Comparative and phylogenetic analyses of Loranthaceae plastomes provide insights into the evolutionary trajectories of plastome degradation in hemiparasitic plants.

BACKGROUND: The lifestyle transition from autotrophy to heterotrophy often leads to extensive degradation of plastomes in parasitic plants, while the evolutionary trajectories of plastome degradation associated with parasitism in hemiparasitic plants remain poorly understood. In this study, phylogeny-oriented comparative analyses were conducted to investigate whether obligate Loranthaceae stem-parasites experienced higher degrees of plastome degradation than closely related facultative root-parasites and to explore the potential evolutionary events that triggered the 'domino effect' in plastome degradation of hemiparasitic plants. RESULTS: Through phylogeny-oriented comparative analyses, the results indicate that Loranthaceae hemiparasites have undergone varying degrees of plastome degradation as they evolved towards a heterotrophic lifestyle. Compared to closely related facultative root-parasites, all obligate stem-parasites exhibited an elevated degree plastome degradation, characterized by increased downsizing, gene loss, and pseudogenization, thereby providing empirical evidence supporting the theoretical expectation that evolution from facultative parasitism to obligate parasitism may result in a higher degree of plastome degradation in hemiparasites. Along with infra-familial divergence in Loranthaceae, several lineage-specific gene loss/pseudogenization events occurred at deep nodes, whereas further independent gene loss/pseudogenization events were observed in shallow branches. CONCLUSIONS: The findings suggest that in addition to the increasing levels of nutritional reliance on host plants, cladogenesis can be considered as another pivotal evolutionary event triggering the 'domino effect' in plastome degradation of hemiparasitic plants. These findings provide new insights into the evolutionary trajectory of plastome degradation in hemiparasitic plants.

Highly degenerate plastomes in two hemiparasitic dwarf mistletoes: Arceuthobium chinense and A. pini (Viscaceae).

MAIN CONCLUSION: The leafless and endophytic habitat may significantly relax the selection pressure on photosynthesis, and plastid transcription and translation, causing the loss/pseudogenization of several essential plastid-encoding genes in dwarf mistletoes. Dwarf mistletoes (Arceuthobium spp., Viscaceae) are the most destructive plant parasites to numerous conifer species worldwide. In this study, the plastid genomes (plastomes) of Arceuthobium chinense Lecomte and A. pini Hawksworth and Wiens were sequenced and characterized. Although dwarf mistletoes are hemiparasites capable of photosynthesis, their plastomes were highly degenerated, as indicated by the smallest plastome size, the lowest GC content, and relatively very few intact genes among the Santalales hemiparasites. Unexpectedly, several essential housekeeping genes (rpoA, rpoB, rpoC1, and rpoC2) and some core photosynthetic genes (psbZ and petL), as well as the rpl33 gene, that is indispensable for plants under stress conditions, were deleted or pseudogenized in the Arceuthobium plastomes. Our data suggest that the leafless and endophytic habit, which heavily relies on the coniferous hosts for nutrients and carbon requirement, may largely relax the selection pressure on photosynthesis, as well as plastid transcription and translation, thus resulting in the loss/pseudogenization of such essential plastid-encoding genes in dwarf mistletoes. Therefore, the higher level of plastome degradation in Arceuthobium species than other Santalales hemiparasites is likely correlated with the evolution of leafless and endophytic habit. A higher degree of plastome degradation in Arceuthobium. These findings provide new insights into the plastome degeneration associated with parasitism in Santalales and deepen our understanding of the biology of dwarf mistletoes.

The complete plastomes of two flowering epiparasites (Phacellaria glomerata and P. compressa): Gene content, organization, and plastome degradation.

A plant parasite obligately parasitizing another plant parasite is referred to as epiparasite, which is extremely rare in angiosperms, and their complete plastome sequences have not been characterized to date. In this study, the complete plastomes of two flowering epiparasites: Phacellaria compressa and P. glomerata (Amphorogynaceae, Santalales) were sequenced. The plastomes of both species are of similar size, structure, gene content, and arrangement of genes to other hemiparasites in Santalales. Their plastomes were characterized by the functional loss of plastid-encoded NAD(P)H-dehydrogenase and infA genes, which strongly coincides with the general pattern of plastome degradation observed in Santalales hemiparasites. Our study demonstrates that the relatively higher level of nutritional reliance on the host plants and the reduced vegetative bodies of P. compressa and P. glomerata do not appear to cause any unique plastome degradation compared with their closely related hemiparasites.

The Complete Plastomes of Five Hemiparasitic Plants (Osyris wightiana, Pyrularia edulis, Santalum album, Viscum liquidambaricolum, and V. ovalifolium): Comparative and Evolutionary Analyses Within Santalales.

