Survival in nunatak and peripheral glacial refugia of three alpine plant species is partly predicted by altitudinal segregation.

Mountain biota survived the Quaternary cold stages most probably in peripheral refugia and/or ice-free peaks within ice-sheets (nunataks). While survival in peripheral refugia has been broadly demonstrated, evidence for nunatak refugia is still scarce. We generated RADseq data from three mountain plant species occurring at different elevations in the southeastern European Alps to investigate the role of different glacial refugia during the Last Glacial Maximum (LGM). We tested the following hypotheses. (i) The deep Piave Valley forms the deepest genetic split in the species distributed across it, delimiting two peripheral refugia. (ii) The montane to alpine species Campanula morettiana and Primula tyrolensis survived the LGM in peripheral refugia, while high-alpine to subnival Saxifraga facchinii likely survived in several nunatak refugia. (iii) The lower elevation species suffered a strong population decline during the LGM. By contrast, the higher elevation species shows long-term stability of population sizes due to survival on permanently ice-free peaks and small population sizes at present. We found peripheral refugia on both sides of the Piave Valley, which acted as a major genetic barrier. Demographic modelling confirmed nunatak survival not only for S. facchinii but also for montane to alpine C. morettiana. Altitudinal segregation influenced the species' demographic fluctuations, with the lower elevation species showing a significant population increase at the end of the LGM, and the higher elevation species either showing decrease towards the present or stable population sizes with a short bottleneck. Our results highlight the role of nunatak survival and species ecology in the demographic history of mountain species.

High-intensity light promotes adaptive divergence of photosynthetic traits between sun-exposed and shaded populations in Saxifraga fortunei.

PREMISE: Light is essential for plants, and local populations exhibit adaptive photosynthetic traits depending on their habitats. Although plastic responses in morphological and/or physiological characteristics to different light intensities are well known, adaptive divergence with genetic variation remains to be explored. This study focused on Saxifraga fortunei (Saxifragaceae) growing in sun-exposed and shaded habitats. METHODS: We measured the leaf anatomical structure and photosynthetic rate of plants grown in their natural habitats and in a common greenhouse (high- and low-intensity light experimental sites). To assess differences in ecophysiological tolerance to high-intensity light between the sun and shade types, we evaluated the level of photoinhibition of photosystem II and the leaf mortality rate under high-intensity light conditions. In addition, population genetic analysis was conducted to investigate phylogenetic origins. RESULTS: Clear phenotypic differences were found between the sun and shade types despite their recent phylogenetic origin. The leaf anatomical structure and photosynthetic rate showed plastic changes in response to growing conditions. Moreover, the sun type had a well-developed palisade parenchyma and a higher photosynthetic rate, which were genetically fixed, and a lower level of photoinhibition under high-intensity light. CONCLUSIONS: Our findings demonstrate that light intensity is a selective pressure that can rapidly promote phenotypic divergence between the sun and shade types. While phenotypic changes in multiple photosynthetic traits were plastic, genetic divergence in specific traits related to adaptation to high-intensity light would be fundamental for ecotypic divergence to different light regimes.

