Developmentally controlled subcellular remodeling and VND-initiated vacuole-executed PCD module shape xylem-like cells in peat moss.

Peat moss (Sphagnum) is a non-vascular higher plant with unique xylem-like hyaline (H) cells that are accompanied by photosynthetic chlorophyllous cells. These cellular structures play crucial roles in water storage and carbon sequestration. However, it is largely unknown how peat moss develops the H cells. This study systematically explored the Sphagnum Developmental Cell Atlas and Lineage and classified leaf cell development into two lineages with six stages (S0-S5) based on changes in key cellular traits, including the formation of spiral secondary cell walls (S4) and the presence of water pores (S5). Cell lineage-specific subcellular remodeling was transcriptionally regulated during leaf development, and vacuole-mediated clearance of organelles and cell death led to mature dead H cells. Interestingly, expression of land plant conserved Vascular-related NAC Domain (VND) genes correlated with H cell formation. Overall, these results suggest that the origination of xylem-like H cells is related to VND, likely through the neofunctionalization of vacuole-mediated cell death to attempt xylem formation in peat moss, suggesting potential uncoupling of xylem and phloem cell origins. This study positions peat moss as a potential model organism for studying integrative evolutionary cell biology.

Ancient large-scale gene duplications and diversification in bryophytes illuminate the plant terrestrialization.

Large-scale gene duplications (LSGDs) are crucial for evolutionary adaptation and recurrent in vascular plants. However, the role of ancient LSGDs in the terrestrialization and diversification of bryophytes, the second most species-rich group of land plants, remains largely elusive due to limited sampling in bryophytes. Employing the most extensive nuclear gene dataset in bryophytes to date, we reconstructed a time-calibrated phylogenetic tree from 209 species, covering virtually all key bryophyte lineages, for phylogenomic analyses of LSGDs and diversification. We newly identified two ancient LSGDs: one in the most recent common ancestor (MRCA) of extant bryophytes and another in the MRCA of the majority of Jungermanniales s. lato. Duplicated genes from these two LSGDs show significant enrichment in photosynthesis-related processes and structures. Rhizoid-responsive ROOTHAIR DEFECTIVE SIX-LIKE (RSL) genes from ancient LSGDs are present in rhizoidless bryophytes, challenging assumptions about rhizoid absence mechanisms. We highlighted four major diversification rate upshifts, two of which slightly postdated LSGDs, potentially linked to the flourishing of gymnosperms and angiosperms and explaining over 80% of bryophyte diversity. Our findings, supported by extensive bryophyte sampling, highlight the significance of LSGDs in the early terrestrialization and diversification of bryophytes, offering new insights into land plant evolution.

Duck circovirus regulates the expression of duck CLDN2 protein by activating the MAPK-ERK pathway to affect its adhesion and infection.

