[Progress of researches on developmental processes and reproduction mode of Pneumocystis].

Pneumocystis, an important opportunistic fungal pathogen that parasitizes in multiple mammalian lungs, may cause life-threatening Pneumocystis pneumonia (PCP) and even death among immunocompromised individuals. With the rapid development of high-throughput sequencing and multi-omics technologies, systematic comparative analyses of genome, transcriptome, and whole-genome sequencing results demonstrate that Pneumocystis is a type of obligate biotrophic fungi, and requires obtaining nutrition from hosts. In addition, sexual reproduction is an essential process for Pneumocystis survival, production and transmission, and asexual reproduction facilitates Pneumocystis survival, which provides new insights into understanding of the whole developmental process of Pneumocystis in the host lung and inter-host transmission of Pneumocystis. This review summarizes the advances in the reproduction mode of Pneumocystis and underlying mechanisms, which provides insights into prevention and treatment of PCP, notably for the prophylaxis against nosocomial transmission of PCP.

Progress of researches on developmental processes and reproduction mode of Pneumocystis / 中国血吸虫病防治杂志

Pneumocystis, an important opportunistic fungal pathogen that parasitizes in multiple mammalian lungs, may cause life-threatening Pneumocystis pneumonia (PCP) and even death among immunocompromised individuals. With the rapid development of high-throughput sequencing and multi-omics technologies, systematic comparative analyses of genome, transcriptome, and whole-genome sequencing results demonstrate that Pneumocystis is a type of obligate biotrophic fungi, and requires obtaining nutrition from hosts. In addition, sexual reproduction is an essential process for Pneumocystis survival, production and transmission, and asexual reproduction facilitates Pneumocystis survival, which provides new insights into understanding of the whole developmental process of Pneumocystis in the host lung and inter-host transmission of Pneumocystis. This review summarizes the advances in the reproduction mode of Pneumocystis and underlying mechanisms, which provides insights into prevention and treatment of PCP, notably for the prophylaxis against nosocomial transmission of PCP.

Genetic variation and population structure of clonal Zingiber zerumbet at a fine geographic scale: a comparison with two closely related selfing and outcrossing Zingiber species.

BACKGROUND: There has always been controversy over whether clonal plants have lower genetic diversity than plants that reproduce sexually. These conflicts could be attributed to the fact that few studies have taken into account the mating system of sexually reproducing plants and their phylogenetic distance. Moreover, most clonal plants in these previous studies regularly produce sexual progeny. Here, we describe a study examining the levels of genetic diversity and differentiation within and between local populations of fully clonal Zingiber zerumbet at a microgeographical scale and compare the results with data for the closely related selfing Z. corallinum and outcrossing Z. nudicarpum. Such studies could disentangle the phylogenetic and sexually reproducing effect on genetic variation of clonal plants, and thus contribute to an improved understanding in the clonally reproducing effects on genetic diversity and population structure. RESULTS: The results revealed that the level of local population genetic diversity of clonal Z. zerumbet was comparable to that of outcrossing Z. nudicarpum and significantly higher than that of selfing Z. corallinum. However, the level of microgeographic genetic diversity of clonal Z. zerumbet is comparable to that of selfing Z. corallinum and even slightly higher than that of outcrossing Z. nudicarpum. The genetic differentiation among local populations of clonal Z. zerumbet was significantly lower than that of selfing Z. corallinum, but higher than that of outcrossing Z. nudicarpum. A stronger spatial genetic structure appeared within local populations of Z. zerumbet compared with selfing Z. corallinum and outcrossing Z. nudicarpum. CONCLUSIONS: Our study shows that fully clonal plants are able not only to maintain a high level of within-population genetic diversity like outcrossing plants, but can also maintain a high level of microgeographic genetic diversity like selfing plant species, probably due to the accumulation of somatic mutations and absence of a capacity for sexual reproduction. We suggest that conservation strategies for the genetic diversity of clonal and selfing plant species should be focused on the protection of all habitat types, especially fragments within ecosystems, while maintenance of large populations is a key to enhance the genetic diversity of outcrossing species.

