Background: Soil heavy metal pollution by chromium (Cr) and copper (Cu) is a global environmental concern. Methods: This study evaluated Cr/Cu accumulation in Paulownia fortunei tissues and analyzed its root transcriptome under Cr and Cu stress to elucidate molecular response mechanisms. Results: Findings revealed significantly higher Cr and Cu accumulation capacity in roots compared to stems and leaves. Transcriptome sequencing identified 6017 and 2265 differentially expressed genes (DEGs) under Cr and Cu stress, respectively. These DEGs were primarily involved in redox reactions, stress responses, transcriptional regulation, transmembrane transport, and metabolism. Quantitative PCR of 20 selected genes validated dynamic expression changes under stress. Weighted Gene Co-expression Network Analysis (WGCNA) identified distinct co-expression modules associated with Cr and Cu. Hub gene analysis implicated Pfo_020668 and Pfo_019190 in Cr response, while Pfo_010312 and Pfo_000197 may enhance Cu tolerance via cell wall polysaccharide synthesis regulation. Pathways related to pyruvate metabolism and proteasome were significantly enriched under Cr stress, whereas amino acid metabolism pathways were prominent under Cu stress. Conclusions: Differentially expressed transporter genes suggest potential roles in heavy metal uptake and transport. This transcriptomic analysis provides novel insights into P. fortunei’s molecular responses to Cr and Cu stress, offering a foundation for utilizing this species in soil phytoremediation efforts.

Global climate change is reshaping the habitat suitability of medicinal plants, potentially compromising their phytochemical integrity and therapeutic efficacy. Siraitia grosvenorii, an edible medicinal plant in China, has expanded its cultivation area into non-native habitats. Therefore, this study analyzed the suitable cultivation region under different periods in China based on the MaxEnt model, and 59 samples were investigated to explore the interrelationships between chemical constituents and climatic variables through multivariate statistical analysis, which will contribute to meeting the sustainable supply of high-quality S. grosvenorii. We discovered that appropriate habitats cover an area of 58.76 × 10⁴ km², mainly in the southern parts of China. Under future climate conditions, suitable habitats decrease and shift to the northeast along the current habitats. The precipitation levels of the driest month, precipitation seasonality, and temperature seasonality were crucial for its distribution. Furthermore, 11 elements were identified to distinguish samples from different suitable areas through orthogonal partial least squares discriminant analysis. Correlation analysis revealed a strong association between chemical constituents and various climatic factors. This study offers valuable insights into potential S. grosvenorii cultivation areas in China and provides reference indicators for quality evaluation.

Three viruses, Telosma mosaic virus (TeMV), East Asian passiflora virus (EAPV), and Cucumber mosaic virus (CMV), are widespread in Chinese passion fruit growing regions. Co-infection by these three viruses was confirmed in symptomatic field samples collected from Guilin. To evaluate the effectiveness of shoot tip culture alone for virus elimination, in vitro organogenesis was examined, and both direct (DOR) and indirect (IOR) regeneration pathways were observed. In the DOR pathway, organogenic buds and nodules were induced at a rate of 40.83%, and 14.86% of explants produced adventitious buds longer than 1 cm. In the IOR pathway, callus was induced at a rate of 26.67%, and callus-derived meristemoids yielded a bud induction rate of 7.46%. Semi-quantitative PCR analysis showed that only a few virus-free plantlets were obtained, and no regenerated plantlets were found to simultaneously eliminate two or three viruses. No significant difference in median virus elimination efficiency was detected between the DOR and IOR pathways (TeMV: 0% vs. 16.67%; EAPV: 16.67% vs. 0%; CMV: 33.33% vs. 16.67%). SSR analysis confirmed genetic stability in the DOR pathway, whereas a polymorphism rate of 27.27% was observed in the IOR pathway. These findings indicate that the DOR pathway maintains genetic stability while achieving elimination of certain viruses in a small number of co-infected plantlets, providing a basis for subsequent secondary virus elimination and combined treatments.

Three viruses, Telosma mosaic virus (TeMV), East Asian passiflora virus (EAPV), and Cucumber mosaic virus (CMV), were found to be widespread in Chinese purple passion fruit (Passiflora edulis Sims) growing regions, with co-infection by these three viruses confirmed in symptomatic field samples collected from Guilin. To evaluate the effectiveness of single shoot tip culture for virus elimination, in vitro organogenesis was examined, and both direct (DOR) and indirect (IOR) organogenesis pathways were observed. In the DOR pathway, organogenic buds and nodules were induced at a rate of 40.83%, and adventitious buds longer than 1 cm were produced by 14.86% of explants. In the IOR pathway, callus was induced at a rate of 26.67%, and a bud induction rate of 7.46% was obtained from callus-derived meristemoids. Semi-quantitative reverse transcription polymerase chain reaction (semi-qPCR) analysis revealed that viral RNA was undetectable in only a few regenerated plantlets, and none of the plantlets tested negative for two or three viruses simultaneously. The proportion of plantlets with detectable virus loss was comparable between the DOR and IOR pathways (TeMV: 5.56% vs. 11.11%; EAPV: 16.67% vs. 5.56%; CMV: 27.78% vs. 16.67%). All tested Simple Sequence Repeat (SSR) loci were monomorphic in the DOR pathway, whereas a polymorphism rate of 27.27% was observed in the IOR pathway. These findings indicate that the DOR pathway yielded only monomorphic bands at the assessed SSR loci while enabling the production of a small number of plantlets with viral RNA levels below the semi-qPCR detection limit, providing a basis for the subsequent application of more sensitive detection methods and combined treatment strategies.