Most species of Santalales (the sandalwood order) are hemiparasites, including both facultative and obligate hemiparasites. Despite its rich diversity, only a small fraction of the species in the sandalwood order have sequenced plastomes. The evolution of parasitism-associated plastome reduction in Santalales remains under-studied. Here, we report the complete plastomes of three facultative hemiparasites (Pyrularia edulis, Cervantesiaceae; Osyris wightiana, and Santalum album, Santalaceae), and two obligate hemiparasites (Viscum liquidambaricolum and Viscum ovalifolium, Viscaceae). Coupled with publicly available data, we investigated the dynamics of plastome degradation in Santalales hemiparasites. Our results indicate that these hemiparasites can be characterized by various degrees of plastome downsizing, structural rearrangement, and gene loss. The loss or pseudogenization of ndh genes was commonly observed in Santalales hemiparasites, which may be correlated to the lifestyle shift from photoautotroph to hemiparasitism. However, the obligate hemiparasites did not exhibit a consistently higher level of gene loss or pseudogenization compared to facultative hemiparasites, which suggests that the degree of plastome reduction is not correlated with the trophic level facultative or obligate hemiparasitism. Instead, closely related taxa tend to possess highly similar plastome size, structure, and gene content. This implies the parasitism-associated plastome degradation in Santalales may evolve in a lineage-specific manner.

Compressive myelopathy and compression fracture of aggressive vertebral hemangioma after parturition: A case report and review of literature.

RATIONALE: Compressive myelopathy and compression fracture of aggressive vertebral hemangioma after parturition is a rare condition. Vertebral body compression fracture and high serum progesterone lead to extraosseous hemangioma enlargment cause narrowing the spinal canal which contribute to compressive myelopathy relate to pregnancy. PATIENT CONCERNS: We report a case of compressive myelopathy and compression fracture of aggressive vertebral hemangioma after parturition in a 35-year-old woman. The patient complained unable to walk and experienced intense pain in the back. DIAGNOSIS: Based on the clinical features and imaging studies, the patient underwent a T4-T6 laminectomy. Histopathology consistent with vertebral hemangioma. INTERVENTIONS: The patient underwent laminectomy for decompression. After subperiosteal dissection of the paraspinal muscles and exposure of the laminae, there was no involvement of the lamina by the tumor. The epidural tumor was removed through the spaces lateral to the thecal sac. Vertebroplasty was performed through T5 pedicles bilaterally and 7 ml of polymethylmethacrylate (PMMA) cement was injected. T4-T6 pedicle screw fixation was performed for segmental fixation and fusion. OUTCOMES: Six months after resection of the tumor the patient remained asymptomatic. She reported no low back pain and had returned to her normal daily activities, with no radiographic evidence of recurrence on MRI. Physical examination revealed that superficial and deep sensation was restored to normal levels in the lower extremities. LESSONS: The occurrence of compressive myelopathy of pregnancy related vertebral hemangiomas is quite unusual. It can lead to serious neurologic deficits if not treated immediately. So, prompt diagnosis is important in planning optimal therapy and preventing morbidity for patients.

The complete plastome of Taxillus vestitus (Loranthaceae), a hemiparasitic plant.

Taxillus vestitus (Wallich) Danser (Loranthaceae) is a stem hemiparasite occurring in southwest China and Himalayas. In this study, we report the first complete plastome of this species. The plastome is 122,200 bp in size, which encodes 94 unique genes (64 protein-encoding gens, 4 ribosomal RNAs, and 26 tRNAs). Compared to the plastomes of the autotrophic relatives, the T. vestitus plastome is significantly reduced. A total of 15 protein-coding genes, and 4 tRNAs were deleted from the plastome.

Author Correction: Identifying long-term stable refugia for relict plant species in East Asia.

In the original version of this Article, an incorrect sample size was provided for the number of relict species (443 instead of 442) and the number of relict forests (423 instead of 422). These errors have been corrected in both the PDF and HTML versions of the Article.

Identifying long-term stable refugia for relict plant species in East Asia.

Today East Asia harbors many "relict" plant species whose ranges were much larger during the Paleogene-Neogene and earlier. The ecological and climatic conditions suitable for these relict species have not been identified. Here, we map the abundance and distribution patterns of relict species, showing high abundance in the humid subtropical/warm-temperate forest regions. We further use Ecological Niche Modeling to show that these patterns align with maps of climate refugia, and we predict species' chances of persistence given the future climatic changes expected for East Asia. By 2070, potentially suitable areas with high richness of relict species will decrease, although the areas as a whole will probably expand. We identify areas in southwestern China and northern Vietnam as long-term climatically stable refugia likely to preserve ancient lineages, highlighting areas that could be prioritized for conservation of such species.

Hybrid Optical Unobtrusive Blood Pressure Measurements.

