Propagation strategy of ammonia fungi

Ammonia fungi invade forest floors immediately after a enrichment disturbance by a large input of ammonium-nitrogen. Latent form(s) of the ammonia fungi are spores and/or mycelium fragments. Ammonia fungi are characterized by their rapid germination stimulated by the presence of ammonium-nitrogen under neutral to weakly alkaline conditions. Each ammonia fungus establishes its territory during suppressed combative abilities of other microbes following ammonium-nitrogen disturbance. Earlyphase ammonia fungi (EP fungi) quickly sporulate before nonammonia fungi colonize with the declining of ammonium-nitrogen concentration associated with descending pH. Ectomycorrhizal species of late-phase ammonia fungi (LP fungi) escape from the L-F horizon as a result of interactions between EP fungi and form mycorrhizae in the H-A horizon when other fungal activities are suppressed by the ammonium-nitrogen disturbance. Ectomycorrhizal ammonia fungi initially use ammonium-nitrogen when the pH rises because of the ammonium-nitrogen disturbance and then gradually utilize both ammonium- and nitratenitrogen when the effects of the ammonium-nitrogen disturbance weaken. Early-stage EP fungi are ruderal stress-tolerant strategists whereas late-stage EP fungi are combative ruderal strategists. LP fungi are combative strategists from the standpoint of the interactions between other ammonia fungi. This classification is based on differences in their respective propagation strategies.     

Ambrosia fungi in the insect-fungi symbiosis in relation to cork oak decline

Ambrosia fungi live associated with beetles (Scolytidae and Platypodidae) in host trees and act as a food source for the insects. The symbiotic relation is important to the colonizing strategies of host trees by beetles. Ambrosia fungi are dimorphic: they grow as ambrosial form and as mycelium. The fungi are highly specialized, adapted to a specific beetle and to the biotope where they both live. In addition other fungi have been found such as tree pathogenic fungi that may play a role in insects host colonization success. Saprophytic fungi are also present in insects galleries. These may decompose cellulose and/or be antagonistic to other less beneficial fungi. This paper summarizes the importance of ambrosia fungi and the interaction with insects and hosts. The possibility of the transport of pathogenic fungi by Platypus cylindrus to cork oak thus contributing for its decline is discussed.     

食线虫真菌资源研究概况

食线虫真菌是指寄生、捕捉、定殖和毒害线虫的一类真菌,这类真菌是自然界中线虫种群控制的重要因子,也是动植物病害生物防治的重要研究材料,具有特殊的研究意义和经济价值。目前全世界共报道700余种食线虫真菌,包括捕食线虫真菌380余种,线虫内寄生真菌120余种,产毒真菌270余种和大量机会真菌。针对丰富的食线虫真菌资源,近年来世界各国尤其是中国科学家对其进行了广泛研究,在捕食线虫真菌资源的分类、系统进化、生态分布、有性无性联系等方面的研究取得了重要进展,在线虫内寄生真菌侵染宿主的方式及产毒真菌的次生代谢产物挖掘等方面也进行了广泛研究,文章综述了以上研究进展并简述了食线虫真菌资源的生物防治应用概况。     

Outcome of interspecific interactions among brown-rot and white-rot wood decay fungi

Abstract Interspecific mycelial interactions among brown-rot fungi resulted in either deadlock or replacement of one fungus by the other. Similarly, most of the brown-rot fungi deadlocked with some or all of the whitre-rot fungi tested, while a few were able to replace some of the white-rot fungi. The results indicate similarities in interspecific mycelial interactions among brown-rot fungi and between brown-rot and white-rot fungi. The results further suggest that some brown-rot fungi are capable of invading and occupying domains within white-rot fungal communities in decaying wood.     

培菌白蚁与鸡枞菌研究进展

培菌白蚁起源于非洲,蚁巢内具有复杂的社会分工.培菌白蚁依靠独特的蚁巢结构维持内部稳态和气体循环.菌圃是白蚁培育鸡枞菌的场所.鸡枞菌隶属于担子菌亚门,但其传播方式和生活史具有区别于其它担子菌的特点.鸡枞菌协助白蚁进行植物纤维的消化,白蚁则为鸡枞菌提供合适的生长环境,并控制鸡枞菌的遗传结构.培菌白蚁和鸡枞菌形成紧密的共生关...     

