Stromatinia cryptomeriae sp. nov., the teleomorph ofGloeosporidina cryptomeriae causing twig blight of Japanese cedar

A new species,Stromatinia cryptomeriae, is described based on a specimen collected in Iwate Prefecture, Japan. It was found on fallen dead branches and twigs of Japanese cedar,Cryptomeria japonica. The morphology of isolates on potato-dextrose agar (PDA), which were obtained from single ascospores ofS. cryptomeriae, was identical withGloeosporidina cryptomeriae, the causal fungus of Japanese cedar twig blight. In an inoculation test using single ascospore isolates, many minute black spots (sclerotioid bodies; sclerotules) and acervuli ofG. cryptomeriae were formed on the necrotic lesions, which developed into typical symptoms of Japanese cedar twig blight. These results show thatStromatinia cryptomeriae is the teleomorph ofG. cryptomeriae. On PDA, the fungus grew over a range of about 1 to 25°C, with the optimum growth at about 15–20°C.     

Inoculation and production of container-grown red alder seedlings

Summary The inoculation ofAlnus rubra (red alder) withFrankia sp. can lead to a highly efficient symbiosis. Several factors contribute to the successful establishment of nitrogenfixing nodules: (1) quantity and quality ofFrankia inoculant; (2) time and method of inoculation; (3) nutritional status of the host plant.Frankia isolates were screened for their ability to nodulate and promote plant growth of container-grown red alder. Inoculations were performed on seedlings and seeds. Apparent differences in symbiotic performance could be seen when seeds or seedlings were inoculated. Plants inoculated at planting performed significantly better than those inoculated four weeks later in terms of shoot height, nodule number and shoot dry weight. If inoculation was delayed further, reduction in shoot height, nodule number and shoot dry weight resulted. The effect of fertilizer was also investigated with regard to providing optimal plant growth after inoculation. Plants receiving 1/5 Hoagland's solution minus nitrogen showed maximal plant growth with abundant nodulation. Plants receiving 1/5 Hoagland's solution with nitrogen showed excellent plant growth with significantly reduced nodulation.     

Role of birds in dissemination of the thread blight disease caused byCylindrobasidium argenteum

The thread blight disease of broad leaved trees caused byCylindrobasidium argenteum occurred in laurel forests over 20 yr old after clear cutting in Kyushu. Finding fruit bodies of the causal fungus was possible but very difficult in the forests. In inoculation tests using spores and infected branches harvested in the forests, we succeeded in transmission only with branches. In the forests, the disease is transmitted almost entirely by contact with infected branches. During 1989 to 1992 we found four brown-eared bulbul nests containing branches infected with the disease. In one nest, mycelia of the fungus had been transmitted to the host tree. The occurrence of the disease in forests over 20-yr-old was considered to be due to the nesting of birds in trees which provided the necessary height and closed environment.     

Ophiostomatoid fungi associated withIps cembrae in Japan and their pathogenicity of Japanese larch

Six ophiostomatoid fungi, i.e.,Ceratocystiopsis minuta, Ceratocystis laricicola, Ophiostoma brunneo-ciliatum, O. laricis, O. piceae andOphiostoma sp., were isolated from the galleries ofIps cembrae on Japanese Iarch (Larix kaempferi) logs in central Honshu, Japan. Japanese larch trees approximately 30 yr old were inoculated with all six fungi.Ceratocystis laricicola produced the largest lesions on the inner bark around the inoculation point and the largest dry zone in the sapwood. Furthermore,C. laricicola was the only fungus associated withI. cembrae that had the ability to kill Japanese larch, death occurring in 30-yr-old trees within 3.5 mo after inoculation.     

Studies in tetrapartite symbioses

Alnus incana seedlings were successfully inoculated with an endomycorrhizal fungus (Glomus fasciculatus), an ectomycorrhizal fungus (Paxillus involutus) and an isolate ofFrankia (ACN1) simultaneously. The effects of the inoculation treatments on the growth performance of the seedlings were evaluated under controlled conditions.The overall growth performance of the seedlings inoculated with the three organisms was better than those inoculated withFrankia, G. fasciculatus andP. involutus individually or withFrankia+G. fasciculatus andFrankia+P. involutus combinations. The highest growth performance and mycorrhizal infection occurred when the seedlings were inoculated simultaneously withFrankia+G. fasciculatus+P. involutus.     