Rapid Virucidal Activity of Japanese Saxifraga Species-Derived Condensed Tannins against SARS-CoV-2, Influenza A Virus, and Human Norovirus Surrogate Viruses.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), influenza A virus (IAV), and norovirus are global threats to human health. The application of effective virucidal agents, which contribute to the inactivation of viruses on hands and environmental surfaces, is important to facilitate robust virus infection control measures. Naturally derived virucidal disinfectants have attracted attention owing to their safety and eco-friendly properties. In this study, we showed that multiple Japanese Saxifraga species-derived fractions demonstrated rapid, potent virucidal activity against the SARS-CoV-2 ancestral strain and multiple variant strains, IAV, and two human norovirus surrogates: feline calicivirus (FCV) and murine norovirus (MNV). Condensed tannins were identified as active chemical constituents that play a central role in the virucidal activities of these fractions. At a concentration of 25 µg/mL, the purified condensed tannin fraction Sst-2R induced significant reductions in the viral titers of the SARS-CoV-2 ancestral strain, IAV, and FCV (reductions of ≥3.13, ≥3.00, and 2.50 log10 50% tissue culture infective doses [TCID50]/mL, respectively) within 10 s of reaction time. Furthermore, at a concentration of 100 µg/mL, Sst-2R induced a reduction of 1.75 log10 TCID50/mL in the viral titers of MNV within 1 min. Western blotting and transmission electron microscopy analyses revealed that Sst-2R produced structural abnormalities in viral structural proteins and envelopes, resulting in the destruction of viral particles. Furthermore, Saxifraga species-derived fraction-containing cream showed virucidal activity against multiple viruses within 10 min. Our findings indicate that Saxifraga species-derived fractions containing condensed tannins can be used as disinfectants against multiple viruses on hands and environmental surfaces. IMPORTANCE SARS-CoV-2, IAV, and norovirus are highly contagious pathogens. The use of naturally derived components as novel virucidal/antiviral agents is currently attracting attention. We showed that fractions from extracts of Saxifraga species, in the form of a solution as well as a cream, exerted potent, rapid virucidal activities against SARS-CoV-2, IAV, and surrogates of human norovirus. Condensed tannins were found to play a central role in this activity. The in vitro cytotoxicity of the purified condensed tannin fraction at a concentration that exhibited some extent of virucidal activity was lower than that of 70% ethanol or 2,000 ppm sodium hypochlorite solution, which are popular virucidal disinfectants. Our study suggests that Saxifraga species-derived fractions containing condensed tannins can be used on hands and environmental surfaces as safe virucidal agents against multiple viruses.

Homoploid hybrids are common but evolutionary dead ends, whereas polyploidy is not linked to hybridization in a group of Pyrenean saxifrages.

Hybridization and polyploidy are major forces in plant evolution. Homoploid hybridization can generate new species via hybrid speciation, or modify extant evolutionary lineages through introgression. Polyploidy enables instantaneous reproductive isolation from the parental lineage(s) and is often coupled with evolutionary innovations, especially when linked to hybridization. While allopolyploidy is a well-known and common mechanism of plant speciation, the evolutionary role of autopolyploidy might have been underestimated. Here, we studied the saxifrages of Saxifraga subsection Saxifraga in the Pyrenees, which easily hybridise and include polyploid populations of uncertain origin, as a model to unravel evolutionary consequences and origin of hybridization and polyploidy. Additionally, we investigate the phylogenetic relationship between the two subspecies of the endemic S. pubescens to ascertain whether they should rather be treated as different species. For these purposes, we combined ploidy-informed restriction associated DNA analyses, plastid DNA sequences and morphological data on a comprehensive population sample of seven species. Our results unravel multiple homoploid hybridization events at the diploid level between different species pairs, but with limited evolutionary impact. The ploidy-informed analyses reveal that all tetraploid populations detected in the present study belong to the widespread alpine species S. moschata. Although of autopolyploid origin, they are to some extent morphologically differentiated and underwent a different evolutionary pathway than their diploid parent. However, the high plastid DNA diversity and the internal structure within eastern and western population groups suggest multiple origins of the polyploids. Finally, our phylogenetic analyses show that S. pubescens and S. iratiana are clearly not sister lineages, and should consequently be considered as independent species.

Exploring the hypolipidemic effects of bergenin from Saxifraga melanocentra Franch: mechanistic insights and potential for hyperlipidemia treatment.