Blood pressure (BP) is critical in diagnosing certain cardiovascular diseases such as hypertension. Some previous studies have proved that BP can be estimated by pulse transit time (PTT) calculated by a pair of photoplethysmography (PPG) signals at two body sites. Currently, contact PPG (cPPG) and imaging PPG (iPPG) are two feasible ways to obtain PPG signals. In this study, we proposed a hybrid system (called the ICPPG system) employing both methods that can be implemented on a wearable device, facilitating the measurement of BP in an inconspicuous way. The feasibility of the ICPPG system was validated on a dataset with 29 subjects. It has been proved that the ICPPG system is able to estimate PTT values. Moreover, the PTT measured by the new system shows a correlation on average with BP variations for most subjects, which could facilitate a new generation of BP measurement using wearable and mobile devices.

DNA barcodes for discriminating the medicinal plant Scutellaria baicalensis (Lamiaceae) and its adulterants.

Scutellaria baicalensis GEORGI (Lamiaceae) is the botanical origin of the well-known traditional Chinese medicine "Huang Qin" (Radix Scutellariae). Due to overexploitation that had induced a decline in natural sources, the dried roots of its congeners, S. amoena, S. rehderiana, and S. viscidula, have been used to adulterate it in recent years. This practice may cause a series of inconsistent therapeutic effects and quality control problems in the herbal medicine industry. Hence, we sequenced and analyzed three candidate DNA barcodes, the ribosomal RNA maturase gene (matK), the ribulose-1,4-bisphosphate carboxylase large subunit gene (rbcL), and the psbA-trnH intergenic spacer (psbA-trnH), to discriminate S. baicalensis and its adulterants. All candidate DNA barcodes had been successfully amplified from leaf samples. Comparatively, only psbA-trnH had been yielded from commercially prepared crude drug samples. Based on the sequence divergence, rbcL can assign S. baicalensis and its adulterants into the correct family and genus, whereas, either matK or psbA-trnH can accurately discriminate S. baicalensis and its adulterants. We proposed the multilocus barcodes rbcL+psbA-trnH for the species identification of S. baicalensis and its adulterants, and the unique barcode psbA-trnH for the authentication of commercial Radix Scutellariae. The DNA barcoding technique could be applied to the quality control of "Huang Qin"-based medicinal preparations and to the management of medicinal herb trade in the markets.

[Effects of doubled CO2 concentration on Erigeron breviscapus growth and its active constituent accumulation].

With medicinal plant Erigeron breviscapus as test material, its biomass and the contents and yields of scutellarin and caffeate were monitored under doubled (800 +/- 100) micromol x mol(-1) and natural (400 +/- 25) micromol x mol(-1) CO2 concentration. Comparing with those under natural CO2 concentration, the biomass of E. breviscapus under doubled CO2 concentration increased by 22%, the contents of scutellarin and caffeate increased by 23% and 26%, and the yields of these two constituents increased by 37.6% and 45.3%, respectively. Different organs had different responses in their biomass and active constituent contents to the elevated CO2 concentration. Under doubled CO2 concentration, the plant N content decreased by 47.2% and was negatively correlated with active constituent contents, being accorded well to the C/N balance hypothesis, and the biomass was positively correlated with the active constituent contents while no trade-off was observed between plant growth and secondary metabolism, suggesting that rational application of CO2 could improve the yield and quality of E. breviscapus.

[Effect of water stress on content of active constituents in Erigeron breviscaps].

OBJECTIVE: To study the effect of water stress on the content of scutellarin and caffeate in Erigeron breviscaps. METHOD: Fv/Fm, N content, as well as the content of scutellarin and caffeate under three water grads were measured. RESULT AND CONCLUSION: Fv/Fm of the plant decreased significantly in 8% and 23% water treatment, that proved drought and waterlogging occurred. Under the two conditions, the contents of N were lower but the contents of active constituents were higher than those under 15% treatment. The results support the carbon-nutrient balance hypothesis and the "stress effect hypothesis" for the formation of geo-herbs.

[Primary study on photosynthetic characteristics of Dendrobium nobile].

With LiCor-6400 Portable Photosynthesis System, carbon dioxide exchange pattern for leaves of Dendrobium nobile during 24 hours were studied in sunny day and rainy day, and the variation of CO2 exchange rate to light intensity was analysed. The results showed that in sunny day D. nobile absorbed CO2 in all day except at midday, at noon photorespiration took place. The CO2 exchange pattern was similar to Crassulacean Acid Metabolism(CAM). In rainy day CO2 uptake was in all day, at night CO2 uptake was monitored at 21:00, then CO2 released from 23:00 to dawn. Light saturation point was 1000 mumol/m2s. Over light saturation point photosynthesis, photoinhibition of photosynthesis will be induced by high-light. Exposed to high-light, the light saturation point and the CO2 uptake velocity would be decreased. With variation of environmental factors, photosynthetic pathway in D. nobile could change from CAM to C3 photosynthetic metabolism. It may be one of main reasons for D. nobile to adapt to the shade-requiring environment, the slow growth and rareness in nature.