Lecanosticta acicola, causal fungus of brown spot needle blight inPinus thunbergii, new to Japan

A needle blight disease with brown spots was found on ornamental trees ofPinus thunbergii in Shimane Prefecture, Japan. The causal fungus was identified asLecanosticta acicola, known as causal fungus of brown spot needle blight of pines recorded in the Americas, Europe, and China.Pinus thunbergii was heavily infected following inoculation with the fungus in June, but only slightly infected following inoculation in September. The mycelia of the fungus were raised and produced conidial masses on potato-dextrose and Waksman agars. They grew well at 20–25°C within the range of 5 to 35°C.     

Behaviour of the hyphae of<Emphasis Type="Italic"> Laccaria laccata</Emphasis> in the presence of<Emphasis Type="Italic"> Trichoderma harzianum</Emphasis> in vitro

The growth rate and the behaviour of Laccaria laccata and Trichoderma harzianum hyphae in co-culture and in the rhizosphere of 3-month-old Pinus sylvestris seedlings grown in vitro were investigated. In the interaction zone, hyphae of L. laccata became more pigmented and formed short branches growing towards the hyphae of the saprobic fungus, coiled around them and penetrated sporadically. Vacuolated hyphae of T. harzianum showed protoplasm granulation and breaks in walls followed by release of protoplasts. In the rhizosphere, the mantle hyphae of L. laccata showed a tendency to surround conidia of T. harzianum. No obvious penetration of the conidial walls by the hyphae of the mycorrhizal fungus was observed by scanning electron microscopy. Instead, in rare cases, the hyphae of L. laccata showed marked wrinkles, and a partial degradation of a mucilaginous material covering the mantle appeared to occur.     

Cerrena unicolor isolated from the mycangia of a horntail,Tremex longicollis,in Kochi Prefecture,Japan

A fungus was found to be stored in the mycangia of a horntail,Tremex longicollis, as hyphal fragments. All fungal isolates from the mycangia of 31 adult females of the horntail produced the same colonies on PDA. Basidiocarps ofCerrena unicolor occurred near the emergence hole of the horntail on a dead hackberry tree (Celtis sinensis). The cultures of this fungus were similar to those from the mycangia of the horntail in cultural characteristics. Mating between single-basidiospore mycelia ofC. unicolor and single-arthrospore mycelia from the mycangia of the horntail showed that they were compatible. These results revealed that the fungus isolated from the mycangia ofT. longicollis wasC. unicolor.     

A natural focus ofHistoplasma capsulatum var.duboisii is a bat cave

The natural reservoir ofHistoplasma capsulatum var.duboisii, the etiological agent of histoplasmosis duboisii (African histoplasmosis) is not yet known. We report the isolation ofH. capsulatum var.duboisii from soil admixed with bat guano and from the intestinal contents of a bat in a sandstone cave in a rural area, Ogbunike in Anambra State of Nigeria. Eight of 45 samples of soil admixed with bat guano yieldedH. capsulatum var.duboisii. Of the 35 bats belonging to the speciesNycteris hispida andTadirida pumila examined, only one (N. hispida) yielded this fungus from its intestinal contents. Identification of the isolates asHistoplasma was confirmed by exoantigen tests and by mating with tester strains ofH. capsulatum. In vitro conversion to large yeast from suggestive ofH. capsulatum var.duboisii was obtained on brain heart infusion agar supplemented with sheep blood and glutamine or cysteine. Pathogenicity tests with mice for all the isolates confirmed their identity by the demonstration of large yeast forms (8–15 µm in diameter) within giant cells in the infected tissues. Investigations on the possible occurrence of human infections in the area are in progress.A poster based on this work was presented at the 11th ISHAM Congress in Montreal, Canada (22–28 June 1991), La-Hoffman Roche, Basel, Switzerland kindly financed the trip of one of us (H.C.G) for the Congress.     