OBJECTIVE: The goal of this study was to explore the hypolipidemic effects of bergenin extracted from Saxifraga melanocentra Franch (S. melanocentra), which is a frequently utilized Tibetan medicinal plant known for its diverse bioactivities. Establishing a quality control system for black stem saxifrage is crucial to ensure the rational utilization of its medicinal resources. METHODS: A one-step polyamide medium-pressure liquid chromatography technique was applied to isolate and prepare bergenin from a methanol extract of S. melanocentra. A zebrafish model of hyperlipidemia was used to investigate the potential hypolipidemic effects of bergenin. RESULTS: The results revealed that bergenin exhibited substantial hypo efficacy in vivo. Specifically, bergenin significantly reduced the levels of triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol (LDL-c) while simultaneously increasing high-density lipoprotein cholesterol (HDL-c) levels. At the molecular level, bergenin exerted its effects by inhibiting the expression of FASN, SREBF1, HMGCRα, RORα, LDLRα, IL-1ß, and TNF while promoting the expression of IL-4 at the transcriptional level. Molecular docking analysis further demonstrated the strong binding affinity of bergenin to proteins such as FASN, SREBF1, HMGCRα, RORα, LDLRα, IL-4, IL-1ß, and TNF. CONCLUSIONS: Findings indicate that bergenin modulates lipid metabolism by regulating lipid and cholesterol synthesis as well as inflammatory responses through signaling pathways associated with FASN, SREBF1, and RORα. These results position bergenin as a potential candidate for the treatment of hyperlipidemia.

Seven New Phenylhexanoids with Antioxidant Activity from Saxifraga umbellulata var. pectinata.

Seven new phenylhexanoids, (S)-(+)-3,4-dihydroxy-11-methoxyphenylhex-9-one (1), (E) 3,4-dihydroxy-phenylhex-10-en-9-one (2), (E)-4-hydroxyphenylhex-10-en-9-one (3), (R)-(-)-3,4,11-trihydroxyphenylhex-9-one 11-O-ß-d-glucopyranoside (4), (R)-(-)-4,11-dihydroxyphenylhex-9-one 11-O-ß-d-glucopyranoside (5), phenylhex-4,9,11-triol 11-O-ß-d-glucopyranoside (6), and 9-O-acetyl-phenylhex-4,9,11-triol 11-O-ß-d-glucopyranoside (7), were isolated and identified from Tibetan medicine Saxifraga umbellulata var. pectinate. The antioxidant activities of these compounds were evaluated using the DPPH and ABTS radical scavenging experiments. In the ABTS experiment, compounds 1 (IC50 13.99 ± 2.53 µM) and 2 (IC50 13.11 ± 0.94 µM) exhibited significantly better antioxidant activity than L-ascorbic acid (IC50 23.51 ± 0.44 µM).

Targeted isolation of 1,1-diphenyl-2-picrylhydrazyl inhibitors from Saxifraga atrata and their antioxidant activities.

Saxifraga atrata is an important traditional Tibetan medicine used to treat cough and pneumonia, and has tremendous medicinal potential. In this study, we devised a technique to separate 1,1-diphenyl-2-picrylhydrazyl inhibitors from a methanol extract of S. atrata. The material was first processed using MCI GEL CHP20P medium-pressure liquid chromatography, yielding 1.1 g of the target fraction Fr2. Subsequently, online hydrophilic interaction liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay was used to identify prospective 1,1-diphenyl-2-picrylhydrazyl inhibitors, and two 1,1-diphenyl-2-picrylhydrazyl inhibitor fractions (Fr24 and Fr25) were identified from Fr2. Then, medium-pressure preparation was continued using an XIon column to separate two 1,1-diphenyl-2-picrylhydrazyl inhibitor fractions (Fr24 and Fr25). The target compound was concentrated in fractions Fr24 and Fr25 using reverse-phase liquid chromatography during further separation procedures. Finally, the purity, structure, and 1,1-diphenyl-2-picrylhydrazyl inhibitory activity of the isolated 1,1-diphenyl-2-picrylhydrazyl inhibitors were determined. Two 1,1-diphenyl-2-picrylhydrazyl inhibitors (adenosine with the half maximal inhibitory concentration of 66.87 ± 14.33 µM and (-)-4-O-(E)-caffeoyl-l-threonic acid with the half maximal inhibitory concentration of 59.06 ± 5.02 µM) were isolated with purities exceeding 95%. The results showed that this technology is effective in the targeted separation of antioxidants from natural products.

Extreme diversification of floral volatiles within and among species of Lithophragma (Saxifragaceae).

