Introduction Salvia plebeia is a medicinal plant in Lamiaceae, but its organelle genome architecture and evolutionary dynamics remain insufficiently understood, particularly for the mitochondrial genome. Methods We assembled and analyzed the mitochondrial and chloroplast genomes of S. plebeia using PacBio HiFi long-read sequencing. Genome assembly, annotation, and correction were performed using PMAT2, Minimap2, NextPolish, and GeSeq. Repetitive elements were identified using SSR, tandem repeat, and dispersed repeat analyses. Repeat-mediated recombination was validated using long-read mapping and PCR. Comparative chloroplast genomics and phylogenetic analyses were conducted using mVISTA, MUMmer4, and IQ-TREE2. RNA-editing sites were predicted using PREPACT, and codon usage bias was analyzed using CodonW. Results The mitogenome is a 444,036 bp circular molecule encoding 58 genes, while the chloroplast genome is 151,062 bp with a typical quadripartite structure. A total of 135 SSRs, 331 dispersed repeats, and 25 mitochondrial plastid DNA transfer (MTPT) regions were identified. Six repeat pairs were experimentally supported to mediate homologous recombination, indicating alternative mitochondrial conformations. RNA-editing analysis identified 587 C-to-U sites. Phylogenetic analyses placed S. plebeia within the Salvia lineage, and plastomes showed high conservation, whereas the mitogenome exhibited extensive structural rearrangements. Discussion These findings highlight a contrast between conserved chloroplast genomes and highly dynamic mitochondrial genomes in S. plebeia, driven by repeat-mediated recombination and RNA editing, providing new insights into organelle genome evolution in Lamiaceae.
Xun Gong, Keming Zhu, E. Fleming et al.· Frontiers in Plant Science· 0 citations
INTRODUCTION
To perform a two-sample Mendelian randomization (MR) analysis to explore the potential causal relationship between polymyalgia rheumatica (PMR) and hypothyroidism.
METHODS
Genome-wide association study (GWAS) data for PMR and hypothyroidism were obtained from publicly available databases. The inverse variance weighted (IVW) method was primarily used to evaluate the potential causal effect of PMR-related traits on the risk of hypothyroidism. To assess the robustness of the findings, additional methods, including the weighted median (WME), MR-Egger (ME), simple mode (SM), and weighted mode (WM), were employed. Sensitivity analyses were performed using the MR-PRESSO method and Cochran's Q test to detect potential heterogeneity and horizontal pleiotropy. Furthermore, a reverse MR analysis was performed to investigate the possibility of reverse causality.
RESULTS
IVW analysis demonstrated a significant causal relationship between PMR and hypothyroidism (OR=1.373, 95%CI:1.287-1.465, P=5.84×10⁻²²). In contrast, ME produced a non-significant result (OR=0.880, 95%CI:0.602-1.286, P=0.577). WME supported IVW findings (OR=1.373, 95%CI:1.280-1.480, P=8.97×10⁻¹⁸), as did WM (OR=1.410, 95%CI:1.243-1.599, P=0.013) and the SM (OR=1.398, 95%CI:1.240-1.575, P=0.012). Collectively, these findings provide evidence supporting a causal effect of PMR on the risk of hypothyroidism. Reverse MR analysis using the IVW method also indicated a significant causal association (OR=1.195, 95%CI:1.135-1.258, P=9.35×10-12). However, both ME regression and IVW heterogeneity tests showed evidence of heterogeneity (P=3.16×10⁻³⁸; P=4.11×10⁻³⁸). The ME analysis revealed no evidence of horizontal pleiotropy (P=0.615).
DISCUSSION
A study suggested that hypothyroidism-induced myopathic changes may mimic or exacerbate PMR symptoms, potentially leading to misdiagnosis or overtreatment with corticosteroids. Importantly, recurrence of PMR symptoms has been observed after thyroid hormone replacement, even in the presence of normalized thyroid function. These findings underscore a potential bidirectional relationship between PMR and hypothyroidism. In addition, some researchers held that HLA-B8 and DR3 may be a significant indicator to assess the association between these diseases; however, some observations suggest that it may not serve as a specific risk marker for PMR or its complications.
CONCLUSION
PMR is closely associated with the development of hypothyroidism; the risk of hypothyroidism increases as PMR progresses; on the other hand, advancing hypothyroidism may also raise the likelihood of developing PMR.
Kaige Gao, Xin Yang, Zhenyu Wang et al.· Current Rheumatology Reviews· 0 citations