Duck circovirus (DuCV) is widely recognized as a prominent virus in China's duck farming industry, known for its ability to cause persistent infections and significant immunosuppression, which can lead to an increased susceptibility to secondary infections, posing a significant threat to the duck industry. Moreover, clinical evidence also indicates the potential vertical transmission of the virus through duck embryos to subsequent generations of ducklings. However, the limited availability of suitable cell lines for in vitro cultivation of DuCV has hindered further investigation into the molecular mechanisms underlying its infection and pathogenicity. In this study, we observed that oral DuCV infection in female breeding ducks can lead to oviduct, ovarian, and follicular infections. Subsequently, the infection can be transmitted to the fertilized eggs, resulting in the emergence of virus-carrying ducklings upon hatching. In contrast, the reproductive organs of male breeding ducks were unaffected by the virus, thus confirming that vertical transmission of DuCV primarily occurs through infection in female breeding ducks. By analyzing transcriptome sequencing data from the oviduct, we focused on claudin-2, a gene encoding the tight junction protein CLDN2 located on the cell membrane, which showed significantly increased expression in DuCV-infected oviducts of female breeding ducks. Notably, CLDN2 was confirmed to interact with the unique structural protein of DuCV, namely capsid protein (Cap), through a series of experimental approaches including co-immunoprecipitation (co-IP), GST pull-down, immunofluorescence, and adhesion-blocking assays. Furthermore, we demonstrated that the Cap protein binds to the extracellular loop structural domains EL1 and EL2 of CLDN2. Subsequently, by constructing a series of truncated bodies of the CLDN2 promoter region, we identified the transcription factor SP5 for CLDN2. Moreover, we found that DuCV infection triggers the activation of the MAPK-ERK signaling pathway in DEF cells and ducks, leading to an upregulation of SP5 and CLDN2 expression. This process ultimately leads to the transportation of mature CLDN2 to the cell surface, thereby facilitating increased virus adherence to the target organs. In conclusion, we discovered that DuCV utilizes host CLDN2 proteins to enhance adhesion and infection in oviducts and other target organs. Furthermore, we elucidated the signaling pathways involved in the interaction between DuCV Cap proteins and CLDN2, which provides valuable insights into the molecular mechanism underlying DuCV's infection and vertical transmission. IMPORTANCE: Although duck circovirus (DuCV) poses a widespread infection and a serious hazard to the duck industry, the molecular mechanisms underlying DuCV infection and transmission remain elusive. We initially demonstrated vertical transmission of DuCV through female breeding ducks by simulating natural infection. Furthermore, a differentially expressed membrane protein CLDN2 was identified on the DuCV-infected oviduct of female ducks, and its extracellular loop structural domains EL1 and EL2 were identified as the interaction sites of DuCV Cap proteins. Moreover, the binding of DuCV Cap to CLDN2 triggered the intracellular MAPK-ERK pathway and activated the downstream transcription factor SP5. Importantly, we demonstrated that intracellular Cap also interacts with SP5, leading to upregulation of CLDN2 transcription and facilitating enhanced adherence of DuCV to target tissue, thereby promoting viral infection and transmission. Our study sheds light on the molecular mechanisms underlying vertical transmission of DuCV, highlighting CLDN2 as a promising target for drug development against DuCV infection.

A Synopsis of Dicranum Hedw. (Dicranaceae, Bryophyta) in China, with Special References to Four Species Newly Reported and Re-Evaluation of Dicranum psathyrum Klazenga.

Dicranum Hedw. is a highly diverse and widely distributed genus within Dicranaceae. The species diversity and distribution of this genus in China, however, remain not well known. A new revision of Dicranum in China using morphological and molecular phylogenetic methods confirms that China has 39 species, including four newly reported species, D. bardunovii Tubanova & Ignatova, D. dispersum Engelmark, D. schljakovii Ignatova & Tubanova, and D. spadiceum J.E.Zetterst. Dicranum psathyrum Klazenga is transferred to Dicranoloma (Renauld) Renauld as a new synonym of Dicranoloma fragile Broth. Two species, Dicranum brevifolium (Lindb.) Lindb. and D. viride (Sull. & Lesq.) Lindb. are excluded from the bryoflora of China. A key to the Chinese Dicranum species is also provided. These results indicate an underestimation of the distribution range of numerous Dicranum species, underscoring the need for further in-depth investigations into the worldwide Dicranum diversity.

Identification of a novel gene PpBCG1 that has a positive role in desiccation tolerance in the moss Physcomitrium patens.