A major challenge in evolutionary biology is to understand how complex traits of multiple functions have diversified and codiversified across interacting lineages and geographic ranges. We evaluate intra- and interspecific variation in floral scent, which is a complex trait of documented importance for mutualistic and antagonistic interactions between plants, pollinators, and herbivores. We performed a large-scale, phylogenetically structured study of an entire plant genus (Lithophragma, Saxifragaceae), of which several species are coevolving with specialized pollinating floral parasites of the moth genus Greya (Prodoxidae). We sampled 94 Lithophragma populations distributed across all 12 recognized Lithophragma species and subspecies, and four populations of related saxifragaceous species. Our results reveal an unusually high diversity of floral volatiles among populations, species, and clades within the genus. Moreover, we found unexpectedly major changes at each of these levels in the biosynthetic pathways used by local populations in their floral scents. Finally, we detected significant, but variable, genus- and species-level patterns of ecological convergence in the floral scent signal, including an impact of the presence and absence of two pollinating Greya moth species. We propose that one potential key to understanding floral scent variation in this hypervariable genus is its geographically diverse interactions with the obligate specialized Greya moths and, in some species and sites, more generalized copollinators.

Two Olean-27-carboxylic Acid-Type Triterpenoids as Chemical Markers Isolated from Saxifraga umbellulata.

Two olean-27-carboxylic acid-type triterpenoids (1 and 2) were isolated from Saxifraga umbellulata (Saxifragaceae), representing the first case in the chemical discoveries of genus Saxifraga. Compound 1 was determined to be a new compound named 'Saxifragic acid' based on the comprehensive spectroscopic and X-ray crystallographic analyses. Compound 2 (deacetylated saxifragic acid) is a known compound reported before, but its absolute configuration through X-ray crystallographic analyses was first described here. In addition, their cytotoxicity against five digestive human cancer cell lines (BGC-823, GBC-SD, CCC-9810, HT-29, and HepG2) and hepatoprotective activity against CCl4 -induced L-o2 cell injury in vitro were evaluated. Interestingly, UPLC-QTOFMS analysis showed that these two compounds could be used as chemical markers to discriminate between S. umbellulata and S. tangutica, both of which are used for the treatment of hepatobiliary diseases in traditional Tibetan medicine.

Clinical Potential of Himalayan Herb Bergenia ligulata: An Evidence-Based Study.

Herbal products have been used in traditional systems of medicine and by ethnic healers for ages to treat various diseases. Currently, it is estimated that about 80% of people worldwide use herbal traditional medicines against various ailments, partly due to easy accessibility and low cost, and the lower side effects they pose. Bergenia ligulata, a herb ranging from the Himalayas to the foothills, including the north-eastern states of India, has traditionally been used as a remedy against various diseases, most prominently kidney stones. The medicinal properties of B. ligulata have been attributed to bergenin, its most potent bioactive component. Apart from bergenin, the other compounds available in B. ligulata are arbutin, gallic acid, protocatechuic acid, chlorogenic acid, syringic acid, catechin, ferulic acid, afzelechin, paashaanolactone, caryophyllene, 1,8-cineole, ß-eudesmol, stigmasterol, ß-sitosterol, parasorbic acid, 3-methyl-2-buten-1-ol, phytol, terpinen-4-ol, tannic acid, isovalaric acid, avicularin, quercetin, reynoutrin, and sitoinoside I. This review summarizes various medicinal properties of the herb, along with providing deep insight into its bioactive molecules and their potential roles in the amelioration of human ailments. Additionally, the possible mechanism(s) of action of the herb's anti-urolithiatic, antioxidative, antipyretic, anti-diabetic, anti-inflammatory and hepatoprotective properties are discussed. This comprehensive documentation will help researchers to better understand the medicinal uses of the herb. Further studies on B. ligulata can lead to the discovery of new drug(s) and therapeutics for various ailments.

Phylogeographic analysis of Saxifraga fortunei complex (Saxifragaceae) reveals multiple origins of morphological and ecological variations in the Japanese Archipelago.