Interactions between wood-inhabiting fungi and termites: a meta-analytical review

The foraging behavior and survivorship of termites are modified by the presence of wood-inhabiting fungi. Nonetheless, it is not clear if these interactions are beneficial, negative, or neutral for termites. We conducted a meta-analytical review to determine if the presence of wood-inhabiting fungi affects the foraging behavior and survivorship of termites. Overall, the presence of wood-inhabiting fungi in a resource used by termites was positive, increasing resource consumption by 120%, and aggregation behavior by 81%. The presence of fungi also increased termite trail-following by approximately 200% and increased survival by 136%. The results varied, however, according to the type of fungi evaluated. Decay fungi and sap-stain fungi elicited positive responses in termites, whereas molds did not affect the consumption of cellulose by termites. Amongst the decay fungi group, white-rot fungi caused the strongest and most positive response in all termite behaviors evaluated, although brown-rot fungi is known to be preferred by termites. The results of our study, therefore, suggest that wood-inhabiting fungi are potential facilitators of the foraging behavior and survivorship of termites. These results have great implications for termite biocontrol, as well as for knowledge of the ecological aspects of termite–fungi interactions.     

内生真菌侵染对黑麦草种子萌发、幼苗生长及渗透胁迫抗性的影响

以含有内生真菌的黑麦草(Lolium perenne L.)种子为材料,采用4 ℃冰箱内和20 ℃培养箱内保存18个月的方式分别构建内生真菌侵染（EI）和内生真菌非侵染（EF）的黑麦草种群,通过比较EI和EF种群在正常条件下（对照）和渗透胁迫条件下种子发芽、幼苗生长等方面的差异,探讨内生真菌对其宿主植物的直接和间接影响。结果表明：在对照和胁迫条件下,EI种子的发芽势及发芽率均明显高于EF种子,而在重度胁迫下EI植株的叶延伸速率、根系总长度高于EF植株。内生真菌对宿主植物分蘖数和生物量的变化没有促进作用,但     

Mycorrhizal fungi of Vanilla: diversity, specificity and effects on seed germination and plant growth

Mycorrhizal fungi are essential for the germination of orchid seeds. However, the specificity of orchids for their mycorrhizal fungi and the effects of the fungi on orchid growth are controversial. Mycorrhizal fungi have been studied in some temperate and tropical, epiphytic orchids, but the symbionts of tropical, terrestrial orchids are still unknown. Here we study diversity, specificity and function of mycorrhizal fungi in Vanilla, a pantropical genus that is both terrestrial and epiphytic. Mycorrhizal roots were collected from four Vanilla species in Puerto Rico, Costa Rica and Cuba. Cultured and uncultured mycorrhizal fungi were identified by sequencing the internal transcribed spacer region of nuclear rDNA (nrITS) and part of the mitochondrial ribosomal large subunit (mtLSU), and by counting number of nuclei in hyphae. Vanilla spp. were associated with a wide range of mycorrhizal fungi: Ceratobasidium, Thanatephorus and Tulasnella. Related fungi were found in different species of Vanilla, although at different relative frequencies. Ceratobasidium was more common in roots in soil and Tulasnella was more common in roots on tree bark, but several clades of fungi included strains from both substrates. Relative frequencies of genera of mycorrhizal fungi differed significantly between cultured fungi and those detected by direct amplification. Ceratobasidium and Tulasnella were tested for effects on seed germination of Vanilla and effects on growth of Vanilla and Dendrobium plants. We found significant differences among fungi in effects on seed germination and plant growth. Effects of mycorrhizal fungi on Vanilla and Dendrobium were similar: a clade of Ceratobasidium had a consistently positive effect on plant growth and seed germination. This clade has potential use in germination and propagation of orchids. Results confirmed that a single orchid species can be associated with several mycorrhizal fungi with different functional consequences for the plant.     