Water-to-land transition is a hallmark of terrestrialization for land plants and requires molecular adaptation to resist water deficiency. Lineages- or species-specific genes are widespread across eukaryotes, and yet the majority of those are functionally unknown and not annotated. Recent studies have revealed that some of such genes could play a role in adapting to environmental stress responses. Here, we identified a novel gene PpBCG1 (Bryophyte Co-retained Gene 1) in the moss Physcomitrium patens that was responsive to dehydration and rehydration. Under de- and rehydration treatments, PpBCG1 was significantly co-expressed with the dehydrin-encoding gene PpDHNA. Microarray data revealed that PpBCG1 was highly expressed in tissues of spores, female organ archegonia, and mature sporophytes. In addition, the Ppbcg1 mutant showed reduced ability of dehydration tolerance, whose plants were accompanied by a relatively low level of chlorophyll content during recovery. Comprehensive transcriptomics uncovered a detailed set of regulatory processes that were affected by the PpBCG1 disruption. Moreover, experimental evidence showed that PpBCG1 might function in the antioxidant activity, abscisic acid (ABA) pathway, and intracellular calcium (Ca2+) homeostasis to resist desiccation. Together, our study provides insights into the roles of one bryophyte co-retained gene in the desiccation tolerance.

Is RNA editing truly absent in the complex thalloid liverworts (Marchantiopsida)? Evidence of extensive RNA editing from Cyathodium cavernarum.

RNA editing is a crucial modification in plants' organellar transcripts that converts cytidine to uridine (C-to-U; and sometimes uridine to cytidine) in RNA molecules. This post-transcriptional process is controlled by the PLS-class protein with a DYW domain, which belongs to the pentatricopeptide repeat (PPR) protein family. RNA editing is widespread in land plants; however, complex thalloid liverworts (Marchantiopsida) are the only group reported to lack both RNA editing and DYW-PPR protein. The liverwort Cyathodium cavernarum (Marchantiopsida, Cyathodiaceae), typically found in cave habitats, was newly found to have 129 C-to-U RNA editing sites in its chloroplast and 172 sites in its mitochondria. The Cyathodium genus, specifically C. cavernarum, has a large number of PPR editing factor genes, including 251 DYW-type PPR proteins. These DYW-type PPR proteins may be responsible for C-to-U RNA editing in C. cavernarum. Cyathodium cavernarum possesses both PPR DYW proteins and RNA editing. Our analysis suggests that the remarkable RNA editing capability of C. cavernarum may have been acquired alongside the emergence of DYW-type PPR editing factors. These findings provide insight into the evolutionary pattern of RNA editing in land plants.

Molecular Phylogenetics and the Evolution of Morphological Complexity in Aytoniaceae (Marchantiophyta).

Aytoniaceae are one of the largest families of complex thalloid liverworts (Marchantiopsida), consisting of about 70 species, with most species being distributed in temperate areas. However, the phylogeny and evolution of the morphological character of Aytoniaceae are still poorly understood. Here, we employed two chloroplast loci, specifically, rbcL and trnL-F, along with a 26S nuclear ribosomal sequence to reconstruct the phylogeny and track the morphological evolution of Aytoniaceae. Our results reveal that Aytoniaceae are monophyletic, and five monophyletic clades were recovered (i.e., Asterellopsis-Cryptomitrium, Calasterella, Mannia, Reboulia-Plagiochasma, and Asterella). Asterella was divided into five clades (i.e., Asterella lindenbergiana, subg. Saccatae, subg. Phragmoblepharis, subg. Wallichianae, and subg. Asterella), except for Asterella palmeri, which is the sister of Asterellopsis grollei. Bayesian molecular clock dating indicates that the five primary clades within Aytoniaceae underwent divergence events in the Cretaceous period. Asterellopsis differentiated during the early Upper Cretaceous (c. 84.2 Ma), and Calasterella originated from the late Lower Cretaceous (c. 143.0 Ma). The ancestral Aytoniaceae plant is reconstructed as the absence of a pseudoperianth, lacking equatorial apertures, and having both male and female reproductive organs on the main thallus. At present, Asterellopsis consists of two species known in Asia and America with the new transfer of Asterella palmeri to Asterellopsis. A new subgenus, Asterella subg. Lindenbergianae, is proposed.

Effect of duck interferon-α and an anti-cap protein polyclonal antibody against duck circovirus.

