Complete chloroplast genomes of eight Artemisia species: Comparative analysis, molecular identification, and phylogenetic analysis

Artemisia L. is the largest genus in the Asteraceae, and well known for its high medicinal value. The morphological features of Artemisia species are similar, making taxonomic identification and evolutionary research difficult. We sequenced chloroplast genomes of eight Artemisia species, all of which are common adulterants of A. argyi. We used novel genetic data and compared these data to the published A. argyi chloroplast genome in to develop molecular markers for species identification and reconstructing phylogenetic relationships between Artemisia species. The eight chloroplast sequences were highly similar in gene order, content, and structure, encoding a total of 114 genes (82 protein-coding genes, 28 tRNAs, and four rRNAs). All species harboured similar repeat sequences and simple sequence repeats (SSRs), ranging from 47 to 49 and 38 to 40 repeats, respectively. In addition, we identified five hypervariable regions (rpl32-trnL, rps16-trnQ, petN-psbM, trnE-rpoB, and atpA-trnR) and ten variable coding genes (ycf1, psbG, rpl36, psaC, psaI, accD, psbT, ndhD, ndhE, and psbH), which can be used to develop chloroplast molecular markers. Finally, phylogenetic reconstructions based on six datasets produced similar topologies, revealing A. argyi is closely related to species often found as adulterants, as expected. Our research provides valuable new information on the evolution and phylogenetic relationships between Artemisia chloroplast genomes and identifies valuable molecular makers to distinguish it from closely related species.

Design, Synthesis, Antibacterial, and Antifungal Evaluation of Phenylthiazole Derivatives Containing a 1,3,4-Thiadiazole Thione Moiety

To effectively control the infection of plant pathogens, we designed and synthesized a series of phenylthiazole derivatives containing a 1,3,4-thiadiazole thione moiety and screened for their antibacterial potencies against Ralstonia solanacearum, Xanthomonas oryzae pv. oryzae, as well as their antifungal potencies against Sclerotinia sclerotiorum, Rhizoctonia solani, Magnaporthe oryzae and Colletotrichum gloeosporioides. The chemical structures of the target compounds were characterized by 1H NMR, 13C NMR and HRMS. The bioassay results revealed that all the tested compounds exhibited moderate-to-excellent antibacterial and antifungal activities against six plant pathogens. Especially, compound 5k possessed the most remarkable antibacterial activity against R. solanacearum (EC50 = 2.23 μg/mL), which was significantly superior to that of compound E1 (EC50 = 69.87 μg/mL) and the commercial agent Thiodiazole copper (EC50 = 52.01 μg/mL). Meanwhile, compound 5b displayed the most excellent antifungal activity against S. sclerotiorum (EC50 = 0.51 μg/mL), which was equivalent to that of the commercial fungicide Carbendazim (EC50 = 0.57 μg/mL). The preliminary structure-activity relationship (SAR) results suggested that introducing an electron-withdrawing group at the meta-position and ortho-position of the benzene ring could endow the final structure with remarkable antibacterial and antifungal activity, respectively. The current results indicated that these compounds were capable of serving as promising lead compounds.

Identifying the Potential of miRNAs in Houttuynia cordata-Derived Exosome-Like Nanoparticles Against Respiratory RNA Viruses

Introduction

Pathogenic respiratory RNA viruses, including influenza A virus (IAV), respiratory syncytial virus (RSV), and SARS-CoV-2, are major causes of causes of acute respiratory infection globally. Plant-derived exosome-like nanoparticles containing miRNAs have shown substantial cross-kingdom regulatory effects on both viral and human transcripts. Houttuynia cordata (H. cordata), a traditional Chinese medicine frequently used to treat respiratory diseases. However, the role of H. cordata-derived exosome-like nanoparticles (HELNs) and the miRNA they encapsulated are unclear.

Methods

HELNs were isolated from fresh underground roots (uHELNs) and above ground stems and leaves (aHELNs) using differential centrifugation. The HELNs were identified using transmission electron microscopy, nanoparticle tracking analysis, and zeta potential. Small RNA sequencing and RT-PCR were employed to determine the miRNA expression in uHELNs and aHELNs. All genomes were sourced from the NCBI database. Target prediction of viral genomes was performed using RNAhybrid, while human target prediction was conducted using both RNAhybrid and Miranda. Functional enrichment analysis was applied to the predicted human targets to explore the hub targets and their roles in antiviral effects. The accessibility of miRNA target sites was determined through the MFOLD web server, and customized dual-luciferase reporter assays were administered to validate the computational findings.

Results

A total of 12 highly enriched miRNAs were identified in both uHELNs and aHELNs. Upon prediction and verification, miR858a and miR858b were shown to target the NP gene in H1N1, while miR166a-3p targeted the ORF1ab in SARS-CoV-2. However, no valid miRNA targets were found for RSV. Regarding human transcripts, miR168a-3p, miR168b-3p, and miR8175 were found to inhibit MAPK3 expression, and novel_mir2 could suppress both AKT1 and MAPK3 expression.

Discussion

This study sheds light on the collaborative antiviral mechanism of miRNAs in HELNs across two species and explores the potential antiviral scopes of both H. cordata miRNAs and HELNs.