Nitrogen content, amino acid composition and digestibility of fungi from a nutritional perspective in animal mycophagy

Fungi comprise a major part of the diet of many animals. Even so, the nutritional value of fungi has been much debated, with some arguing that fungi are nutritionally poor. However, the chemical composition of fungi and of the biology of the animals that eat them are not well understood, particularly in reference to amino acid (AA) composition of fungi and digestibility of fungal protein. We analysed fibre, total nitrogen (N), available N, and AA contents and measured in vitro digestibility of a wide range of epigeous and hypogeous fungi collected in Australia and the USA to test three hypotheses: (i) fungi are nutritionally poor because they contain few nutrients or are otherwise of low digestibility, (ii) fungi vary substantially in their nutritional composition; and (iii) animals can counter this variable quality by eating diverse taxa. Resultant data indicate many fungi are a reasonable source of AAs and digestible nitrogen. However, they vary highly between species in AA content, and the protein has a poor balance of digestible AAs. This helps explain why many mycophagous animals eat a wide array of fungi and often have digestive strategies to cope with fungi, such as foregut fermentation. Another common strategy is to supplement the diet with high quality protein, such as insect protein. Accordingly, evaluating nutritional value of fungi requires consideration of physiology of the animal species and their whole diet.     

Variation in mycorrhizal growth response influences competitive interactions and mechanisms of plant species coexistence

Plant species vary in their growth response to arbuscular mycorrhizal (AM) fungi, with responses ranging from negative to positive. Differences in response to AM fungi may affect competition between plant species, influencing their ability to coexist. We hypothesized that positively responding species, whose growth is stimulated by AM fungi, will experience stronger intraspecific competition and weaker interspecific competition in soil containing AM fungi, while neutrally or negatively responding species should experience weaker intraspecific and stronger interspecific competition. We grew Plantago lanceolata, which responds positively to AM fungi, and Bromus inermis, which responds negatively to AM fungi, in an additive response surface competition experiment that varied the total density and relative frequency of each species. Plants were grown in sterilized background soil that had been inoculated with whole soil biota, which includes AM fungi, or a microbial wash, that contained other soil microbes but no AM fungi, or in sterilized soil that contained no biota. The positively responding P. lanceolata was more strongly limited by intraspecific than interspecific competition when AM fungi were present. By contrast, the presence of AM fungi decreased the strength of intraspecific competition experienced by the negatively responding B. inermis. Because AM fungi are almost always present in soil, strong intraspecific competition in positively responding species would prevent them from outcompeting species that respond neutrally or negatively to AM fungi. The potential for increased intraspecific competition to offset growth benefits of AM fungi could, therefore, be a stabilizing mechanism that promotes coexistence among plant species.     

食（药）用真菌比较基因组分析揭示其生态特性

食（药）用真菌可以产生多种酶系家族来降解环境中的木质纤维素,从而获得营养或与植物共生或寄生。通过注释和比较不同营养模式的食（药）用真菌中降解木质纤维素的酶类,有利于我们更好地认识食（药）用真菌的生活模式,并进一步改善培养条件。本文系统地研究了46个食（药）用真菌和3个降解木质纤维素模式真菌的基因组,根据预测蛋白质组解析了糖苷水解酶（glycoside hydrolases,GHs）、糖基转移酶（glycosyltransferases,GTs）、多糖裂解酶（polysaccharide lyases,PLs）、碳水化合物酯酶（carbohydrate esterases,CEs）、碳水化合物结合模块（carbohydrate-binding modules,CBMs）以及附属活力酶（auxiliary activities,AAs）和细胞色素P450（cytochromes P450）的种类分布。比较基因组学结果显示,食（药）用真菌中降解木质纤维素相关酶系家族的数量和种类差别很大,同时酶系家族的多样性与食（药）用真菌的生态类型也有一定的相关性。一般情况下,腐生营养真菌比共生营养真菌中降解木质纤维素酶类更多,而腐生营养中的白腐真菌和草腐真菌的酶系比褐腐真菌多。     

Biology of gut anaerobic fungi

The obligately anaerobic nature of the gut indigenous fungi distinguishes them from other fungi. They are distributed widely in large herbivores, both in the foregut of ruminant-like animals and in the hindgut of hindgut fermenters. Comparative studies indicate that a capacious organ of fermentative digestion is required for their development. These fungi have been assigned to the Neocallimasticaceae, within the chytridiomycete order Spizellomycetales. The anaerobic fungi of domestic ruminants have been studied most extensively. Plant material entering the rumen is rapidly colonized by zoospores that attach and develop into thalli. The anaerobic rumen fungi have been shown to produce active cellulases and xylanases and specifically colonise and grow on plant vascular tissues. Large populations of anaerobic fungi colonise plant fragment in the rumens of cattle and sheep on high-fibre diets. The fungi actively ferment cellulose which results in formation of a mixture of products including acetate, lactate, ethanol, formate, succinate, CO2 and H2. The properties of the anaerobic fungi together with the extent of their populations on plant fragments in animals on high-fibre diets indicates a significant role for the fungi in fibre digestion.     

