Genome-Wide Identification and Characterization of R2R3-MYB Provide Insight into Anthocyanin Biosynthesis Regulation Mechanism of Ananas comosus var. bracteatus.

The R2R3-MYB proteins comprise the largest class of MYB transcription factors, which play an essential role in regulating anthocyanin synthesis in various plant species. Ananas comosus var. bracteatus is an important colorful anthocyanins-rich garden plant. The spatio-temporal accumulation of anthocyanins in chimeric leaves, bracts, flowers, and peels makes it an important plant with a long ornamental period and highly improves its commercial value. We conducted a comprehensive bioinformatic analysis of the R2R3-MYB gene family based on genome data from A. comosus var. bracteatus. Phylogenetic analysis, gene structure and motif analysis, gene duplication, collinearity, and promoter analysis were used to analyze the characteristics of this gene family. In this work, a total of 99 R2R3-MYB genes were identified and classified into 33 subfamilies according to phylogenetic analysis, and most of them were localized in the nucleus. We found these genes were mapped to 25 chromosomes. Gene structure and protein motifs were conserved among AbR2R3-MYB genes, especially within the same subfamily. Collinearity analysis revealed four pairs of tandem duplicated genes and 32 segmental duplicates in AbR2R3-MYB genes, indicating that segmental duplication contributed to the amplification of the AbR2R3-MYB gene family. A total of 273 ABRE responsiveness, 66 TCA elements, 97 CGTCA motifs, and TGACG motifs were the main cis elements in the promoter region under response to ABA, SA, and MEJA. These results revealed the potential function of AbR2R3-MYB genes in response to hormone stress. Ten R2R3-MYBs were found to have high homology to MYB proteins reported to be involved in anthocyanin biosynthesis from other plants. RT-qPCR results revealed the 10 AbR2R3-MYB genes showed tissue-specific expression patterns, six of them expressed the highest in the flower, two genes in the bract, and two genes in the leaf. These results suggested that these genes may be the candidates that regulate anthocyanin biosynthesis of A. comosus var. bracteatus in the flower, leaf, and bract, respectively. In addition, the expressions of these 10 AbR2R3-MYB genes were differentially induced by ABA, MEJA, and SA, implying that these genes may play crucial roles in hormone-induced anthocyanin biosynthesis. Our study provided a comprehensive and systematic analysis of AbR2R3-MYB genes and identified the AbR2R3-MYB genes regulating the spatial-temporal anthocyanin biosynthesis in A. comosus var. bracteatus, which would be valuable for further study on the anthocyanin regulation mechanism of A. comosus var. bracteatus.

Carbonation Curing on Magnetically Separated Steel Slag for the Preparation of Artificial Reefs.

Magnetic separation is an effective method to recover iron from steel slag. However, the ultra-fine tailings generated from steel slag become a new issue for utilization. The dry separation processes generates steel slag powder, which has hydration activity and can be used as cement filler. However, wet separation processes produce steel slag mud, which has lost its hydration activity and is no longer suitable to be used as a cement filler. This study investigates the potential of magnetically separated steel slag for carbonation curing and the potential use of the carbonated products as an artificial reef. Steel slag powder and steel slag mud were moulded, carbonation-cured and seawater-cured. Various testing methods were used to characterize the macro and micro properties of the materials. The results obtained show that carbonation and hydration collaborated during the carbonation curing process of steel slag powder, while only carbonation happened during the carbonation curing process of steel slag mud. The seawater-curing process of carbonated steel slag powder compact had three stages: C-S-H gel formation, C-S-H gel decomposition and equilibrium, which were in correspondence to the compressive strength of compact increasing, decreasing and unchanged. However, the seawater-curing process of carbonated steel slag mud compact suffered three stages: C-S-H gel decomposition, calcite transfer to vaterite and equilibrium, which made the compressive strength of compact decreased, increased and unchanged. Carbonated steel slags tailings after magnetic separation underwent their lowest compressive strength when seawater-cured for 7 days. The amount of CaO in the carbonation active minerals in the steel slag determined the carbonation consolidation ability of steel slag and durability of the carbonated steel slag compacts. This paper provides a reference for preparation of artificial reefs and marine coagulation materials by the carbonation curing of steel slag.

