriptional level. Several R2R3-MYBs were identified as anthocyanin-related MYBs. Phylogenetic and protein sequence analyses suggested that RsMYB75 met the criteria of subgroup 6 MYB activator, while RsMYB39 and RsMYB82 seemed to be a non-canonical MYB anthocyanin activator and repressor, respectively. Through yeast-one-hybrid, dual-luciferase and transient expression assays, we confirmed that RsMYB39 strongly induced the promoter activity of anthocyanin transport-related gene RsGSTF12, while RsMYB82 significantly reduced anthocyanin biosynthesis gene RsANS1 expression. Molecular models are proposed in the discussion, allowing speculation on how these novel RsMYBs may regulate the expression levels of anthocyanin-related structural genes. Together, our data evidenced the strong impacts of potassium on sugar metabolism and signaling and its regulation of anthocyanin accumulation through different sugar signals and R2R3-MYBs in a hierarchical regulatory system.

A graphene/Janus B2P6 heterostructure with a controllable Schottky barrier via interlayer distance and electric field.

Lowering the Schottky barrier at the metal-semiconductor interface remains a stern challenge in the field of field-effect transistors. Herein, an in-depth investigation was conducted to explore the formation mechanism of the Schottky barrier via interlayer distance and external electric field, utilizing the first-principles approach. Attributed to the vertical asymmetric structure of B2P6, ohmic contact forms at the interface of a graphene/B2P6(001) heterostructure, and an n-type Schottky contact with a Schottky barrier of 0.51 eV forms at the interface of a graphene/B2P6(001̄) heterostructure. Furthermore, the Schottky barrier height and the contact type can be changed by adjusting the interlayer spacing or applying an electric field along the Z direction. A high carrier concentration of 4.65 × 1013 cm-2 is obtained in the graphene/B2P6(001) heterostructure when an external electric field of 0.05 V Å-1 is applied. Verifiably, alterations in the energy band structure are attributed to the redistribution of charges at the interface. The new findings indicate that GR/B2P6 heterostructures are a key candidate for next-generation Schottky field-effect transistor development.

Taxonomic identification and life cycle comparison of two populations of the monostromatic green algae Monostroma nitidum.

Monostroma nitidum, a monostromatic green algae (MGA) with high economic value, is distributed worldwide. Life cycle often serves as a fundamental criterion for taxonomic classification. Most researchers consider the life cycle of M. nitidum to involve dimorphic alternation of generations, although the possibility of a monomorphic asexual life cycle remains unclear. In this study, tufA and 18S rDNA sequences were employed as molecular markers, complemented by morphological analysis, to classify and identify MGA in two distinct habitats: Hailing Island reefs (YJ) and Naozhou Island reefs (ZJ). The results of tufA and 18S rDNA sequence analysis revealed that all samples from YJ and ZJ clustered to the same branch (M. nitidum clade) with high bootstrap support and genetic distances of less than 0.000 and 0.005, respectively. However, morphological observations indicated significant differences in the external morphology of the YJ and ZJ samples, although both initially exhibited a filament-blade form during early development. The life cycle of the ZJ samples exhibited typical dimorphic alternation of generations, whereas the YJ samples only produced biflagellate asexual gametes with negative phototaxis. Gametes of the YJ samples directly developed into new gametophytes without undergoing the sporophyte stage. Consequently, the YJ and ZJ samples were classified as monomorphic asexual and dimorphic sexual M. nitidum, respectively. These findings provide evidence supporting the monomorphic asexual life cycle of M. nitidum for the classification of MGA.

Multi-omics analysis provides insights intro lysine accumulation in quinoa (Chenopodium quinoa Willd.) sprouts.

Lysine, the first limiting essential amino acid, the deficiency of which seriously affects the health of human and animals. In this study, quinoa germination significantly increased the nutrients, especially lysine content. To better understanding the underlying molecular mechanism of lysine biosynthesis, isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomics, RNA-sequencing (RNA-Seq) technology and liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) platform-based phytohormones analyses were conducted. Through proteome analyses, a total of 11,406 differentially expressed proteins were identified, which were mainly related to secondary metabolites. The lysine-rich storage globulins and endogenous phytohormones probably contributed the increased lysine content in quinoa during germination. Furthermore, aspartic acid semialdehyde dehydrogenase is essential for lysine synthesis in addition to aspartate kinase and dihydropyridine dicarboxylic acid synthase. Protein-protein interaction analysis indicated lysine biosynthesis is associated with "amino metabolism" and "starch and sucrose metabolism". Above all, our study screens the candidate genes participated in lysine accumulation and explores the factors affected lysine biosynthesis by multi-omics analysis. These information not only paves a foundation for breeding lysine-rich quinoa sprouts but also provides valuable multi-omics resource to explore the characteristic of nutrients during quinoa germination.