水分胁迫下内生真菌感染对黑麦草叶内游离脯氨酸和脱落酸含量的影响

以黑麦草为实验对象,研究了干旱胁迫条件下内生真菌感染对植株叶片含水量和叶内游离脯氨酸含量的影响,同时对渗透胁迫条件下植株叶内ABA含量的变化进行了分析。结果表明：①内生真菌的感染有助于使叶片保持较高的含水量;②在两种形式的水分胁迫下,。前期至中期高感染种群的叶片游离脯氨酸含量低于感染种群,而在末期则有高出低感染种群的趋势;③内生真菌感染对黑麦草叶内ABA累积的正效应只发生在轻度渗透胁迫下的较短时间范围内。     

内生真菌侵染对黑麦草种子萌发、幼苗生长及渗透胁迫抗性的影响

 以含有内生真菌的黑麦草(Lolium perenne L.)种子为材料,采用4 ℃冰箱内和20 ℃培养箱内保存18个月的方式分别构建内生真菌侵染（EI）和内生真菌非侵染（EF）的黑麦草种群,通过比较EI和EF种群在正常条件下（对照）和渗透胁迫条件下种子发芽、幼苗生长等方面的差异,探讨内生真菌对其宿主植物的直接和间接影响。结果表明：在对照和胁迫条件下,EI种子的发芽势及发芽率均明显高于EF种子,而在重度胁迫下EI植株的叶延伸速率、根系总长度高于EF植株。内生真菌对宿主植物分蘖数和生物量的变化没有促进作用,但     

Genetic variation of symbiotic fungi cultivated by the macrotermitine termite Odontotermes formosanus (Isoptera: Termitidae) in the Ryukyu Archipelago

Fungus-growing termites have a mutualistic relationship with their cultivated fungi. To improve understanding of genetic aspects of this relationship, we examined molecular markers in the fungus-growing termite Odontotermes formosanus and its fungi Termitomyces spp. from the Ryukyu Archipelago. Based on the polymorphic band patterns obtained from arbitrarily primed polymerase chain reaction methods, we constructed cladograms for related colonies of the termites and fungi. The resulting trees indicated that the termites display little genetic variation among the colonies, while the symbiotic fungi consist of two major genetic types. In addition, molecular phylogenetic trees of the symbiotic fungi based on internal transcribed spacer and 18S rDNA suggested that these two types of fungi are different species. We also demonstrated that the fungi comprising the fruiting bodies and fungus combs are identical, and that fungus combs are probably a monoculture within a single termite colony. Our results indicate that horizontal transmission of symbiotic fungi among termite colonies occurred during the evolutionary history of this symbiosis.     

The screening and selection of inoculant arbuscular-mycorrhizal and ectomycorrhizal fungi

The initiation of a programme of screening and selection of arbuscular-mycorrhizal fungi (AM fungi) and ectomycorrhizal fungi (ECM fungi) for use as inoculant fungi in agriculture, horticulture of forestry will depend on whether inoculation is more appropriate as a management option than manipulation of the indigenous mycorrhizal populations. The greatest immediate potential for the successful use of mycorrhizal inoculants will be in soils and growth media where phosphorus (P) limits plant growth and where the indigenous mycorrhizal fungi are either ineffective at increasing P uptake by the plant or their numbers have been drastically reduced by human influence or natural disturbance. In recent investigations, however, additional benefits to the plant following colonization of roots by effective AM or ECM fungi have been demonstrated. These additional benefits of an effective mycorrhizal association have necessitated a re-evaluation of the optimum screening procedures for isolates of AM and ECM fungi. Both current methodologies and suggestions for alternative approaches to the screening of AM and ECM fungi are discussed in this paper. The problems inherent in choosing suitable experimental conditions to compare different isolates at the screening stage are also addressed. The review also stresses the importance of continued monitoring of introduced mycorrhizal fungi to learn more about their longer-term ecological role, particularly within reforestation or revegetation studies.     

