青岛胶州湾四种类型湿地AM真菌多样性

对青岛胶州湾4种类型湿地（盐田、滩涂、湖泊和河口）中芦苇Phragmites communis、香蒲Typha orientalis和碱蓬Suaeda glauca 根围土壤中丛枝菌根（arbuscular mycorrhizal,AM）真菌进行孢子分离与鉴定,分析湿地生态系统中植物根围AM真菌群落特征。共分离到AM真菌5属10种,包括斗管囊霉属Funneliformis 2种、无梗囊霉属Acaulospora 3种、近明球囊霉属Claroideoglomus 2种、球囊霉属Glomus 1种、巨孢囊霉属Gigaspora 2种,其中,斗管囊霉属Funneliformis及地斗管囊霉Funneliformis geosporum的分离频度和相对多度最高,分别为湿地中AM真菌优势属和优势种。滩涂和河口湿地中植物AM真菌侵染率显著高于湖泊和盐田湿地植物,AM真菌孢子密度以滩涂湿地最高（572个/20mL）,湖泊湿地最低（220个/20mL）;滩涂湿地的种丰度和Shannon-Wiener指数最高,分别为3.8和1.2。从植物种类来看,AM真菌侵染率总体呈现出香蒲>碱蓬>芦苇,AM真菌孢子密度以香蒲最高,芦苇最低,植物种类对AM真菌种丰度和Shannon-Wiener指数影响不显著（P>0.05）。二因素方差分析和典型RDA相关分析表明,寄主植物种类对AM真菌孢子密度有一定影响,但湿地类型对AM真菌多样性的影响更为显著（P<0.05）,胶州湾湿地土壤因子Ca ²⁺、速效P含量与AM真菌孢子密度、物种丰度和多样性指数显著负相关,而速效K、Na ⁺、pH与其显著正相关。结果表明植物种类主要影响AM真菌孢子密度,AM真菌多样性受植物种类和湿地类型综合影响,滩涂湿地较丰富的AM真菌多样性可能与该湿地较良好的理化性质有关。     

植菌昆虫与其共生真菌协同进化分子机制

昆虫菌业（fungiculture）是一种类似于人类种植业的昆虫种植体系,包括种植、耕作、收获和营养依赖4个过程,可分为高级的社会性昆虫如切叶蚂蚁、白蚁等和低级的非社会性昆虫如食菌小蠹虫、卷叶象甲、蜥蜴甲虫、树蜂等,它们均能种植并取食真菌。近年来随着组学及微生物组技术的发展,植菌昆虫与其共生真菌协同进化的分子机制研究方面取得了重要进展。系统发育分析阐明了植菌昆虫的起源与进化历程,并显示出与共生真菌系统发育的一致性;共生真菌细胞核数量也从双核增加到最多17个核,而染色体倍型也从单倍体增加为二倍体甚至多倍体;组学分析则揭示了植菌昆虫与其共生真菌在精氨酸、碳水化合物、木质素及几丁质合成或降解等方面显示出了高度的协同进化。本文系统综述了植菌昆虫及其共生真菌的系统进化、核进化及基因组进化进展,并探讨这种协同进化机制的生物学意义。     

Strangler unmasked: Parasitism of Cystoderma amianthinum by Squamanita paradoxa and S. pearsonii

The mushroom-forming genus Squamanita comprises 10 described species, all parasitic on basidiomes of other members of the order Agaricales, including members of the genera Cystoderma, Galerina, Inocybe and Hebeloma. Here we report an anatomical investigation of the stipitate “mycocecidium’ (=fungus gall) formed on the basidiome of Cystoderma amianthinum (“powdercap”) by S. paradoxa (“powdercap strangler”), alongside the development of taxon-specific-PCR primer to localise the presence of S. paradoxa/C. amianthinum mycelia within mycocecidia, in associated plant tissues and apparently healthy host basidiomes. Dissection of fungarium samples also confirmed these findings, whilst ITS barcode sequencing of all available samples held at the RBG Kew and Edinburgh fungaria did not reveal any variation in ITS sequences within UK populations of S. paradoxa or the closely related S. pearsonii. The absence of any ¹³C or ¹⁵N isotopic differences between C. amianthinum and S. paradoxa suggests that S. paradoxa is nutritionally dependent on its host. The status of C. amianthinum as host of S. pearsonii is also confirmed.     

Under pressure from above: Overgrazing decreases mycorrhizal colonization of both preferred and unpreferred grasses in the Patagonian steppe

Arbuscular mycorrhizal fungi (AMF) are related to plant community dynamics and ecosystem functioning. Overgrazing can negatively affect plant performance, and consequently unbalance the association with AMF. We studied the grazing effect on AMF colonization for preferred (Bromus pictus and Poa ligularis) and unpreferred grasses (Pappostipa speciosa and Pappostipa humilis) by sheep in the Patagonian steppe. For each species, AMF colonization in ungrazed, moderate and intense grazing sites was quantified. In ungrazed areas, B. pictus showed the highest extent of AMF colonization. Mycorrhizal colonization was higher during the active season, and largely reduced by intense grazing conditions. The decrease of AMF colonization was maximal for the most preferred species, but also significant for the unpreferred species. Our results suggest that overgrazing could reduce mycorrhizal benefits for the plant by reduction of AMF colonization, which can be a good indicator of ecosystem functioning, eventually revealing an increasing degree of environmental degradation.     