The Pacific Tree-Parasitic Fungus Cyclocybe parasitica Exhibits Monokaryotic Fruiting, Showing Phenotypes Known from Bracket Fungi and from Cyclocybe aegerita.

Cyclocybe parasitica is a wood-destroying parasitic edible mushroom growing on diverse broad-leafed trees in New Zealand and other Pacific areas. Recent molecular systematics of European Cyclocybe aegerita, a newly delimited Asian phylum and of related species, corroborated the distinction of the chiefly saprobic cultivated edible mushroom C. aegerita from C. parasitica. Here, we show that C. parasitica exhibits a morpho-physiological trait characteristic to its European cousin, i.e., monokaryotic fruiting sensu stricto (basidiome formation without mating). Monokaryotic fruiting structures formed by C. parasitica ICMP 11668-derived monokaryons were categorized into four phenotypes. One of them displays ulcer-like structures previously reported from bracket fungi. Histology of dikaryotic and monokaryotic C. parasitica fruiting structures revealed anatomical commonalities and differences between them, and towards monokaryotic fruiting structures of C. aegerita. Mating experiments with C. parasitica strains representative of each fruiting phenotype identified compatible sibling monokaryons. Given reports on hypothetically monokaryotic basidiome field populations of 'C. aegerita sensu lato', it seems worthwhile to prospectively investigate whether monokaryotic fruiting s.str. occurs in nature. Sampling from such populations including karyotyping, comparative -omics, and competition assays may help to answer this question and provide evidence whether this trait may confer competitive advantages to a species capable of it.

Warming enhances the cadmium toxicity on macrophyte Myriophyllum aquaticum (Vell.) Verd. seedlings.

Due to a close contact with water column, submerged macrophytes are easily disturbed by environment change in freshwater ecosystems, especially at the seedling stage. In recent decades, freshwater ecosystems have been subject to severe cadmium (Cd) pollution, which can cause toxic effects on the growth of submerged macrophytes. Moreover, the temperature rise resulting from climate warming and water level decline may further aggravate such effect, especially in shallow lakes. Here, we investigated the independent and interaction effects of Cd exposure levels (0, 0.5, 1, and 2.5 mg L-1) and temperature (15, 25, and 30 °C) on morphological and physiological traits of Myriophyllum aquaticum (Vell.) Verd. Seedlings generated from propagules and seeds. The temperature rise and Cd exposure generally resulted in a significant increase of Cd concentrations and antioxidant enzyme activities in leaves, as well as a decrease of chlorophyll a and b concentrations. The number and length of leaves generated from propagules always show a downward trend with the increase of Cd exposure, regardless of the temperature. Moreover, the lowest leaf number and length always occurred at high temperature (i.e. 30 °C) when the Cd exposure level increased to 1 and 2.5 mg L-1. For the seedlings generated from seeds, the temperature rise caused an increase of leaf emergence rate under low Cd exposure levels, but resulted in a significant decrease with the Cd exposure level. This study indicates the negative effects of Cd exposure and temperature rise on submerged macrophytes at the seedling stage, and highlights that temperature rise would enhance Cd toxicity.

Unlocking the Door of Boosting Biodirected Structures for High-Performance VN x O y /C by Controlling the Reproduction Mode.

Diverse reproduction modes of bio-organisms open new intriguing opportunities for biochemistry-enabled materials. Herein, a new strategy is developed to explore biodirected structures for functional materials via controlling the reproduction mode. Yeast with sexual or asexual reproduction mode are employed in this work. They result in two different biodirected structures, from bowl-like hollow hemisphere to "bubble-in-sphere" (BIS) structure, for the VN x O y /C composites. Benefitting from the hierarchical structure, nanoscale particles and conductive biomass-derived carbon base, both VN x O y /C biocomposites achieve high power/energy density, good reliability, and excellent long-term cycling stability in aqueous Zn-ion batteries. Deep investigations further reveal that different biodirected structures greatly influence the electrochemical properties of biocomposites. The bowl-like structures with thin shells and folded double layers achieve larger surface area and more active sites, which ensure their faster kinetics and better high rate capability. The BIS structures with a more compact assembly and higher stack capability are favorable to the better energy storage. Therefore, this work not only introduces a new clue to boost biodirected structures for functional materials, but also propels the development of Zn-ion batteries in diverse applications.

