Research on Phenolic Content and Its Antioxidant Activities in Fermented Rosa rugosa 'Dianhong' Petals with Brown Sugar.

Fermented Rosa rugosa 'Dianhong' petals with brown sugar, a biologically active food popularized in Dali Prefecture, Northwest Yunnan, China, are rich in bioactive compounds, especially polyphenols, exhibiting strong antioxidant activity. This study evaluated their antioxidant activities, total phenolic contents, and concentrations of polyphenols at different fermentation conditions using different assays: DPPH free-radical scavenging activity, Trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), Folin-Ciocalteu assays, and HPLC-MS/MS and HPLC-DAD methods. The results indicated that fermentation significantly increased (p < 0.05) the antioxidant activity and polyphenol concentration of R. rugosa 'Dianhong'. Furthermore, Saccharomyces rouxii TFR-1 fermentation achieved optimal bioactivity earlier than natural fermentation. Overall, we found that the use of Saccharomyces rouxii (TFR-1) is a more effective strategy for the production of polyphenol-rich fermented R. rugosa 'Dianhong' petals with brown sugar compared to natural fermentation.

Changes in the antioxidant and anti-inflammatory activities of Rosa rugosa 'Mohong' during fermentation.

Fermented rose petals are a traditional delicacy of the Dali Bai community in Yunnan, China. Fermentation enhances the quality and nutritional value of roses, as well as their efficacy, by increasing the levels of phenolic compounds. This study aimed to investigate the significant variations in four active compounds throughout the traditional fermentation process. Four compounds in Rosa rugosa 'Mohong' were examined, and significant variations among polyphenols and antioxidant and anti-inflammatory activities were observed. These variations were studied during fermentation by Saccharomyces rouxii at varying temperatures and durations. Moreover, the results showed that gallic acid and syringic acid content significantly increased (P < 0.05) with a rise in temperature from 20°C-35 °C during fermentation. Simultaneously, rutin and quercetin levels significantly decreased (P < 0.05) at all four temperatures throughout the five periods. The antioxidant and anti-inflammatory activities of fermented R. rugosa 'Mohong' methanol extracts were dose-dependent. Our results provide valuable insights into optimizing the processing scale and quality control of fermented rose products.

Identification of miRNAs and Their Response to Cold Stress in Astragalus Membranaceus.

Astragalus membranaceus is an important medicinal plant widely cultivated in East Asia. MicroRNAs (miRNAs) are endogenous regulatory molecules that play essential roles in plant growth, development, and the response to environmental stresses. Cold is one of the key environmental factors affecting the yield and quality of A. membranaceus, and miRNAs may mediate the gene regulation network under cold stress in A. membranaceus. To identify miRNAs and reveal their functions in cold stress response in A. membranaceus, small RNA sequencing was conducted followed by bioinformatics analysis, and quantitative real time PCR (qRT-PCR) analysis was performed to profile the expression of miRNAs under cold stress. A total of 168 conserved miRNAs belonging to 34 families and 14 putative non-conserved miRNAs were identified. Many miRNA targets were predicted and these targets were involved in diversified regulatory and metabolic pathways. By using qRT-PCR, 27 miRNAs were found to be responsive to cold stress, including 4 cold stress-induced and 17 cold-repressed conserved miRNAs, and 6 cold-induced non-conserved miRNAs. These cold-responsive miRNAs probably mediate the response to cold stress by regulating development, hormone signaling, defense, redox homeostasis, and secondary metabolism in A. membranaceus. These cold-corresponsive miRNAs may be used as the candidate genes in further molecular breeding for improving cold tolerance of A. membranaceus.

Characterization of the complete chloroplast genome of Nitraria tangutorum, a desert shrub.

The chloroplast genome sequence of Nitraria tangutorum, a desert shrub, was sequenced using high-throughput sequencing technology and analysed phylogenetically in the present study. The chloroplast genome is 159,414 bp in length, including a large single copy region of 87,924 bp and small single copy region of 18,318 bp, and a pair of inverted repeat regions of 26,586 bp. The chloroplast genome contains 110 unique genes, including 77 protein-coding genes, four ribosomal RNA genes, and 29 tRNA genes. Most of these genes are present as a single copy and in two or more copies 19 genes occurred. Seventeen genes have one intron, and clpP and ycf3 genes contain two introns. A total of 81 simple sequence repeats (SSRs) were identified, most of them were found to be mononucleotide repeats composed of A/T. In addition to SSRs, 66 repeats were identified, including 41 tandem repeats, 10 palindromic repeats, and 15 forward repeats. The phylogenetic analysis based on 54 protein-coding genes demonstrated a close relationship between N. tangutorum and other plant species in Sapindales. The complete chloroplast genome sequence of N. tangutorum will provide important data for further study of taxonomy and systematics of the genus Nitraria.

Long-read sequencing and de novo genome assembly of Ammopiptanthus nanus, a desert shrub.

Background: Ammopiptanthus nanus is a rare broad-leaved shrub that is found in the desert and arid regions of Central Asia. This plant species exhibits extremely high tolerance to drought and freezing and has been used in abiotic tolerance research in plants. As a relic of the tertiary period, A. nanus is of great significance to plant biogeographic research in the ancient Mediterranean region. Here, we report a draft genome assembly using the Pacific Biosciences (PacBio) platform and gene annotation for A. nanus. Findings: A total of 64.72 Gb of raw PacBio sequel reads were generated from four 20-kb libraries. After filtering, 64.53 Gb of clean reads were obtained, giving 72.59× coverage depth. Assembly using Canu gave an assembly length of 823.74 Mb, with a contig N50 of 2.76 Mb. The final size of the assembled A. nanus genome was close to the 889 Mb estimated by k-mer analysis. The gene annotation completeness was evaluated using Benchmarking Universal Single-Copy Orthologs; 1,327 of the 1,440 conserved genes (92.15%) could be found in the A. nanus assembly. Genome annotation revealed that 74.08% of the A. nanus genome is composed of repetitive elements and 53.44% is composed of long terminal repeat elements. We predicted 37,188 protein-coding genes, of which 96.53% were functionally annotated. Conclusions: The genomic sequences of A. nanus could be a valuable source for comparative genomic analysis in the legume family and will be useful for understanding the phylogenetic relationships of the Thermopsideae and the evolutionary response of plant species to the Qinghai Tibetan Plateau uplift.