Heterocyclic lactam derivatives containing piperonyl moiety as potential antifungal agents

To study the novel functionalized heterocyclic molecules with highly potential biological activity, two series of heterocyclic lactam derivatives containing the piperonyl moiety were designed and synthesized. The newly obtained compounds have been identified on the basis of analytical spectral data, including ¹H NMR, ¹³C NMR, and ESI-MS. The target compounds were evaluated for their potential antifungal activities in vitro against twelve species of the plant pathogen fungi (Sclerotinia sclerotiorum, Rhizoctonia solani, Rap Sclerotinia stemrot, Fusarium graminearum, Phomopsis adianticola, Pestallozzia theae, Pestalotiopsis guepinii, Alternaria tenuis Nees, Monilinia fructicola, Colletotrichum gloeosporioides, Phytophthora capsici, Magnaporthe oryzae). Preliminary bioassays suggested that all prepared compounds I1–14 displayed broad-spectrum and moderate antifungal activities compared with the positive control hymexazol, especially for Sclerotinia sclerotiorum, Rap Sclerotinia stemrot, and Monilinia fructicola. In particular, the inhibition rate of compound I9 exhibited good inhibition activity reached 95.16% against Sclerotinia sclerotiorum, and compounds I5, I12 against Phytophthora capsici were 93.44%, 91.25%. Further studies revealed that compounds I5 (IC₅₀ = 19.13 µM) and I12 (IC₅₀ = 9.12 µM) exhibited obviously antifungal activities against Phytophthora capsici, which were better than that of commercial agricultural fungicide hymexazol (IC₅₀ = 325.45 µM). Therefore, these target compounds could be further studied and explored as a lead skeleton for discovery of novel antifungal agents.     

Soil microbiome mediates positive plant diversity‐productivity relationships in late successional grassland species

Which processes drive the productivity benefits of biodiversity remain a critical, but unanswered question in ecology. We tested whether the soil microbiome mediates the diversity‐productivity relationships among late successional plant species. We found that productivity increased with plant richness in diverse soil communities, but not with low‐diversity mixtures of arbuscular mycorrhizal fungi or in pasteurised soils. Diversity‐interaction modelling revealed that pairwise interactions among species best explained the positive diversity‐productivity relationships, and that transgressive overyielding resulting from positive complementarity was only observed with the late successional soil microbiome, which was both the most diverse and exhibited the strongest community differentiation among plant species. We found evidence that both dilution/suppression from host‐specific pathogens and microbiome‐mediated resource partitioning contributed to positive diversity‐productivity relationships and overyielding. Our results suggest that re‐establishment of a diverse, late successional soil microbiome may be critical to the restoration of the functional benefits of plant diversity following anthropogenic disturbance.     

Unravelling the interactions of the environmental host Acanthamoeba castellanii with fungi through the recognition by mannose‐binding proteins

Free‐living amoebae (FLAs) are major reservoirs for a variety of bacteria, viruses, and fungi. The most studied mycophagic FLA, Acanthamoeba castellanii (Ac), is a potential environmental host for endemic fungal pathogens such as Cryptococcus spp., Histoplasma capsulatum, Blastomyces dermatitides, and Sporothrix schenckii. However, the mechanisms involved in this interaction are poorly understood. The aim of this work was to characterize the molecular instances that enable Ac to interact with and ingest fungal pathogens, a process that could lead to selection and maintenance of possible virulence factors. The interaction of Ac with a variety of fungal pathogens was analysed in a multifactorial evaluation that included the role of multiplicity of infection over time. Fungal binding to Ac surface by living image consisted of a quick process, and fungal initial extrusion (vomocytosis) was detected from 15 to 80 min depending on the organism. When these fungi were cocultured with the amoeba, only Candida albicans and Cryptococcus neoformans were able to grow, whereas Paracoccidioides brasiliensis and Sporothrix brasiliensis displayed unchanged viability. Yeasts of H. capsulatum and Saccharomyces cerevisiae were rapidly killed by Ac; however, some cells remained viable after 48 hr. To evaluate changes in fungal virulence upon cocultivation with Ac, recovered yeasts were used to infect Galleria mellonella, and in all instances, they killed the larvae faster than control yeasts. Surface biotinylated extracts of Ac exhibited intense fungal binding by FACS and fluorescence microscopy. Binding was also intense to mannose, and mass spectrometry identified Ac proteins with affinity to fungal surfaces including two putative transmembrane mannose‐binding proteins (MBP, L8WXW7 and MBP1, Q6J288). Consistent with interactions with such mannose‐binding proteins, Ac–fungi interactions were inhibited by mannose. These MBPs may be involved in fungal recognition by amoeba and promotes interactions that allow the emergence and maintenance of fungal virulence for animals.     

Diversity and distribution of hidden cultivable fungi associated with marine animals of Antarctica

In the present study, we surveyed the distribution and diversity of fungal assemblages associated with 10 species of marine animals from Antarctica. The collections yielded 83 taxa from 27 distinct genera, which were identified using molecular biology methods. The most abundant taxa were Cladosporium sp. 1, Debaryomyces hansenii, Glaciozyma martinii, Metschnikowia australis, Pseudogymnoascus destructans, Thelebolus cf. globosus, Pseudogymnoascus pannorum, Tolypocladium tundrense, Metschnikowia australis, and different Penicillium species. The diversity, richness, and dominance of fungal assemblages ranged among the host; however, in general, the fungal community, which was composed of endemic and cold-adapted cosmopolitan taxa distributed across the different sites of Antarctic Peninsula, displayed high diversity, richness, and dominance indices. Our results contribute to knowledge about fungal diversity in the marine environment across the Antarctic Peninsula and their phylogenetic relationships with species that occur in other cold, temperate, and tropical regions of the World. Additionally, despite their extreme habitats, marine Antarctic animals shelter cryptic and complex fungal assemblages represented by endemic and cosmopolitan cold-adapted taxa, which may represent interesting models to study different symbiotic associations between fungi and their animal hosts in the extreme conditions of Antarctica.