Characterization of the satellitome in lower vascular plants: the case of the endangered fern Vandenboschia speciosa.

BACKGROUND AND AIMS: Vandenboschia speciosa is a highly vulnerable fern species, with a large genome (10.5 Gb). Haploid gametophytes and diploid sporophytes are perennial, can reproduce vegetatively, and certain populations are composed only of independent gametophytes. These features make this fern a good model: (1) for high-throughput analysis of satellite DNA (satDNA) to investigate possible evolutionary trends in satDNA sequence features; (2) to determine the relative contribution of satDNA and other repetitive DNAs to its large genome; and (3) to analyse whether the reproduction mode or phase alternation between long-lasting haploid and diploid stages influences satDNA abundance or divergence. METHODS: We analysed the repetitive fraction of the genome of this species in three different populations (one comprised only of independent gametophytes) using Illumina sequencing and bioinformatic analysis with RepeatExplorer and satMiner. KEY RESULTS: The satellitome of V. speciosa is composed of 11 satDNA families, most of them showing a short repeat length and being A + T rich. Some satDNAs had complex repeats composed of sub-repeats, showing high similarity to shorter satDNAs. Three families had particular structural features and highly conserved motifs. SatDNA only amounts to approx. 0.4 % of its genome. Likewise, microsatellites do not represent more than 2 %, but transposable elements (TEs) represent approx. 50 % of the sporophytic genomes. We found high resemblance in satDNA abundance and divergence between both gametophyte and sporophyte samples from the same population and between populations. CONCLUSIONS: (1) Longer (and older) satellites in V. speciosa have a higher A + T content and evolve from shorter ones and, in some cases, microsatellites were a source of new satDNAs; (2) the satellitome does not explain the huge genome size in this species while TEs are the major repetitive component of the V. speciosa genome and mostly contribute to its large genome; and (3) reproduction mode or phase alternation between gametophytes and sporophytes does not entail accumulation or divergence of satellites.

[Population structure and regeneration strategy of relict deciduous broadleaved trees on Mount Tianmu, Zhejiang Province, China.] / æµ™æ±Ÿå¤©ç›®å±±å­‘é—è½å¶é˜”å¶æ ‘ç§çš„ç§ç¾¤ç»“æž„åŠæ›´æ–°ç­–ç•¥.

The population structure, regeneration ways and spatial relationships of six relict deci-duous broadleaved trees were examined based on community investigation on Mount Tianmu, East China. The results showed that relict deciduous broadleaved trees had a strong ability of vegetative reproduction and their population structure was generally belonged to intermittent type. Some relict species such as Cyclocarya paliurus and Liquidamb aracalycina regenerated discontinuously at appropriate sites via long-distance diffusion. Some species such as Emmenoptery henryi and Euptelea pleiospermum regenerated discontinuously around mature trees due to habitat limitation and frequent disturbance. After occupying forest gaps by seedling regeneration, C. paliurus, L. acalycina, Nyssasinensis and Liquidambar formosana could recruit and form multi-stemmed individuals by their inherent sprouting ability at relatively stable sites such as crest slope and side slope. At riverbed, valley slope and head hollow, recognized as unstable habitats, Emmenopterys henryi, E. pleiospermum, and L. formosana could also recruit by strong sprouting ability due to sparse seedlings and individual loss incurred by disturbance. Therefore, the relict deciduous broadleaved trees could be classified into two ecological species groups (repairment species for forest gap and supplement species for special habitat) based on spatial distribution and strategy of regeneration and competition. We suggested that the protection of special habitats of their communities should be strengthened.