A new species of <Emphasis Type="Italic">Discostroma</Emphasis> and its anamorph <Emphasis Type="Italic">Seimatosporium</Emphasis> with two morphological types of conidia,isolated from the stems of <Emphasis Type="Italic">Paeonia suffruticosa</Emphasis>

Conidia of two morphologically different types, one with a basal appendage only and the other with appendage at both ends, were isolated from the stems of Paeonia suffruticosa. Single conidial isolates of both types of conidia yield identical colonies, which then produced both types of conidia on agar media depending on temperature, thus showing that both types of conidia belong to the same fungus. Seimatosporium botan is described based on its morphological characteristics. The teleomorph of the fungus was first found on sterilized P. suffruticosa stems placed on water agar, when grown at 5°C for 2 months in 12-h photoperiod. Discostroma botan is described for this fungus. The teleomorph is also found on the same host in the field.     

Inoculation and colonization of coffee seedlings (Coffea arabica L.) with the fungal entomopathogen Beauveria bassiana (Ascomycota: Hypocreales)

The fungal entomopathogen Beauveria bassiana became established as an endophyte in coffee seedlings grown in vitro and inoculated with B. bassiana suspensions in the radicle. The fungus was recovered as an endophyte 30 and 60 days postinoculation, from stems, leaves, and roots, and at 60 days postinoculation one of the isolates was also recovered as an epiphyte. Fusarium sp., Rhodotorula sp., and four bacterial morpho-species were also detected, indicating these were present as endophytes in the seed.     

Fungi associated with terrestrial orchid mycorrhizas,seeds and protocorms

The identity and ecological role of fungi in the mycorrhizal roots of 25 species of mature terrestrial orchids and in 17 species of field incubated orchid seedlings were examined. Isolates of symbiotic fungi from mature orchid mycorrhizas were basidiomycetes primarily in the generaCeratorhiza, Epulorhiza andMoniliopsis; a few unidentified taxa with clamped hyphae were also recovered. More than one taxon of peloton-forming fungus was often observed in the cleared and stained mycorrhizas. AlthoughCeratorhiza andEpulorhiza strains were isolated from the developing protocorms, pelotons of clamped hyphae were often presents in the cleared protocorms of several orchid species. These basidiomycetes are difficult to isolate and may be symbionts of ectotrophic plants. The higher proportion of endophytes bearing clamp connections in developing seeds than in the mycorrhizas is attributed to differences in the nutritional requirements of the fully mycotrophic protocorms and partially autotrophic plants. Most isolates ofCeratorhiza differed enzymatically fromEpulorhiza in producing polyphenol oxidases. Dual cultures with thirteen orchid isolates and five non-orchid hosts showed that some taxa can form harmless associations with non-orchid hosts. It is suggested that most terrestrial orchid mycorrhizas are relatively non-specific and that the mycobionts can be saprophytes, parasites or mycorrhizal associates of other plants.     

Mycosphaerella chaenomelis sp. nov.: The teleomorph ofCercosporella sp., the causal fungus of frosty mildew inChaenomeles sinensis, and its role as the primary infection source

A leaf spot disease called frosty mildew was observed onChaenomeles sinensis throughout Japan. Small brown spots with white tufts occurred followed by successive defoliation. On the fallen leaves, minute black dots are formed. The causal fungus was regarded as a new species ofMycosphaerella, M. chaenomelis, andCercosporella chaenomelis in anamorph. Pathogenicity of the fungus was confirmed only inC. sinensis by inoculation experiments. Colonies of the fungus grew well on potato sucrose agar, and grew at 10–30°C with an optimum temperature of 25°C. The fungus overwintered on the fallen diseased leaves in the form of pseudothecia, and ascospores served as the primary infection source from April to June.     

Effect of bryophytes on survival of conifer seedlings in subalpine forests of central Japan

Bryophytes form the major seedbed for coniferous trees in the subalpine forests of central Japan. Field experiments were conducted on the floor of a closed stand dominated byTsuga on Mt Fuji to examine the seedling survival ofAbies veitchii andTsuga diversifolia in seven substrate types in relation to the morphological characteristics of the seeds and seedlings. NeitherAbies norTsuga seedlings could survive on dwarf-bamboo litter beyond 2 years after the seed rain.Abies seedlings survived not only in all types of bryophyte communities but also in larch litter. In contrast, the survival ofTsuga seedlings was restricted to communities of smaller-statured bryophytes found on logs. The seeds and 1st year seedlings ofA. veitchii were larger than those ofT. diversifolia. Abies seedlings produced hypocotyls taller than any bryophyte community and radicles which were long enough to penetrate into the moist humus layer, whereasTsuga seedling radicles presumably penetrate into humus only in bryophyte communities forming a thin mat on logs. The effect of bryophytes on survival of tree seedlings therefore depends on the relationships between the morphology of seeds and seedlings and the structure of bryophyte communities.     

