Fusarium species from nepalese rice and production of mycotoxins and gibberellic acid by selected species

Infection of cereal grains with Fusarium species can cause contamination with mycotoxins that affect human and animal health. To determine the potential for mycotoxin contamination, we isolated Fusarium species from samples of rice seeds that were collected in 1997 on farms in the foothills of the Nepal Himalaya. The predominant Fusarium species in surface-disinfested seeds with husks were species of the Gibberella fujikuroi complex, including G. fujikuroi mating population A (anamorph, Fusarium verticillioides), G. fujikuroi mating population C (anamorph, Fusarium fujikuroi), and G. fujikuroi mating population D (anamorph, Fusarium proliferatum). The widespread occurrence of mating population D suggests that its role in the complex symptoms of bakanae disease of rice may be significant. Other common species were Gibberella zeae (anamorph, Fusarium graminearum) and Fusarium semitectum, with Fusarium acuminatum, Fusarium anguioides, Fusarium avenaceum, Fusarium chlamydosporum, Fusarium equiseti, and Fusarium oxysporum occasionally present. Strains of mating population C produced beauvericin, moniliformin, and gibberellic acid, but little or no fumonisin, whereas strains of mating population D produced beauvericin, fumonisin, and, usually, moniliformin, but no gibberellic acid. Some strains of G. zeae produced the 8-ketotrichothecene nivalenol, whereas others produced deoxynivalenol. Despite the occurrence of fumonisin-producing strains of mating population D, and of 8-ketotrichothecene-producing strains of G. zeae, Nepalese rice showed no detectable contamination with these mycotoxins. Effective traditional practices for grain drying and storage may prevent contamination of Nepalese rice with Fusarium mycotoxins.     

根足虫草琅琊山变种新变种及其无性型被毛孢新种

报道采自安徽省滁州市琅琊山林场的一种虫草及其无性型,经鉴定为根足虫草琅琊山变种Cordycepsheteropodavar.langyashanensis新变种。多批次收集弹射的子囊孢子分离得到其无性型,经鉴定为一被毛孢新种,命名为根足被毛孢Hirsutellaheteropoda。模式标本及其无性型菌株干培养物保存在安徽农业大学虫生菌研究中心(RCEFAAU)。     

A new fungal genus, Teracosphaeria, with a phialophora-like anamorph (Sordariomycetes, Ascomycota)

The new genus and species Teracosphaeria petroica is described for a perithecial ascomycete and its anamorph occurring on decayed wood collected in New Zealand. The fungus produces immersed, non-stromatic ceratosphaeria-like perithecia in nature, with hyaline, septate ascospores produced in unitunicate, non-amyloid asci. The anamorph produced in vitro is phialophora-like with lightly pigmented phialides terminating in flaring, deep collarettes that are often noticeably brown with conspicuous periclinal thickening. Phylogenetic analysis of LSU rDNA sequence data indicates that this fungus is distinct from morphologically similar fungi classified in the Chaetosphaeriales, the Trichosphaeriales or the Magnaporthaceae. It forms a monophyletic group with recently described, chaetosphaeria-like ascomycetes, such as the pyrenomycete genus Mirannulata, and shows affinity with the anamorphic species Dictyochaeta cylindrospora. The usefulness of describing anamorph genera for morphologically reduced anamorphs, when anamorph characteristics are actually part of the holomorph diagnosis, is discussed. An apparently contradictory example of the so-called Cordana and Pseudobotrytis anamorphs of Porosphaerella spp. is also discussed.     

粉被虫草无性型的确证与鉴定

用从粉被虫草(Cordyceps pruinosa Petch)新鲜标本分离得到的假定无性型CGAC2281菌株,于室内人工重新养培出了粉被虫草的子实体。经观察表明,人工培养的子实体、子囊壳和次生子囊孢子的形态学特征与野外采集的标本基本相同,从而确证了CGAC 2281菌株是粉被虫草的真正无性型。本文报道了这种真菌的形态学特征,并鉴定它为马利亚霉属一新种,粉被马利亚霉新种(Mariannaea pruinosa Liang sp.nov.)。     

莲状虫草及其刺束梗孢无性型

报道采自安徽省万佛山自然保护区的一种寄生在蜘蛛上的虫草标本,经鉴定为莲状虫草Cordycepsnelumboides。经多批次利用子囊孢子分离得到其刺束梗孢无性型Akanthomyces,属首次报道,并在人工固体培养基上得到了与野生标本一致的子实体,从丽确证了有性型与元性型之间的对应关系。经研究发现,KOBAYASI和SHIMIZU对莲状虫草次生子囊孢子的原始描述可能有误。     

Fusarium Species from Nepalese Rice and Production of Mycotoxins and Gibberellic Acid by Selected Species