Photoperiod Extension Enhances Sexual Megaspore Formation and Triggers Metabolic Reprogramming in Facultative Apomictic Ranunculus auricomus.

Meiosis, the key step of sexual reproduction, persists in facultative apomictic plants functional to some extent. However, it still remains unclear how and why proportions of reproductive pathways vary under different environmental stress conditions. We hypothesized that oxidative stress mediates alterations of developmental pathways. In apomictic plants we expected that megasporogenesis, the stage directly after meiosis, would be more affected than later stages of seed development. To simulate moderate stress conditions we subjected clone-mates of facultative apomictic Ranunculus auricomus to 10 h photoperiods, reflecting natural conditions, and extended ones (16.5 h). Reproduction mode was screened directly after megasporogenesis (microscope) and at seed stage (flow cytometric seed screening). Targeted metabolite profiles were performed with HPLC-DAD to explore if and which metabolic reprogramming was caused by the extended photoperiod. Prolonged photoperiods resulted in increased frequencies of sexual vs. aposporous initials directly after meiosis, but did not affect frequencies of sexual vs. asexual seed formation. Changes in secondary metabolite profiles under extended photoperiods affected all classes of compounds, and c. 20% of these changes separated the two treatments. Unexpectedly, the renowned antioxidant phenylpropanoids and flavonoids added more to clone-mate variation than to treatment differentiation. Among others, chlorophyll degradation products, non-assigned phenolic compounds and more lipophilic metabolites also contributed to the dissimilarity of the metabolic profiles of plants that had been exposed to the two different photoperiods. The hypothesis of moderate light stress effects was supported by increased proportions of sexual megaspore development at the expense of aposporous initial formation. The lack of effects at the seed stage confirms the basic assumption that only meiosis and sporogenesis would be sensitive to light stress. The concomitant change of secondary metabolite profiles, as a systemic response at this early developmental stage, supports the notion that oxidative stress could have affected megasporogenesis by causing the observed metabolic reprogramming. Hypotheses of genotype-specific responses to prolonged photoperiods are rejected.

When sexual meets apomict: genome size, ploidy level and reproductive mode variation of Sorbus aria s.l. and S. austriaca (Rosaceae) in Bosnia and Herzegovina.

BACKGROUND AND AIMS: Allopolyploidy and intraspecific heteroploid crosses are associated, in certain groups, with changes in the mating system. The genus Sorbus represents an appropriate model to study the relationships between ploidy and reproductive mode variations. Diploid S. aria and tetraploid apomictic S. austriaca were screened for ploidy and mating system variations within pure and sympatric populations in order to gain insights into their putative causalities. METHODS: Flow cytometry was used to assess genome size and ploidy level among 380 S. aria s.l. and S. austriaca individuals from Bosnia and Herzegovina, with 303 single-seed flow cytometric seed screenings being performed to identify their mating system. Pollen viability and seed set were also determined. KEY RESULTS: Flow cytometry confirmed the presence of di-, tri- and tetraploid cytotype mixtures in mixed-ploidy populations of S. aria and S. austriaca. No ploidy variation was detected in single-species populations. Diploid S. aria mother plants always produced sexually originated seeds, whereas tetraploid S. austriaca as well as triploid S. aria were obligate apomicts. Tetraploid S. aria preserved sexuality in a low portion of plants. A tendency towards a balanced 2m : 1p parental genome contribution to the endosperm was shared by diploids and tetraploids, regardless of their sexual or asexual origin. In contrast, most triploids apparently tolerated endosperm imbalance. CONCLUSIONS: Coexistence of apomictic tetraploids and sexual diploids drives the production of novel polyploid cytotypes with predominantly apomictic reproductive modes. The data suggest that processes governing cytotype diversity and mating system variation in Sorbus from Bosnia and Herzegovina are probably parallel to those in other diversity hotspots of this genus. The results represent a solid contribution to knowledge of the reproduction of Sorbus and will inform future investigations of the molecular and genetic mechanisms involved in triggering and regulating cytotype diversity and alteration of reproductive modes.