High diversity and low specificity of fungi associated with seedless epiphytic plants

Epiphytes, which grow on other plants for support, make up a large portion of Earth's plant diversity. Like other plants, their surfaces and interiors are colonized by diverse assemblages of fungi that can benefit their hosts by increasing tolerance for abiotic stressors and resistance to disease or harm them as pathogens. Fungal communities associated with epiphytic plants and the processes that structure these communities are poorly known. To address this, we sampled seven epiphytic seedless plant taxa in a Costa Rican rainforest and examined the effects of host identity and microhabitat on external and endophytic fungal communities. We found low host specificity for both external and endophytic fungi and weak differentiation between epiphytic and neighboring epilithic plant hosts. High turnover in fungi within and between hosts and habitats reveals that epiphytic plant-associated fungal communities are highly diverse and suggests that they are structured by stochastic processes.     

非编码小RNA对细菌毒力及耐药性的调控作用研究进展

近年来的研究发现,细菌非编码小RNA (small non-coding RNA, sRNA)对其不同生理进程起到了重要的调控作用。随着大量sRNA被发现并鉴定,细菌sRNA的功能被逐步阐明,其可在转录后水平广泛调控细菌的生理代谢、毒力及耐药性等。本文综述了sRNA对细菌毒力和耐药性调控作用的研究进展,对揭示细菌转录后水平毒力及耐药性调控机制具有一定意义。     

Chemical Profile and Biological Activities of Fungal Strains Isolated from Piper nigrum Roots: Experimental and Computational Approaches

The current report describes the chemical investigation and biological activity of extracts produced by three fungal strains Fusarium oxysporum, Penicillium simplicissimum, and Fusarium proliferatum isolated from the roots of Piper nigrum L. growing in Vietnam. These fungi were namely determined by morphological and DNA analyses. GC/MS identification revealed that the EtOAc extracts of these fungi were associated with the presence of saturated and unsaturated fatty acids. These EtOAc extracts showed cytotoxicity towards cancer cell lines HepG2, inhibited various microbacterial organisms, especially fungus Aspergillus niger and yeast Candida albicans (the MIC values of 50–100 μg/mL). In α-glucosidase inhibitory assay, they induced the IC₅₀ values of 1.00-2.53 μg/mL were better than positive control acarbose (169.80 μg/mL). The EtOAc extract of F. oxysporum also showed strong anti-inflammatory activity against NO production and PGE-2 level. Four major compounds linoleic acid (37.346 %), oleic acid (27.520 %), palmitic acid (25.547 %), and stearic acid (7.030 %) from the EtOAc extract of F. oxysporum were selective in molecular docking study, by which linoleic and oleic acids showed higher binding affinity towards α-glucosidase than palmitic and stearic acids. In subsequent docking assay with inducible nitric oxide synthase (iNOS), palmitic acid, oleic acid and linoleic acid could be moderate inhibitors.     

Soil amendment with biochar and manure alters wood stake decomposition and fungal community composition

Biochar and manure can be used for sustainable land management. However, little is known about how soil amendments might affect surface and belowground microbial processes and subsequent wood decomposition. In a split-split-split plot design, we amended soil with two rates of manure (whole plot; 0 and 9 Mg ha⁻¹) and biochar (split plot; 0 and 10 Mg ha⁻¹). Wood stakes of three species (hybrid poplar, triploid Populus tomentosa Carr.; aspen, Populus tremuloides Michx.; and pine, Pinus taeda L.) were placed in two positions (horizontally on the soil surface, and inserted vertically in the mineral soil), which served as a substrate for fungal growth. In 3 years, the decomposition rate (density loss), moisture content, and fungal community (via high-throughput sequencing methods) of stakes were evaluated. Results indicated that biochar and/or manure increased the wood stake decomposition rates, moisture content, and operational taxonomic unit abundance. However, the richness and diversity of fungi were dependent on wood stake position (surface > mineral), species (pine > the two Populus), and sample dates. This study highlights that soil amendment with biochar and/or manure can alter the fungal community, which in turn can enhance an important soil process (i.e., decomposition).     

中国菌物分类学和多样性研究的历史与现状概况

我国菌物分类学研究始于20世纪初,经过百余年的不断探索和发展,取得了丰硕的成果,并逐渐走进世界前列。本研究通过对世界菌物名称信息库Fungal Names进行数据统计,对发现自中国的菌物新物种和中国学者发表菌物新分类单元等数据开展分析,从中揭示中国菌物分类学的历史和发展趋势。过去,一共有2 214位中国学者参与发表了15 626个菌物新分类单元,包括 3个新纲、27个新目及亚目、117个新科及亚科、769个新属及亚属、11 100个新种、322个新种下单元和3 288个新组合。在全球已知的菌物物种中,自中国发现的新物种有10 233种,隶属于 3界13门44纲174目572科2 379属,占全球已知物种多样性的6.84%,居世界第二位。地理分布上,我国西南地区(云南、四川、贵州、西藏)和低纬度的热带、亚热带地区(中国台湾、广东)发现的新物种最多。根据每年发现的新分类单元数量趋势和命名作者的构成,可将中国菌物分类学的发展历史分为五个阶段：外人在华采菌及研究(1750s-1929)、中国菌物分类学起步(1930-1949)、新中国菌物分类学早期发展(1950-1977)、全国性菌物标本采集与研究(1978-2010)、走进世界前列(2011至今)。本研究对每个发展时期的分类学概况和重要历史事件进行了总结和回顾,通过上述综述性研究,有助于系统地了解中国菌物分类学不同阶段的发展趋势和研究概况,为学科当下和未来的发展提供参考。     