Didymella fagi sp. nov. and its anamorphAscochyta fagi, causing the yellow leaf spot disease ofFagus crenata andQuercus mongolica var.grosseserrata in Japan

AnAscochyta fungus was obtained during a survey of leaf spot diseases ofFagus crenata in the mountains of Aomori prefecture in 1995. The pathogenicity of the fungus toF. crenata was confirmed by inoculation. Its teleomorph was first found on artificially infected leaves after the leaves were placed in an incubator at 5°C with a 12-h photoperiod (approximately 500lx, daylight strip lamps) for 4 mo. The fungus was found to be the causal agent of yellow leaf spots ofF. crenata andQuercus mongolica var.grosseserrata in the field. Comparison with similar fungi so far described from Fagaceae indicated that the anamorph isAscochyta fagi and the teleomorph is an undescribed species ofDidymella. The nameDidymella fagi is introduced for the teleomorph. Correlation between the two morphs has been proved by cultural, morphological and pathological studies.     

The improvement and utilization in forestry of nitrogen fixation by actinorhizal plants with special reference toAlnus in Scotland

Summary Alnus species are used widely in Britain for land reclamation, forestry and other purposes. Rapid juvenile growth of the AmericanAlnus rubra makes it an attractive species for planting on N-deficient soils, particularly those of low organic content. In small plot trials, this species is nodulated by indigenous soil frankiae as effectively asAlnus glutinosa. Over a three year period both species return similar amounts of N to the ecosystem, estimated at up to 10–12 kg N ha^–1. Several strains ofFrankia have been isolated from local (Lennox Forest)A. rubra nodules. These differ morphologically and in their growth on different culture media, both from each other and fromA. glutinosa nodule isolates. AllAlnus isolates, however, have a total cellular fatty acid composition qualitatively similar to some other Group B frankiae. Glasshouse tests in N free culture suggest thatA. rubra nodules formed after inoculation of seedlings with American spore (–) isolates are three times more effective in N fixation than those inoculated with LennoxA. rubra spore (+) nodule homogenates. By contrast, the early growth of seedlings inoculated with spore (–)Frankia strains suggests at best a 35% improvement in N fixing activity over seedlings inoculated with LennoxA. rubra nodule isolates. Nevertheless, this improvement in activity, together with the better performance of seedlings inoculated with isolates compared with those treated with crushed nodule preparations, suggest that it would be worthwhile commercially to inoculate nursery stock with a spore (–)Frankia strain.     

Effect of Tilemsi phosphate rock-solubilizing microorganisms on phosphorus uptake and yield of field-grown wheat (Triticum aestivum L.) in Mali

With the broad aim of biologically improving P uptake by wheat fertilized with Tilemsi phosphate rock (TPR), we investigated the effect of inoculation with TPR-solubilizing microorganisms isolated from Malian soils and with a commercial isolate of the arbuscular mycorrhizal (AM) fungus Glomus intraradices (Gi). AM root length colonization, and growth yield and P concentration of the cultivar Tetra of wheat were measured under field conditions in Mali. Experimental plots were established in Koygour (Diré) during the 2001–2002 cropping season. Inoculation treatments included two fungal isolates, Aspergillus awamori (C1) and Penicillium chrysogenum (C13), and an isolate of Pseudomonas sp. (BR2), used alone or in fungus-bacterium combinations in the presence or absence of the AM fungus Gi. In fertilized treatments, 0 or 30 kg P ha⁻¹ was applied as TPR or diammonium phosphate (DAP). In 45-day-old wheat plants, the highest root length AM colonization (62%) was observed with TPR fertilized wheat inoculated with Gi and BR2. Our results suggest that BR2 is a mycorrhizal-helper bacteria and a good plant growth-promoting rhizobacteria. In fact, inoculation of wheat Tetra fertilized with TPR with a combination of Gi, BR2 and C1 produced the best grain yield with the highest P concentration. This work shows that by inoculating seeds with TPR-solubilizing microorganisms and AM fungi under field conditions in Mali it is possible to obtain wheat grain yields comparable to those produced by using the expensive DAP fertilizer.     