Duck circovirus (DuCV) is one of the most prevalent viruses in the duck breeding industry, and causes persistent infection and severe immunosuppression. Currently, there is a serious lack of prevention and control measures and no commercial vaccine against DuCV. Therefore, effective antiviral drugs are important for treating DuCV infection. Interferon (IFN) is an important component of antiviral innate immunity, but it remains unclear whether duck IFN-α has a clinical effect against DuCV. Antibody therapy is an important way to treat viral infections. The DuCV structural protein (cap) is immunogenic, and it remains to be determined whether an anti-cap protein antibody can effectively block DuCV infection. In this study, the duck IFN-α gene and the DuCV structural protein cap gene were cloned, expressed and purified in Escherichia coli to prepare duck recombinant IFN-α and the cap protein. Then, rabbits were immunized with the recombinant cap protein to prepare a rabbit polyclonal antibody. This study investigated the antiviral effect of duck recombinant IFN-α and the anti-cap protein antibody and their combined effect on Cherry Valley ducks infected with DuCV. The results showed that the treatment significantly alleviated the clinical symptoms of immune organ atrophy and immunosuppression compared with the control. The histopathological damage of the target organs was alleviated, and replication of DuCV in the immune organs was significantly inhibited. The treatment also reduced the damage caused by DuCV to the liver and immune function, and increased the level of the DuCV antibody in the blood, thereby improving antiviral activity. Notably, the combination of duck IFN-α and the polyclonal antibody completely blocked DuCV infection after 13 days under the experimental conditions, showing a better inhibitory effect on DuCV infection than single treatments. These results showed that duck recombinant IFN-α and the anti-cap protein antibody can be used as antiviral drugs to clinically treat and control DuCV infection, particularly the vertical transmission of the virus in breeding ducks.

The endomembrane system: how does it contribute to plant secondary metabolism?

New organelle acquisition through neofunctionalization of the endomembrane system (ES) with respect to plant secondary metabolism is a key evolutionary strategy for plant adaptation, which is overlooked due to the complexity of angiosperms. Bryophytes produce a broad range of plant secondary metabolites (PSMs), and their simple cellular structures, including unique organelles, such as oil bodies (OBs), highlight them as suitable model to investigate the contribution of the ES to PSMs. In this opinion, we review latest findings on the contribution of the ES to PSM biosynthesis, with a specific focus on OBs, and propose that the ES provides organelles and trafficking routes for PSM biosynthesis, transportation, and storage. Therefore, future research on ES-derived organelles and trafficking routes will provide essential knowledge for synthetic applications.

Stepwise changes in flavonoids in spores/pollen contributed to terrestrial adaptation of plants.

Protecting haploid pollen and spores against UV-B light and high temperature, 2 major stresses inherent to the terrestrial environment, is critical for plant reproduction and dispersal. Here, we show flavonoids play an indispensable role in this process. First, we identified the flavanone naringenin, which serves to defend against UV-B damage, in the sporopollenin wall of all vascular plants tested. Second, we found that flavonols are present in the spore/pollen protoplasm of all euphyllophyte plants tested and that these flavonols scavenge reactive oxygen species to protect against environmental stresses, particularly heat. Genetic and biochemical analyses showed that these flavonoids are sequentially synthesized in both the tapetum and microspores during pollen ontogeny in Arabidopsis (Arabidopsis thaliana). We show that stepwise increases in the complexity of flavonoids in spores/pollen during plant evolution mirror their progressive adaptation to terrestrial environments. The close relationship between flavonoid complexity and phylogeny and its strong association with pollen survival phenotypes suggest that flavonoids played a central role in the progression of plants from aquatic environments into progressively dry land habitats.

Hexavalent chromium disrupts the skin barrier by targeting ROS-mediated mitochondrial pathway apoptosis in keratinocytes.