The highly continuous reference genome of a leaf-chimeric red pineapple (Ananas comosus var. bracteatus f. tricolor) provides insights into elaboration of leaf color.

Ananas comosus var. bracteatus f. tricolor (GL1) is a red pineapple accession whose mostly green leaves with chimeric white leaf margins turn red in spring and autumn and during flowering. It is an important ornamental plant and ideal plant research model for anthocyanin metabolism, chimeric leaf development, and photosynthesis. Here, we generated a highly contiguous chromosome-scale genome assembly for GL1 and compared it with other 3 published pineapple assemblies (var. comosus accessions MD2 and F153, and var. bracteatus accession CB5). The GL1 assembly has a total size of ∼461 Mb, with a contig N50 of ∼2.97 Mb and Benchmarking Universal Single-Copy Ortholog score of 97.3%. More than 99% of the contigs are anchored to 25 pseudochromosomes. Compared with the other 3 published pineapple assemblies, the GL1 assembly was confirmed to be more continuous. Our evolutionary analysis showed that the Bromeliaceae and Poaceae diverged from their nearest common ancestor ∼82.36 million years ago (MYA). Population structure analysis showed that while GL1 has not undergone admixture, bracteatus accession CB5 has resulted from admixture of 3 species of Ananas. Through classification of orthogroups, analysis of genes under positive selection, and analysis of presence/absence variants, we identified a series of genes related to anthocyanin metabolism and development of chimeric leaves. The structure and evolution of these genes were compared among the published pineapple assemblies with reveal candidate genes for these traits. The GL1 genome assembly and its comparisons with other 3 pineapple genome assemblies provide a valuable resource for the genetic improvement of pineapple and serve as a model for understanding the genomic basis of important traits in different pineapple varieties and other pan-cereal crops.

Silver Nanoparticle's Toxicological Effects and Phytoremediation.

The advancement in nanotechnology has brought numerous benefits for humans in diverse areas including industry, medicine, and agriculture. The demand in the application of nanomaterials can result in the release of these anthropogenic materials into soil and water that can potentially harm the environment by affecting water and soil properties (e.g., soil texture, pH, organic matter, and water content), plants, animals, and subsequently human health. The properties of nanoparticles including their size, surface area, and reactivity affect their fate in the environment and can potentially result in their toxicological effects in the ecosystem and on living organisms. There is extensive research on the application of nano-based materials and the consequences of their release into the environment. However, there is little information about environmentally friendly approaches for removing nanomaterials from the environment. This article provides insight into the application of silver nanoparticles (AgNPs), as one of the most commonly used nanomaterials, their toxicological effects, their impacts on plants and microorganisms, and briefly reviews the possibility of remediation of these metabolites using phytotechnology approaches. This article provides invaluable information to better understand the fate of nanomaterials in the environment and strategies in removing them from the environment.

Comparative transcriptomic and proteomic analyses of the green and white parts of chimeric leaves in Ananas comosus var. bracteatus.