Phenotypic polymorphism within a species is a notable phenomenon in evolutionary biology to understand the process of adaptive speciation and other historical events. The Saxifraga fortunei complex is a widespread herb found in East Asia. It includes several ecotypic taxa corresponding to their habitat environments. The distribution of the various ecotypes in a limited area of the Japanese Archipelago makes the species a suitable model to investigate the impact of population demographic history and natural selection on lineage diversification. Here, Sanger-based sequencing was used to estimate the divergence timeframe between populations of the Eurasian continent and Japan. Genome-wide SNPs obtained by ddRAD sequencing were used to investigate the phylogeographic origins of ecotypic taxa. The phylogenetic analyses revealed the divergence of the Japanese population from the continental population in the late Miocene. Two distinct regional clades of North and South Japan were identified; phenotypic diversification was evident only in the southern clade. The South Japan clades displayed a historical distribution expansion from north to south. The phenotypic variations appeared to have generated during the expansion. The ecotypic boundaries were incongruent with the genetic grouping. We propose that morphological and ecological specialization in Japanese populations was repeatedly generated by local natural selection.

Comparative analysis of spatial genetic structures in sympatric populations of two riparian plants, Saxifraga acerifolia and Saxifraga fortunei.

PREMISE: The genetic structure between plant populations is facilitated by the spatial population arrangement and limited dispersal of seed and pollen. Saxifraga acerifolia, a local endemic species in Japan, is a habitat specialist that is confined to waterfalls in riparian environments. Its sister species, Saxifraga fortunei, is a generalist that is widely distributed along riverbanks. Here, we examined sympatric populations of the two Saxifraga species to test whether the differences in habitat preference and colonization process influenced regional and local genetic structures. METHODS: To reveal genetic structures, we examined chloroplast microsatellite variations and genome-wide nucleotide polymorphisms obtained by genotyping by sequencing. We also estimated the gene flow among and within populations and performed landscape genetic analyses to evaluate seed and pollen movement and the extent of genetic isolation related to geographic distance and/or habitat differences. RESULTS: We found strong genetic structure in the specialist S. acerifolia, even on a small spatial scale (<1 km part); each population on a different waterfall in one river system had a completely different predominant haplotype. By contrast, the generalist S. fortunei showed no clear genetic differentiation. CONCLUSIONS: Our findings suggest that the level of genetic isolation was increased in S. acerifolia by the spatially fragmented habitat and limited seed and pollen dispersal over waterfalls. Habitat differentiation between the sister taxa could have contributed to the different patterns of gene flow and then shaped the contrasting genetic structures.

Preparative isolation of antioxidative gallic acid derivatives from Saxifraga tangutica using a class separation method based on medium-pressure liquid chromatography and reversed-phase liquid chromatography.

Saxifraga tangutica is widely used as a medicinal herb to treat hepatic diseases. Here, we developed a class separation method to separate gallic acid derivatives 1,1-diphenyl-2-picrylhydrazyl inhibitors from the methanol extract of Saxifraga tangutica. Firstly, an MCI GEL CHP20P medium-pressure liquid chromatography was used to pretreat the crude extract from Saxifraga tangutica (500 g) and the target sample (fraction Fr1, 1.7 g) was obtained. Then, an online reversed-phase liquid chromatography-1,1-diphenyl-2-picrylhydrazyl assay was employed for recognizing potential 1,1-diphenyl-2-picrylhydrazyl inhibitors and six 1,1-diphenyl-2-picrylhydrazyl inhibitors fractions were recognized from fraction Fr1. Subsequently, the six 1,1-diphenyl-2-picrylhydrazyl inhibitors fractions were isolated via a ReproSil-Pur C18 AQ preparative column. During the separation process, the hydrophilic liquid chromatography was used to enrich the target compounds (Fr1-3-1-1 and Fr1-3-1-2) from the fraction Fr1-3, which were hardly isolated only by one step reversed-phase liquid chromatography. Finally, six gallic acid derivatives were obtained and identified as gallic acid (Fr1-1-1), gallic acid 3-O-ß-D-glucoside (Fr1-1-2), protocatechuic acid (Fr1-2), 4-O-galloyl-(-)-shikimic acid (Fr1-3-1-1), 5-O-galloyl-(-)-shikimic acid (Fr1-3-1-2), and 3-O-galloyl-shikimic acid (Fr1-4), respectively. Thus, the present study indicated that this method was highly efficient for the preparative separation of gallic acid derivatives 1,1-diphenyl-2-picrylhydrazyl inhibitors from natural products.