A comparison of cultural characteristics and infectivity ofFrankia isolates from root nodules ofCasuarina species

Summary The isolations of three new strains ofFrankia were made from root nodules ofCasuarina cunninghamiana growing aeroponically. Two strains, HFPCCI1 and HFPCcI2 isolated by Lopez are typicalFrankia strains, producing sporangia among filamentous mats in culture and, in the absence of combined nitrogen, forming vesicles and showing acetylene reduction. They are red-pigmented and, although failing to nodulateCasuarina hosts, effectively nodulatedElaeagnus andHippophae. A third strain HFPCcI3 isolated by Zhang from the same source, also a typicalFrankia, can form sporangia and vesicles in culture and reduce acetylene, is unpigmented, fails to nodulateElaeagnus but effectively nodulatesC. cunninghamiana andC. equisetifolia. Comparisons are made among all of theCasuarina isolates in our collection from around the world (twelve in all) with regard to their cultural characteristics and capacity to infect host plant species. Questions are raised about the specificity of the various isolates and their possible affinities. Opportunities are suggested for inoculation of seedlings for forestry and field application using the infective, effective strains now available.     

环链虫草Cordyceps cateniannulata对番茄生长和抗氧化酶活性的影响

【目的】评估环链虫草Cordyceps cateniannulata对植物促生和植物抗氧化酶活性的影响。【方法】本研究利用浸种法将环链虫草接种于番茄植物体,在接种后的第30天和60天,通过番茄株高、根长、地上和地下部分的干鲜重指标评价其对番茄生长的影响;在接种后第10、20、30、60和90天,通过选择性培养基分析其在番茄不同组织中的生存情况,使用形态学及DNA序列比对的方法检验所分离菌株与原有菌株的一致性。在处理后的第30天,检测番茄叶片中的过氧化物酶(POD)、过氧化氢酶(CAT)、超氧化物歧化酶(SOD)及丙二醛(MDA)含量,观察环链虫草对番茄的抗氧化酶活性影响。【结果】环链虫草可定殖于番茄幼苗且对番茄生长有显著促进作用,菌株对植株的定殖偏好性分别为根部>茎部>叶部。酶活检测结果表明,处理组番茄叶片防御酶活性均呈显著升高的趋势,其中POD、CAT、SOD活性分别比对照增加了52.21%、75.31%和158.59%,MDA含量下降了35.15%。【结论】环链虫草可以通过浸种的方法感染并定殖番茄幼苗的根、茎、叶,促进番茄幼苗的生长并提高番茄抗氧化酶活性,具有较好的田间...     

豚草种带内生真菌及其对种子发芽和幼苗生长的影响

内生真菌是一类共生于植物体内,能够不同程度影响宿主植物生态适应性和竞争能力的微生物。分析内生真菌在豚草种子中的分布、种群结构,以及内生真菌发酵液对种子发芽和幼苗生长的作用。结果显示:发生于6个地区的豚草种子均能分离获得内生真菌,分离率在19%—92.63%之间,不同地区之间差异极显著(P0.01)。内生真菌主要存在于种子的总苞部位,分离率达到65.52%。发生于福建省长乐市松下镇的豚草种带内生真菌种群包含5个属,以链格孢属(Alternaria)真菌为优势菌群,占82.26%;其次为镰孢属(Fusarium)真菌,占9.68%;其它3个属的真菌发生较少,均低于5%。内生真菌主要以水平传播方式在豚草不同世代之间传播。供试的7个内生真菌菌株的发酵液均不同程度地抑制豚草种子发芽,降低幼苗地上部高度、根长度、根数量和总生物量,但不同菌株发酵液之间抑制程度差异明显,显示不同菌株对豚草种子发芽和幼苗生长产生不同的影响。内生真菌发酵液处理后的种子仍然保持较高程度的活力;不同内生真菌发酵液处理后,有活力的种子维持在50%—87.5%之间,均高于(或等于)清水处理的种子,说明内生真菌代谢产物只是抑制种子的发芽,但并不导致种子的腐烂和死亡。这些研究结果初步显示种子携带的内生真菌可能在豚草入侵生物学中发挥重要的作用。