BACKGROUND: Ananas comosus var. bracteatus has high ornamental value due to its chimeric leaves. However, the chimeric trait is very unstable in red pineapple plants, and transcriptional variation between the two types of cells (white/green cells) and the molecular mechanism responsible for their albino phenotype remain poorly understood. METHODS: Comparative transcriptomic and proteomic analyses of the white parts (Whs) and green parts (Grs) of chimeric leaves were performed. RESULTS: In total, 1,685 differentially expressed genes (DEGs) (712 upregulated and 973 downregulated) and 1,813 differentially abundant proteins (DAPs) (1,018 with low abundance and 795 with high abundance) were identified. Based on Gene Ontology (Go) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses, the DEGs were mostly involved in carbon fixation in photosynthetic organisms, porphyrin and chlorophyll metabolism and oxidative phosphorylation, while proteomic analysis revealed that DAPs were mostly related to ribosomes, photosynthesis, photosynthesis antennas, and porphyrin and chlorophyll metabolism. Combined analysis showed increased mRNA levels but low abundance of nine proteins level in Whs /Grs related to photosynthetic pigment and photosynthesis. Transcriptional changes, posttranscriptional regulation and translational alterations of key enzymes involved in chlorophyll biosynthesis and photosynthesis may play important roles in the albino parts of chimeric leaves.

High-throughput sequencing analysis revealed the regulation patterns of small RNAs on the development of A. comosus var. bracteatus leaves.

Studies of the molecular mechanisms involved in the formation of the albino leaf cells are important for understanding the development of chimera leaves in Ananas comosus var. bracteatus. In this study, we identified a total of 163 novel miRNAs involved in the development of complete white (CWh) and complete green (CGr) leaves using high-throughput sequencing method. The potential miRNA target genes were predicted and annotated using the NR, Swiss-Prot, GO, COG, KEGG, KOG and Pfam databases. The main biological processes regulated by miRNAs were revealed. The miRNAs which potentially play important roles in the development of the leaves and the albino of the CWh leaf cells were selected and their expression patterns were analyzed. The expression levels of nine miRNAs and their potential target genes were studied using qRT-PCR. These results will help to elucidate the functional and regulatory roles of miRNAs in the formation of the albino cells and the development of the leaves of A. comosus var. bracteatus. These data may also be helpful as a resource for studies of small RNA in other leaf color chimeric plant species.

Inter-simple sequence repeat data reveals high genetic diversity in wild populations of the narrowly distributed endemic Lilium regale in the Minjiang River Valley of China.

Lilium regale E.H. Wilson is endemic to a narrow geographic area in the Minjiang River valley in southwestern China, and is considered an important germplasm for breeding commercially valuable lily varieties, due to its vigorous growth, resistance to diseases and tolerance for low moisture. We analyzed the genetic diversity of eight populations of L. regale sampled across the entire natural distribution range of the species using Inter-Simple Sequence Repeat markers. The genetic diversity (expected heterozygosity= 0.3356) was higher than those reported for other narrowly distributed endemic plants. The levels of inbreeding (Fst = 0.1897) were low, and most of the genetic variability was found to be within (80.91%) than amongpopulations (19.09%). An indirect estimate of historical levels of gene flow (Nm =1.0678) indicated high levels of gene flow among populations. The eight analyzed populations clustered into three genetically distinct groups. Based on these results, we recommend conservation of large populations representing these three genetically distinct groups.

Icariin from Epimedium brevicornum attenuates chronic mild stress-induced behavioral and neuroendocrinological alterations in male Wistar rats.

Chronic mild stress (CMS) is suggested to produce abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis and hypothalamus-pituitary-thyroid (HPT) axis. Therefore, compound that attenuates the neuroendocrinological alterations may have potential as antidepressant. The behavioral and neuroendocrinological effects of icariin, a major constituent of flavonoids isolated from Epimedium brevicornum, were investigated in the CMS model of depression in male Wistar rats. CMS procedure caused an anhedonic state in rats resulted in increased corticotropin-releasing factor (CRF) concentrations in dissected brain regions and serum, decreased total triiodothyronine (tT3) in serum with no significant changes in serum adrenocorticotrophic hormone (ACTH) and thyroxine (tT4). Administration of icariin reversed CMS-induced sucrose intake reduction and CRF elevation. These results suggested that icariin possessed potent antidepressant-like activities which were at least in part mediated by improving the abnormalities in the HPA axis functions. However, we did not find a clear correlation between the HPT axis and icariin treatment in the CMS-treated rats.