Separation of constituents from Bergenia stracheyi (Hook. F. & Thoms.) Engl. by high-speed countercurrent chromatography with elution mode and its antidiabetic and antioxidant in vitro evaluation.

Diabetes, a metabolic disorder, is caused by a high blood sugar level. Diabetes is an increasing health issue and search for potent antidiabetic agents is desirable. Owing to its ethnomedicinal value, the Himalayan perennial herb Bergenia stracheyi (Hook. f. & Thoms.) Engl. (Saxifragaceae Juss) is used to treat diabetes. Herein, an efficient high-speed countercurrent chromatography with elution mode is reported for separation of active compounds from B. stracheyi. In current investigation, six main compounds including ß-arbutin (1), bergenin (2), 6-O-galloylarbutin (3), gallic acid (4), 11-O-galloylbergenin (5), and (-)-epicatechin 3-O-gallate (6) with above 95% purity were efficiently separated in a single run using biphasic tert-butyl methyl ether/n-butanol/methanol/water (1:3:1:5, v/v/v/v) solvent system. The structures of these compounds were characterized using spectral techniques and compared with the literature. Antidiabetic and antioxidant activities evaluation of the study samples showed that ß-arbutin (1) and 6-O-galloylarbutin (3) have a significant protective effect, especially at high dose against hydrogen peroxide induced oxidative injury. Our results might help further in-depth phytochemical and biological evaluation studies in search of potent antidiabetic compounds from B. stracheyi.

[Analysis of varieties and standards of Saxifragaceae medicinal plants used in Tibetan medicine].

On the basis of literatures and standards relating to Tibetan medicine, the varieties, origin, standards and efficacy of Saxifragaceae plant used in Tibetan medicine were summarized. According to the findings, 75 species(including varieties) in 8 genera of Saxifragaceae plants, involving 21 varieties, are used in Tibetan medicine. Among them, 9 commonly used varieties, namely Songdi, Sedi, Yajima, Aoledansaierbao, Jiansidawu, Saiguo, Katuer, Sangdi, Maoqinghong, are recorded in Chinese Pharmacopoeia, Ministry Standards for Tibetan Medicine, Tibetan Medicine Standards and other local standards, accounting for 42.9% of the total number of varieties. Tibetan names, Tibetan translation of Chinese names, as well as original plant of Tibetan medicine varieties are quite different in relevant Tibetan medicine standards and literatures, which resulted in common phenomena of synonym and homonym. The standards of most varieties only involve characters, and microscopic, physical and chemical identification, with low quality standards. Based on the results of the analysis, this paper suggests strengthening surveys on herbal textual research, resources and current utilization of Saxifragaceae plants used in Tibetan medicine, summarizing the varieties, establishing improved quality standards, and perfor-ming a comparative study on therapeutic material basis and biological activity of different original plants, in order to promote rational use of these medicinal plant resources, and ensuring the accuracy, safety, and effectiveness of clinical medication.

Analysis of six chloroplast genomes provides insight into the evolution of Chrysosplenium (Saxifragaceae).

BACKGROUND: Chrysosplenium L. (Saxifragaceae) is a genus of plants widely distributed in Northern Hemisphere and usually found in moist, shaded valleys and mountain slopes. This genus is ideal for studying plant adaptation to low light conditions. Although some progress has been made in the systematics and biogeography of Chrysosplenium, its chloroplast genome evolution remains to be investigated. RESULTS: To fill this gap, we sequenced the chloroplast genomes of six Chrysosplenium species and analyzed their genome structure, GC content, and nucleotide diversity. Moreover, we performed a phylogenetic analysis and calculated non-synonymous (Ka) /synonymous (Ks) substitution ratios using the combined protein-coding genes of 29 species within Saxifragales and two additional species as outgroups, as well as a pair-wise estimation for each gene within Chrysosplenium. Compared with the outgroups in Saxifragaceae, the six Chrysosplenium chloroplast genomes had lower GC contents; they also had conserved boundary regions and gene contents, as only the rpl32 gene was lost in four of the Chrysosplenium chloroplast genomes. Phylogenetic analyses suggested that the Chrysosplenium separated to two major clades (the opposite group and the alternate group). The selection pressure estimation (Ka/Ks ratios) of genes in the Chrysosplenium species showed that matK and ycf2 were subjected to positive selection. CONCLUSION: This study provides genetic resources for exploring the phylogeny of Chrysosplenium and sheds light on plant adaptation to low light conditions. The lower average GC content and the lacking gene of rpl32 indicated selective pressure in their unique habitats. Different from results previously reported, our selective pressure estimation suggested that the genes related to photosynthesis (such as ycf2) were under positive selection at sites in the coding region.