Blue Light Enhances Health-Promoting Sulforaphane Accumulation in Broccoli (Brassica oleracea var. italica) Sprouts through Inhibiting Salicylic Acid Synthesis.

As a vegetable with high nutritional value, broccoli (Brassica oleracea var. italica) is rich in vitamins, antioxidants and anti-cancer compounds. Glucosinolates (GLs) are one of the important functional components widely found in cruciferous vegetables, and their hydrolysate sulforaphane (SFN) plays a key function in the anti-cancer process. Herein, we revealed that blue light significantly induced the SFN content in broccoli sprouts, and salicylic acid (SA) was involved in this process. We investigated the molecular mechanisms of SFN accumulation with blue light treatment in broccoli sprouts and the relationship between SFN and SA. The results showed that the SFN accumulation in broccoli sprouts was significantly increased under blue light illumination, and the expression of SFN synthesis-related genes was particularly up-regulated by SA under blue light. Moreover, blue light considerably decreased the SA content compared with white light, and this decrease was more suppressed by paclobutrazol (Pac, an inhibitor of SA synthesis). In addition, the transcript level of SFN synthesis-related genes and the activity of myrosinase (MYR) paralleled the trend of SFN accumulation under blue light treatment. Overall, we concluded that SA participates in the SFN accumulation in broccoli sprouts under blue light.

Transcriptome analysis reveals the molecular mechanisms of adaptation to high temperatures in Gracilaria bailinae.

Global warming causes great thermal stress to macroalgae and those species that can adapt to it are thought to be better able to cope with warmer oceans. Gracilaria bailinae, a macroalgae with high economic and ecological values, can survive through the hot summer in the South China Sea, but the molecular mechanisms underlying its adaptation to high temperatures are unclear. To address this issue, the present study analyzed the growth and transcriptome of G. bailinae after a 7-day exposure to 15°C (LT: low temperature), 25°C (MT: middle temperature), and 35°C (HT: high temperature). Growth analysis showed that the HT group had the highest relative growth rate (RGR = 2.1%) with the maximum photochemical quantum yield of PSII (F v/F m = 0.62) remaining within the normal range. Transcriptome analysis showed more differentially expressed genes (DEGs) in the comparison between MT and HT groups than in that between MT and LT, and most of these DEGs tended to be downregulated at higher temperatures. The KEGG pathway enrichment analysis showed that the DEGs were mainly enriched in the carbohydrate, energy, and lipid metabolisms. In addition, the genes involved in NADPH and ATP synthesis, which are associated with photosynthesis, the Calvin cycle, pyruvate metabolism, and the citrate cycle, were downregulated. Downregulation was also observed in genes that encode enzymes involved in fatty acid desaturation and alpha-linolenic acid metabolism. In summary, G. bailinae regulated the synthesis of NADPH and ATP, which are involved in the above-mentioned processes, to reduce unnecessary energy consumption, and limited the synthesis of enzymes in the metabolism of unsaturated fatty acids and alpha-linolenic acid to adapt to high environmental temperatures. The results of this study improve our understanding of the molecular mechanisms underlying the adaptation of G. bailinae to high temperatures.

[HRCT and MRI image of bilateral large vestibular aqueduct syndrome].

OBJECTIVE: To explore. HRCT and MRI three-dimensional fast imaging employing steady state ac-quisition(3D-FIESTA) imaging features and clinical characteristics of bilateral large vestibular aqueduct syndrome(LVAS). METHOD: The imaging and clinical features of 14 cases of bilateral LVAS identified over a 5-year periodwere retrospectively analyzed. All patients underwent HRCT and MRI 3D-FIESTA scanning of head and neck;MRI three dimensional reconstructions of internal acoustical meatus were also completed at the same time. RESULT: Audiogram showed mild to moderate hearing loss and was progressive. The cut-off values for the coronal midpointand operculum planes on the HRCT scan to diagnose an EVA were 1. 5 mm and 4. 3 mm respectively; the averagevalue was 2. 4 mm. VA expansion degree were not linked to the degree of hearing loss. MRI showed VA andlymph sac abnormalities. Concomitant image finding was cochlear hypoplasia. CONCLUSION: HRCT and MRI 3D-FI-ESTA are important examinations for accurate diagnosis of LVAS. HRCT can acquire the specific size of reamedVA. MRI and 3D reconstructions of internal acoustical meatus can noninasive show more intuitive display ofLVAS and other inner ear malformations than HRCT.