《中国真菌志》50年编研成果及展望

历经几代真菌人的艰苦奋斗,《中国真菌志》目前已出版65卷,其中子囊菌类有35卷、担子菌类26卷、接合菌类1卷、卵菌1卷、黏菌2卷;上述卷册记录923属9 228种及种下分类群。编研涉及大型和小型的类群、腐生菌、食药用菌、菌根真菌、作物和林木病原菌、捕食性真菌、虫生菌、菌生真菌以及毒菌等。编研过程中发现并发表了大量新分类群,丰富了对菌物物种多样性的认知。归纳已有成果,已立项卷册应加快编研和出版进度;资源调查与分类学研究需进一步加强,按分类群(专科、专属)继续开展编研工作,注重拟参编类群的前期研究积累;以下分类群值得在后续工作中予以关注：水霉目等部分卵菌、壶菌类、座囊菌纲部分类群、盘菌纲和锤舌菌纲中尚未参编的主要类群、伞菌纲中具有小型子实体的类群等。由于分类系统在不断更新和完善,已出版卷册中使用的部分名称和分类地位的处理需依据被大多数学者所公认的分类系统给予适时的订正。期待建设一支继往开来的菌物分类学研究队伍,不断取得令世人瞩目的编研成果,为我国菌物资源利用和物种保护提供科学依据。     

Characterization of New Highly Virulent German Isolates of Bremia lactucae and Efficiency of Resistance in Wild Lactuca spp. Germplasm

Four German isolates (FS1, SR2, SAW1 and DEG2) of Bremia lactucae originating from lettuce cultivars with R‐factors R18 and Dm6 + R36 were used for detailed characterization of virulence factors (v‐factors) and for the study of the resistance efficiency in wild Lactuca spp. germplasm. The highest complexity of v‐phenotype was recognized in isolate DEG2, which overcomes resistance in cv. Mariska (R18) and line CS‐RL (L. serriola × L. sativa, R18 + ?), until now known as resistant to all known races of B. lactucae in Europe. However, some sparse sporulation also occurred on cv. Titan (Dm6 + R36). The isolates SR2 and SAW1 overcome the resistance based on the gene R36, but are avirulent to R18. The v‐phenotype of SR2 is highly complex with the most important v‐factors being present except for v14 and v18. The isolate FS1 is the first in Germany originating from a cultivar with R18 (cv. Samourai). The search for efficient sources of resistance in 64 accessions of 11 wild Lactuca spp. and primitive forms of L. sativa showed broad variation in accession–isolate interactions. Expression of race‐specific resistance in wild Lactuca spp. (L. serriola, L. viminea, L. virosa) was recorded frequently. Lactuca indica and L. saligna could be considered as the most efficient sources of resistance against isolates FS1, SR2 and SAW1. The isolate DEG2 showed the highest level of virulence. On seedlings of L. saligna, which is considered as a most important source of resistance against B. lactucae, there was frequently recorded limited sporulation, however this response cannot be considered as a susceptible. Except for some L. saligna accessions (CGN 05310 and CGN 05315), the resistance to all studied isolates was only observed in one accession of L. serriola (PI 253467).     

The Influence of Genotype and Environment on the Physiological and Metabolic Diversity ofFusarium compactum

Talbot, N. J., Vincent, P., and Wildman, H. G. 1996. The influence of genotype and environment on the physiological and metabolic diversity ofFusarium compactum. Fungal Genetics and Biology20,254–267. Fungal species produce a large variety of secondary metabolites which are of considerable interest to the pharmaceutical industry. It is clear that the secondary metabolite production of a species varies significantly in strains from different geographic locations and from different habitats. The influence of genotype and environment on metabolite production is, however, poorly understood. In this study we examined the influence of genotypic variability, physiological variability, environmental location, and habitat on metabolite production byFusarium compactum.Isolates of the fungus from two geographic locations and two distinct habitat types were examined for growth on 95 different carbon sources, and genotypic variability was determined using RAPDs and rDNA–RFLP analysis. In a blind test secondary metabolite production was assessed using HPLC profiles of methanolic cell extracts. A number of correlations were observed between genotypic groupings, as determined using parsimony, and specific metabolite production. Similar correlations were also observed with physiological groups although genotypic analysis proved to be a more sensitive predictor of metabolite variability. The data suggest a complex relationship between environment, genotype, and metabolite production but highlight the use of genetic screening as a means of optimizing the chances of identifying a wide range of metabolites from a given species.