Hexavalent chromium (Cr(VI)), a toxic heavy metal, is ubiquitous in daily life. Exposure to this toxic substance in occupational settings can cause dermatitis and cancer. As the body's largest organ, the skin plays a crucial role in protecting the organism against external aggressions. While previous studies have focused on the effects of Cr(VI) on skin inflammation, this study investigates the potential toxicity of Cr(VI) from the skin barrier and integrity perspective. The in vivo results of this study showed that mice exposed to Cr(VI) experienced skin deterioration and hemorrhaging, as well as a reduction in the thickness of the collagen fiber layer. TUNEL and Occludin staining results revealed that Cr(VI)'s toxicity primarily targeted keratinocytes. Experiments in vitro demonstrated that Cr(VI) treatment decreased the activity of HaCaT cells, altered cell morphology, and increased LDH secretion. Further research revealed that Cr(VI) could modify membrane permeability, impair membrane integrity, and reduce the protein expression of ZO-1 and Occludin. In addition, it was discovered that Cr(VI) promoted cell apoptosis and inhibited AKT activation. However, the addition of a caspase inhibitor and an AKT activator prevented Cr(VI)-induced injury to the cell membrane barrier, indicating that apoptosis plays a crucial role in this process. The addition of three apoptotic pathway inhibitors, confirmed that Cr(VI) damaged the cell barrier through ROS-mediated mitochondrial pathway apoptosis. Moreover, the use of a ROS inhibitor significantly reduced Cr(VI)-induced apoptosis and cell barrier injury. In conclusion, this study provides an experimental foundation for the treatment of skin injury caused by Cr(VI).

Comparison study of protective effects of porcine bile acids and sheep bile acids against heat stress in chickens.

BACKGROUND: Heat stress (HS) is known to exert negative effects on the poultry and breeding industry, resulting in severe economic losses. Bile acids (BAs), an important component of bile, play a crucial role in improving the production performance of livestock and poultry, alleviating stress injury, and ensuring the health of livestock and poultry. At present, porcine BAs are widely used because of their therapeutic effects on HS; however, it remains unclear whether the same effects are exerted by sheep BAs, which are different from porcine BAs and have different compositions. In this study, we compared the anti-HS effects of porcine BAs and sheep BAs in the diet by establishing an HS model of chicks and investigating the chicken performance, HS-related genes' expression, oxidative stress markers, jejunal histoarchitecture, inflammatory cytokines' expression, jejunal secreted immunoglobulin A concentration, and cecal bacterial flora. RESULTS: The results showed that the addition of sheep BAs to the diet increased the average daily weight gain and the feed conversion ratio of chicks. Under HS, sheep BAs were more effective than porcine BAs in improving the activities of lactate dehydrogenase and glutamic pyruvic transaminase in serum and the content/activity of malondialdehyde, superoxide dismutase, and reduced glutathione in serum and tissue, in reducing the messenger RNA (mRNA) expression of heat shock proteins (HSP60, HSP70, and HSP90) in the liver and jejunum, and in improving the histological structure and the expression of tight junction proteins (occludin and zonula occludens-1) and enriching intestinal bacterial flora. However, porcine BAs were significantly inferior to sheep BAs in reducing the mRNA expression of inflammatory factors (interleukin-6, interleukin-1ß, and tumor necrosis factor-α). CONCLUSION: The effect of sheep BAs was more significant than porcine BAs was in alleviating HS injury in chicks, suggesting that sheep BAs have great potential as new feed nutrition and health additive to improve poultry production performance and prevent HS. © 2023 Society of Chemical Industry.

Pathogenicity of duck circovirus and fowl adenovirus serotype 4 co-infection in Cherry Valley ducks.

