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。     

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.     

Chemical synthesis,expression and mutagenesis of a gene encoding β-cryptogein,an elicitin produced by Phytophthora cryptogea

Elicitins are 10 kDa holoproteins secreted by Phytophthora fungi, that elicit an incompatible hypersensitive reaction, leading to resistance against fungal and bacterial plant pathogens. Comparison of primary sequences of -elicitins and -elicitins indicated several potential necrotic activity-determining residues. All of the highly necrotic -elicitins have a hydrophilic residue (usually lysine) at position 13, whereas in the less necrotic -elicitins this residue is replaced by a valine. Here, we report the synthesis and expression of a gene encoding a highly necrotic elicitin, -cryptogein, and we show that the substitution of Lys-13 of this recombinant protein by a valine leads to a drastic alteration to the necrotic activity of the recombinant protein.     

Effects of fungal pretreatment and steam explosion pretreatment on enzymatic saccharification of plant biomass

The effects of consecutive treatments by a lignin-degrading fungus Phanerochaete chrysosporium and by steam explosion for the enzymatic saccharification of plant biomass were studied experimentally, and the optimal operational conditions for obtaining the maximum saccharification were evaluated. Beech wood-meal was treated by the fungus for 98 days and then by high steam temperatures of 170-230 degrees C with steaming times of 0-10 min. The treatment of the wood-meal by fungus prior to steam explosion enhanced the saccharification of wood-meal. The treated wood-meal was separated into holo-cellulose, water soluble material, methanol soluble lignin, and Klason lignin. The saccharification decreased linearly with the increase in the amount of Klason lignin. It was estimated by the equation for the saccharification of exploded wood-meal expressed as a function of steam temperature and steaming time that the maximum saccharification of wood-meal was obtained by consecutive treatments such as fungal treatment for 28 days and then steam explosion at a steam temperature of 215 degrees C and a steaming time of 6.5 min. (c) 1995 John Wiley & Sons, Inc.     

Factors related to diversity of decomposer fungi in tropical forests

Recent studies suggest that host-preferences are common among certain groups of tropical fungal decomposers but rare in others, and sometimes occur where we least expect them. Host preferences among microfungi and ascomycetes that decompose leaf litter are common but usually involve differences in relative frequencies more than presence/absence, so their diversity may be loosely correlated with species richness of host trees. Strong host-specificity appears to be rare among wood decomposer fungi, whereas characteristics of their substrata and habitat are very important for this group. Anthropogenic disturbance predisposed a tropical forest to subsequent hurricane damage, and the resulting direct and indirect effects on host diversity and habitat heterogeneity were reflected in the decomposer fungal community more than sixty years after the original disturbance. While species richness of dictyostelid slime molds and functional diversity of their bacterial prey increased with disturbance, the more diverse microfungi and ascomycetes were apparently negatively affected by disturbance.     

Tolerance to the fungal pathogen Rhizoctonia solani AG4 of transgenic tobacco expressing the maize ribosome-inactivating protein b-32

The maize b-32 protein is a functional ribosome-inactivating protein (RIP), inhibiting in vitro translation in the cell-free reticulocyte-derived system and having specific N-glycosidase activity on 28S rRNA. Previous results indicated that opaque-2 (o2) mutant kernels, lacking b-32, show an increased susceptibility to fungal attack and insect feeding and that ectopic expression in plants of a barley and a pokeweed RIP leads to increased tolerance to fungal and viral infection. This prompted us to test whether b-32 might functi on as a protectant against pathogens. The b32.66 cDNA clone under the control of the potato wun1 gene promoter was introduced into tobacco by Agrobacterium tumefaciens-mediated transformation. Out of 23 kanamycin resistant regenerated shoots, 16 contained a PCR fragment of the corrrect size spanning the boundary between the promoter used and the coding region of the b-32 gene. Eight independently transformed tobacco lines were randomly chosen for protein analysis: all of them expressed b-32 protein. The data presented indicate that transgenic tobacco plants expressing b-32 show an increased tolerance against infection by the soil-borne fungal pathogen Rhizoctonia solani Kuhn     

A survey of black dot and other fungal tuber blemishing diseases in British potato crops at harvest

Black dot and other fungal blemishing diseases were assessed on tubers from crops in eastern England in 1987 and 1988, and in 1989 and 1990 from crops throughout Great Britain. Black dot was found on tubers in crops from all areas of the country, and was most common in those from eastern and southern England. The disease was scarce on most Scottish crops, but occasionally some were severely affected. In 1988 there was no consistent relationship between the amounts of disease on the seed and subsequent ware crop. On average, the disease was more prevalent in irrigated crops and where the interval between successive potato crops was short. In 1990 treating seed tubers with fungicide had no effect on subsequent levels of disease. Few crops were unaffected by silver scurf, and it was most common in crops from southern and eastern England. In the national survey common scab was the most prevalent disease, black scurf was less common and skin spot and powdery scab uncommon except in some Scottish crops.