Degradation of key photosynthetic genes in the critically endangered semi-aquatic flowering plant Saniculiphyllum guangxiense (Saxifragaceae).

BACKGROUND: Plastid gene loss and pseudogenization has been widely documented in parasitic and mycoheterotrophic plants, which have relaxed selective constraints on photosynthetic function. More enigmatic are sporadic reports of pseudogenization and loss of important photosynthesis genes in lineages thought to be fully photosynthetic. Here we report the complete plastid genome of Saniculiphyllum guangxiense, a critically endangered and phylogenetically isolated plant lineage, along with genomic evidence of reduced chloroplast function. We also report 22 additional plastid genomes representing the diversity of its containing clade Saxifragales, characterizing gene content and placing variation in a broader phylogenetic context. RESULTS: We find that the plastid genome of Saniculiphyllum has experienced pseudogenization of five genes of the ndh complex (ndhA, ndhB, ndhD, ndhF, and ndhK), previously reported in flowering plants with an aquatic habit, as well as the surprising pseudogenization of two genes more central to photosynthesis (ccsA and cemA), contrasting with strong phylogenetic conservatism of plastid gene content in all other sampled Saxifragales. These genes participate in photooxidative protection, cytochrome synthesis, and carbon uptake. Nuclear paralogs exist for all seven plastid pseudogenes, yet these are also unlikely to be functional. CONCLUSIONS: Saniculiphyllum appears to represent the greatest degree of plastid gene loss observed to date in any fully photosynthetic lineage, perhaps related to its extreme habitat specialization, yet plastid genome length, structure, and substitution rate are within the variation previously reported for photosynthetic plants. These results highlight the increasingly appreciated dynamism of plastid genomes, otherwise highly conserved across a billion years of green plant evolution, in plants with highly specialized life history traits.

Anti-inflammatory activity of the extracts from Rodgersia podophylla leaves through activation of Nrf2/HO-1 pathway, and inhibition of NF-κB and MAPKs pathway in mouse macrophage cells.

OBJECTIVE: Recently, Rodgersia podophylla has been reported to exhibit anti-inflammatory activity. However, little is known about the potential mechanisms about its anti-inflammatory activity. We elucidated the anti-inflammatory mechanisms of leaves extracts from Rodgersia podophylla (RP-L) in RAW264.7 cells. MATERIALS AND METHODS: LPS-induced NO was measured by Griess and mRNA of pro-inflammatory mediators was analyzed by RT-PCR. Cell viability was measured using MTT assay. The protein level was analyzed by Western blot. RESULTS: RP-L significantly inhibited the production of the pro-inflammatory mediators such as NO, iNOS, IL-1ß and IL-6 in LPS-stimulated RAW264.7 cells. RP-L increased HO-1 expression in RAW264.7 cells, and the inhibition of HO-1 by ZnPP reduced the inhibitory effect of RP-L against LPS-induced NO production in RAW264.7 cells. Inhibition of p38, ROS and GSK3ß attenuated RP-L-mediated HO-1 expression. Inhibition of ROS inhibited p38 phosphorylation and GSK3ß expression induced by RP-L. In addition, inhibition of GSK3ß blocked RP-L-mediated p38 phosphorylation. RP-L induced nuclear accumulation of Nrf2, and inhibition of p38, ROS and GSK3ß abolished RP-L-mediated nuclear accumulation of Nrf2. Furthermore, RP-L blocked LPS-induced degradation of IκB-α and nuclear accumulation of p65. RP-L also attenuated LPS-induced phosphorylation of ERK1/2 and p38. In GC/MS analysis of RP-L, pyrogallol was detected as bioactive compound for anti-inflammatory activity of RP-L. Pyrogallol was observed to activate HO-1 expression through ROS/GSK3ß/p38/Nrf2/HO-1 signaling. CONCLUSIONS: Our results suggest that RP-L exerts potential anti-inflammatory activity by activating ROS/GSK3ß/p38/Nrf2/HO-1 signaling and inhibiting NF-κB and MAPK signaling in RAW264.7 cells. These findings suggest that RP-L may have great potential for the development of anti-inflammatory drug.