Duck circovirus (DuCV) is one of the most prevalent infectious viruses in the duck industry in China. Although the clinical symptoms vary, it often causes immunosuppression in the host and leads to secondary infection with other pathogens. Fowl adenovirus serotype 4 (FAdV-4) mainly infects chickens and causes hydropericardium hepatitis syndrome. However, the incidence of infection in ducks has increased in recent years, and the phenomenon of mixed infection with DuCV is very common, resulting in more severe clinical morbidity. However, there is no systematic study evaluating the presence of mixed infection. To explore the synergistic pathogenicity of DuCV and FAdV-4 co-infection in Cherry Valley ducks, a comparative experiment was established between DuCV and FAdV-4 co-infection and single infection animal models. It was found that DuCV and FAdV-4 co-infected ducks showed more pronounced clinical signs of pericardial effusion, hepatitis and immunosuppression; more severe tissue damage in target organs; and more significant levels of viral load, biochemical indicators and immune indicators in various organs compared with Cherry Valley ducks infected with just one virus. The results showed that co-infection with DuCV and FAdV-4 may promote greater viral replication, causing more severe tissue damage and immunosuppression than infection with just one virus. Therefore, the monitoring and prevention of the two viruses should be strengthened clinically, with a particular focus on the potential harm of DuCV as it carries the highest infection rate.

The role of transforming growth factor beta-1 protein in Escherichia coli secondary infection induced by H9N2 avian influenza virus in chickens.

The H9N2 subtype of avian influenza virus (AIV) is common in poultry production. It causes mild clinical signs but rarely leads to poultry mortalities. However, higher mortality can occur in chickens with co-infections, especially avian pathogenic Escherichia coli (APEC), which results in huge economic losses for the poultry industry. Unfortunately, the mechanism of co-infection remains unknown. Our previous studies screened several proteins associated with bacterial adhesion, including transforming growth factor beta-1 (TGF-ß1), integrins, cortactin, E-cadherin, vinculin, and fibromodulin. Herein, we investigated the contribution of TGF-ß1 to APEC adhesion after H9N2 infection. We first infected H9N2 and APEC in chicken, chicken embryo and DF-1 cells, and demonstrated that H9N2 infection promotes APEC adhesion to hosts in vitro and in vivo by plate count method. Through real-time fluorescence quantification and enzyme-linked immunosorbent assay, it was demonstrated that H9N2 infection not only increases TGF-ß1 expression but also its activity in a time-dependent manner. Then, through exogenous addition of TGF-ß1 and overexpression, we further demonstrated that TGF-ß1 can increase the adhesion of endothelial cells to DF-1 cells. Furthermore, the capacity of APEC adhesion to DF-1 cells was significantly decreased either by adding a TGF-ß1 receptor inhibitor or using small interfering RNAs to interfere with the expression of TGF-ß1. To sum up, H9N2 infection can promote the upregulation of TGF-ß1 and then increase the adhesion ability of APEC. Targeting TGF-ß1 and its associated pathway will provide valuable insights into the clinical treatment of E. coli secondary infection induced by H9N2 infection.

Evaluation of the antiviral effect of four plant polysaccharides against duck circovirus.

Recently, outbreaks of duck circovirus (DuCV) are frequently occurring worldwide due to secondary infections caused by post infection-induced immunosuppression. Due to a lack of preventive drugs and vaccines, the waterfowl industry losses are ever increasing. In this study, we extracted Astragalus polysaccharides (APS), pine pollen polysaccharides (PPPS), Aloe vera polysaccharides (AVE), and Ficus carica polysaccharides (FCPS) from Astragalus, pine pollen, aloe, and F. carica leaves, respectively. We randomly divided 150 one-day-old Cherry Valley ducks into five groups, which were inoculated with the DuCV solution and orally administered APS, PPPS, AVE, FCPS, and phosphate buffer saline (PBS), respectively. We collected the duck immune organs and serum samples at 8, 16, 24, 32, 40, and 48 days post-infection (dpi). Using clinical symptom analysis, molecular biology experiments, and serological experiments, we proved that plant polysaccharides could (a) improve the duck immunity, (b) reduce the viral load, and (c) mitigate DuCV-induced damage to immune organs, with both APS and PPPS having significant effects. Moreover, we detected viral load and cytokines within the first 8 dpi. Since the body's innate immunity could inhibit viral replication within five days of virus infection, 1-5 dpi was the best treatment time. Among the four polysaccharides showing in vitro anti-apoptotic activity, APS and PPPS significantly inhibited the DuCV infection-induced apoptosis of peripheral blood lymphocytes. Overall, since our findings show APS and PPPS having significant anti-DuCV effects both in vivo and in vitro, they can be promising candidates for preventing DuCV infection in ducks.