红树林内生真菌研究进展

红树林作为一种特殊的植物群落具有丰富的内生真菌资源,目前已分离鉴定的红树林真菌超过200种,成为海洋真菌的第二大类群,已报道的红树林内生真菌主要类群是链格孢霉(Alternaria)、曲霉(Aspergillus)、芽枝霉(Cladosporium)、炭疽菌(Colletotrichum)、镰孢霉(Fusarium)、拟青霉(Paecilomyces)、拟盘多毛孢(Pestalotiopsis)、青霉(Penicillium)、茎点霉(Phoma)、拟茎点霉(Phomopsis)、叶点霉(Phyllosticta)和木霉(Trichoderma)等.大部分红树林内生真菌具有较宽的宿主范围,极少数只有单一的宿主,不同红树林植物的内生真菌区系及优势种群有很大差异.红树林内生真菌的定殖因宿主植物不同部位、植株的年龄及季节和环境的变化明显不同.红树林内生真菌能产生多种代谢产物,具有抗菌、抗肿瘤等药用价值.红树林植物内生真菌的研究和开发具有重要意义.本文综述了红树林内生真菌的生物多样性及其分布、生物学功能和次生代谢产物等方面的研究进展.     

贵州栽培笃斯越橘DSE真菌、AM真菌与ERM真菌空间分布研究

为探明贵州省栽培笃斯越橘根系深色有隔内生真菌（dark septate endophytes,DSE）、丛枝菌根（arbuscular mycorrhiza,AM）真菌与欧石南菌根（ericoid mycorrhiza,ERM）真菌的定殖及地理分布情况,揭示共生真菌在栽培笃斯越橘生长中的地位,本研究在贵州省笃斯越橘主栽区麻江县、凤岗县和高坡乡分别选取主栽品种圆蓝、粉蓝、奥尼尔和莱格西的根样及根围土样,观测不同地区不同品种根样DSE真菌、AM真菌和ERM真菌的定殖结构和定殖率,并测定土样土壤理化性质,分析不同真菌与土壤因子相关性。结果表明,3个地区的4个笃斯越橘品种均有DSE真菌、AM真菌和ERM真菌定殖,栽培笃斯越橘能与3类真菌形成共生关系,平均定殖率分别为61.11%、25.55%和22.50%。DSE真菌定殖率：高坡（62.50%）>麻江（61.66%）>凤岗（59.16%）;AM真菌定殖率：凤岗（34.14%）>麻江（25.83%）>高坡（16.66%）;ERM真菌定殖率：高坡（35.00%）>凤岗（20.00%）>麻江（12.5%）。相关性分析表明,DSE真菌中的菌丝与微菌核的定殖率呈负相关,AM真菌的总定殖率及定殖强度与微菌核的定殖率呈极显著正相关,与DSE真菌菌丝的定殖率呈负相关。ERM真菌总定殖率与DSE真菌菌丝的定殖率及AM真菌定殖强度呈极显著正相关,与DSE真菌总定殖率呈显著正相关。土壤有效磷与DSE真菌和ERM真菌总定殖率呈显著正相关,与AM真菌定殖率呈显著负相关。土壤铵态氮与DSE真菌中微菌核结构定殖率及AM真菌定殖率呈极显著正相关,与ERM真菌定殖率呈极显著负相关。土壤pH值与DSE定殖强度呈显著负相关,与ERM定殖强度呈极显著正相关。本研究分析比较贵州省3个笃斯越橘种植基地不同品种栽培笃斯越橘DSE真菌、AM真菌和ERM真菌的定殖及其与土壤理化性质之间的相关性,为贵州省栽培笃斯越橘的管理和发展提供技术基础和理论依据。     

Role of fungi in freshwater ecosystems

There are more than 600 species of freshwater fungi with a greater number known from temperate, as compared to tropical, regions. Three main groups can be considered which include Ingoldian fungi, aquatic ascomycetes and non-Ingoldian hyphomycetes, chytrids and, oomycetes. The fungi occurring in lentic habitats mostly differ from those occurring in lotic habitats. Although there is no comprehensive work dealing with the biogeography of all groups of freshwater fungi, their distribution probably follows that of Ingoldian fungi, which are either cosmopolitan, restricted to pantemperate or pantropical regions, or in a few cases, have a restricted distribution. Freshwater fungi are thought to have evolved from terrestrial ancestors. Many species are clearly adapted to life in freshwater as their propagules have specialised aquatic dispersal abilities. Freshwater fungi are involved in the decay of wood and leafy material and also cause diseases of plants and animals. These areas are briefly reviewed. Gaps in our knowledge of freshwater fungi are discussed and areas in need of research are suggested.