Ecological niche differences between two polyploid cytotypes of Saxifraga rosacea.

PREMISE: Different cytotypes of a species may differ in their morphology, phenology, physiology, and their tolerance of extreme environments. We studied the ecological niches of two subspecies of Saxifraga rosacea with different ploidy levels: the hexaploid Central European endemic subspecies sponhemica and the more widely distributed octoploid subspecies rosacea. METHODS: For both cytotypes, we recorded local environmental conditions and mean plant trait values in populations across their areas of distribution, analyzed their distributions by niche modeling, studied their performance at two transplant sites with contrasting conditions, and experimentally tested their cold resistance. RESULTS: Mean annual temperature was higher in hexaploid than in octoploid populations and experiments indicated that frost tolerance of the hexaploid is lower than that of the octoploid. Reproduction of octoploids from Central Europe was higher than that of hexaploids at a transplant site in subarctic Iceland, whereas the opposite was true in temperate Luxembourg, indicating adaptation of the octoploids to colder conditions. Temperature variables were also most important in niche models predicting the distribution of the two cytotypes. Genetic differences in survival among populations were larger for the octoploids than for the hexaploids in both field gardens, suggesting that greater genetic variability may contribute to the octoploid's larger distributional range. CONCLUSIONS: Our results support the hypotheses that different cytotypes may have different niches leading to spatial segregation, and that higher ploidy levels can result in a broader ecological niche and greater tolerance of more extreme conditions.

Effect of UV radiation and altitude characteristics on the functional traits and leaf optical properties in Saxifraga hostii at the alpine and montane sites in the Slovenian Alps.

UV radiation affects the biochemical, physiological and morphological responses of plants. The effect is most pronounced at high altitude, such as alpine regions, and low latitude environments. The effect of UV radiation is impacted by different environmental conditions including temperature. We examined the response of the alpine plant Saxifraga hostii Tausch subsp. hostii growing at two altitudes (montane, 1100 m a.s.l. and alpine, 1500 m a.s.l.) in the Slovenian Alps. Selected ecophysiological, anatomical and pigment analyses along with measurements of the leaf optical properties were carried out during the growing season from July to September. Plants were grown under two different UV levels, near-ambient UV (UV) and reduced UV (UV-) radiation, and temperature conditions were monitored at both altitudes. Saxifraga hostii exhibited high photochemical efficiency of photosystem II and stomatal conductance under near-ambient UV radiation in August, which indicates that it is a well-acclimated plant. In September, photochemical efficiency was higher under reduced UV at the alpine altitude which together with a lower photosynthetic pigment content indicate delayed senescence for plants growing under reduced UV. Most leaf tissue thicknesses were not affected by UV radiation and altitude difference. There was a trend of increased stomatal density and reduced stomatal length on both leaf surfaces under near-ambient UV in August. However, there was no effect of UV attenuation or location at the alpine or montane site on the content of UV-B absorbing compounds, which implies the plant's tolerance of UV-B radiation. Saxifraga hostii leaves showed high absorption in the UV spectrum at higher altitudes, as shown by their optical properties. This study shows that Saxifraga hostii is well-acclimated to ambient UV radiation and to the environmental conditions at both altitudes. The effect of UV radiation is impacted by site conditions and this produces diverse plant responses, which contribute to the specific functional traits of Saxifraga hostii in the high-altitude environment.