Will climate change cause the global peatland to expand or contract? Evidence from the habitat shift pattern of Sphagnum mosses.

Peatlands play a crucial role in the global carbon cycle. Sphagnum mosses (peat mosses) are considered to be the peatland ecosystem engineers and contribute to the carbon accumulation in the peatland ecosystems. As cold-adapted species, the dominance of Sphagnum mosses in peatlands will be threatened by climate warming. The response of Sphagnum mosses to climate change is closely related to the future trajectory of carbon fluxes in peatlands. However, the impact of climate change on the habitat suitability of Sphagnum mosses on a global scale is poorly understood. To predict the potential impact of climate change on the global distribution of Sphagnum mosses, we used the MaxEnt model to predict the potential geographic distribution of six Sphagnum species that dominate peatlands in the future (2050 and 2070) under two greenhouse gas emission scenarios (SSP1-2.6 and SSP5-8.5). The results show that the mean temperature of the coldest quarter, precipitation of the driest month, and topsoil calcium carbonate are the main factors affecting the habitat availability of Sphagnum mosses. As the climate warms, Sphagnum mosses tend to migrate northward. The suitable habitat and abundance of Sphagnum mosses increase extensively in the high-latitude boreal peatland (north of 50°N) and decrease on a large scale beyond the high-latitude boreal peatland. The southern edge of boreal peatlands would experience the greatest decline in the suitable habitat and richness of Sphagnum mosses with the temperature rising and would be a risk area for the transition from carbon sink to carbon source. The spatial-temporal pattern changes of Sphagnum mosses simulated in this study provide a reference for the development of management and conservation strategies for Sphagnum bogs.

New insights into the phylogeny of the complex thalloid liverworts (Marchantiopsida) based on chloroplast genomes.

Marchantiopsida (complex thalloid liverworts) are one of the earliest lineages of embryophytes (land plants), and well-known for their air pores and chambers, pegged rhizoids, and absence of organellular RNA editing sites. Despite their importance to an understanding of early embryophyte evolution, many key nodes within this class remain poorly resolved, owing to the paucity of genetic loci previously available for phylogenetic analyses. Here, we sequenced 54 plastomes, representing 28 genera, nearly all families, and all orders of Marchantiopsida. Based on these plastomes, we present a hypothesis of deep relationships within the class, and make the first investigations of gene contents and synteny. Overall, the Marchantiopsida plastomes were well-conserved, with the exception of the genus Cyathodium that has plastomes with higher GC content, fewer single sequence repeats (SSRs), and more structural variations, implying that this genus might possess RNA editing sites. Abundant repetitive elements and six highly divergent regions were identified as suitable for future infrafamilial taxonomic studies. The phylogenetic topology of Sphaerocarpales, Neohodgsoniales and Blasiales within Marchantiopsida was essentially congruent with previous studies but generally we obtained higher support values. Based on molecular evidence and previous morphological studies, we include Lunulariales in Marchantiales and suggest the retention of narrowed delimitation of monotypic families. The phylogenetic relationships within Marchantiales were better resolved, and 13 monophyletic families were recovered. Our analyses confirmed that the loss of intron 2 of ycf3 is a synapomorphy of Marchantiidae. Finally, we propose a new genus, Asterellopsis (Aytoniaceae), and present an updated classification of Marchantiopsida. The highly supported phylogenetic backbone provided here establishes a framework for future comparative and evolutionary studies of the complex thalloid liverworts.

Vacuoles in Bryophytes: Properties, Biogenesis, and Evolution.

Vacuoles are the most conspicuous organelles in plants for their indispensable functions in cell expansion, solute storage, water balance, etc. Extensive studies on angiosperms have revealed that a set of conserved core molecular machineries orchestrate the formation of vacuoles from multiple pathways. Usually, vacuoles in seed plants are classified into protein storage vacuoles and lytic vacuoles for their distinctive morphology and physiology function. Bryophytes represent early diverged non-vascular land plants, and are of great value for a better understanding of plant science. However, knowledge about vacuole morphology and biogenesis is far less characterized in bryophytes. In this review, first we summarize known knowledge about the morphological and metabolic constitution properties of bryophytes' vacuoles. Then based on known genome information of representative bryophytes, we compared the conserved molecular machinery for vacuole biogenesis among different species including yeast, mammals, Arabidopsis and bryophytes and listed out significant changes in terms of the presence/absence of key machinery genes which participate in vacuole biogenesis. Finally, we propose the possible conserved and diverged mechanism for the biogenesis of vacuoles in bryophytes compared with seed plants.

A Novel Predictive Model for Adrenocortical Carcinoma Based on Hypoxia- and Ferroptosis-Related Gene Expression.

Background: The impact of hypoxia on ferroptosis is important in cancer proliferation, but no predictive model combining hypoxia and ferroptosis for adrenocortical carcinoma (ACC) has been reported. The purpose of this study was to construct a predictive model based on hypoxia- and ferroptosis-related gene expression in ACC. Methods: We assessed hypoxia- and ferroptosis-related gene expression using data from 79 patients with ACC in The Cancer Genome Atlas (TCGA). Then, a predictive model was constructed to stratify patient survival using least absolute contraction and selection operation regression. Gene expression profiles of patients with ACC in the Gene Expression Omnibus (GEO) database were used to verify the predictive model. Results: Based on hypoxia-related gene expression, 79 patients with ACC in the TCGA database were divided into three molecular subtypes (C1, C2, and C3) with different clinical outcomes. Patients with the C3 subtype had the shortest survival. Ferroptosis-related genes exhibited distinct expression patterns in the three subtypes. A predictive model combining hypoxia- and ferroptosis-related gene expression was constructed. A nomogram was constructed using age, sex, tumor stage, and the predictive gene model. Gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses revealed that the gene signature was mainly related to the cell cycle and organelle fission. Conclusion: This hypoxia-and ferroptosis-related gene signature displayed excellent predictive performance for ACC and could serve as an emerging source of novel therapeutic targets in ACC.

Anti-tumor activity of polysaccharides extracted from Pinus massoniana pollen in colorectal cancer- in vitro and in vivo studies.

The prevalence and mortality rate of colorectal cancer (CRC) have been increasing dramatically worldwide. Pinus massoniana pollen, a well-known natural food, is one of the most commonly consumed traditional medicines in China. P. massoniana pollen polysaccharides (PPPS) have antitumor effects, but it remains unclear whether they can inhibit CRC. Here, we have demonstrated that PPPS inhibited CRC cell proliferation effectively, induced morphology changes, triggered apoptosis by upregulating key apoptosis-related proteins, and arrested the cell cycle at the G0/G1 phase. Moreover, PPPS markedly inhibited CRC cell metastasis by downregulating MMP-9 and inhibiting epithelial-mesenchymal transition. In vivo, PPPS exhibited potent antitumor activity and no observable toxicity in BALB/c nude mice bearing HCT-116 tumors. Most strikingly, PPPS pre-treatment dramatically inhibited the growth of incipient tumors, although not as effectively as in the PPPS-Ther group. Thus, our results suggest that PPPS can be a potential anti-CRC agent, paving the way for developing complex carbohydrates for tumor prevention and treatment.