Infection of cereal grains with Fusarium species can cause contamination with mycotoxins that affect human and animal health. To determine the potential for mycotoxin contamination, we isolated Fusarium species from samples of rice seeds that were collected in 1997 on farms in the foothills of the Nepal Himalaya. The predominant Fusarium species in surface-disinfested seeds with husks were species of the Gibberella fujikuroi complex, including G. fujikuroi mating population A (anamorph, Fusarium verticillioides), G. fujikuroi mating population C (anamorph, Fusarium fujikuroi), and G. fujikuroi mating population D (anamorph, Fusarium proliferatum). The widespread occurrence of mating population D suggests that its role in the complex symptoms of bakanae disease of rice may be significant. Other common species were Gibberella zeae (anamorph, Fusarium graminearum) and Fusarium semitectum, with Fusarium acuminatum, Fusarium anguioides, Fusarium avenaceum, Fusarium chlamydosporum, Fusarium equiseti, and Fusarium oxysporum occasionally present. Strains of mating population C produced beauvericin, moniliformin, and gibberellic acid, but little or no fumonisin, whereas strains of mating population D produced beauvericin, fumonisin, and, usually, moniliformin, but no gibberellic acid. Some strains of G. zeae produced the 8-ketotrichothecene nivalenol, whereas others produced deoxynivalenol. Despite the occurrence of fumonisin-producing strains of mating population D, and of 8-ketotrichothecene-producing strains of G. zeae, Nepalese rice showed no detectable contamination with these mycotoxins. Effective traditional practices for grain drying and storage may prevent contamination of Nepalese rice with Fusarium mycotoxins.     

Lignicolous freshwater Ascomycota from Thailand: Hymenoscyphus varicosporoides and its Tricladium anamorph

A Tricladium anamorph for the discomycete Hymenoscyphus varicosporoides was established in culture from both conidia and ascospores collected in KhaoYai National Park, Thailand, and is compared with Tricladium indicum and T. marylandicum. Hymenoscyphus varicosporoides is compared with Cudoniella indica.     

Seed Rot,a New Disease of Beech Tree Caused by Neonectria ramulariae (anamorph: Cylindrocarpon obtusiusculum)

During a survey of seed diseases of Fagus crenata, a new fungal disease of the seeds was found with high frequency in Akita, northern Japan. Main symptoms are often expressed as browning of the cracked parts from exposed cotyledons and complete loss of viability of infected seeds. Reddish perithecia and whitish yellow sporodochia were occasionally observed symptoms and determined that they were anamorph–telemorph relationship on the basis of both cultural observations. Inoculation studies confirmed that this fungus was the cause of seed rot. The fungus is morphologically identical with Neonectria ramulariae (anamorph: Cylindrocarpon obtusiusculum) that is well known as the soil‐born fungi around the world. Sequences between the authentic isolate of Neo. ramulariae (CBS 151.29) and the pathogenic fungus based on ITS, LSU and tub showed high similarity. Thus, ‘seed rot’, the new disease of beech seeds caused by Neo. ramulariae (anamorph: Cyl. obtusiusculum) was proposed in this study.     

高雄山虫草及其细脚拟青霉无性型

报道采自安徽省天堂寨自然保护区的高雄山虫草Cordyceps takaomontana及其无性型细脚拟青霉Paecilomyces tenuipes ,应用单子囊孢子分离鉴定和微循环产孢的方法确证了两者的对应关系,并修订了高雄山虫草的原始描述。双梭孢虫草C．bifusispora可能为高雄山虫草的同物异名。同时采集的具数个红色子座且有双梭形子囊孢子的虫草不是同一个种。     

Hypocrea voglmayrii sp. nov. from the Austrian Alps represents a new phylogenetic clade in Hypocrea/Trichoderma

The holomorph of the new species Hypocrea voglmayrii (Hypocreales, Ascomycota, Fungi) is described by a combined approach, using morphology of the teleomorph, morphology of the anamorph, culture studies and phylogenetic analyses of ITS1 and 2, ech42 and rpb2 gene sequences. Its anamorph Trichoderma voglmayrii is described as a new anamorph species. Unlike most other species of Hypocrea the teleomorph of H. voglmayrii occurs on dry standing trunks and exhibits well defined black ostioles. Although exclusively collected at higher altitudes, this species grows at 35 C in culture. Hypocrea voglmayrii develops pale yellowish to greenish conidia, a yellowish pigment and a coconut-like odor on CMD. Phylogenetically, H. voglmayrii forms a distinct, isolated branch between the section Trichoderma and the H. pachybasioides clade but does not associate with any of these clades in different gene trees.     

高雄山虫草及其细脚拟青霉无性型

报道采自安徽省天堂寨自然保护区的高雄山虫草Cordyceps takaomontana及其无性型细脚拟青霉Paecilomyces tenuipes,应用单子囊孢子分离鉴定和微循环产孢的方法确证了两者的对应关系,并修订了高雄山虫草的原始描述。双梭孢虫草C．Bifusispora可能为高雄山虫草的同物异名。同时采集的具数个红色子座且有双梭形子囊孢子的虫草不是同一个种。     

Hypocrea lixii, the teleomorph of Trichoderma harzianum

Cultures derived from ascospores of Hypocrea lixii (= H. nigricans, H. lentiformis) produced the morphological species Trichoderma harzianum in pure culture. Trichoderma harzianum, the most commonly found species of the genus, is also one of the most species frequently used in biocontrol of plant pathogens. It has not been connected previously to a teleomorph. The connection was confirmed by DNA sequence analysis. Similar to the anamorph, the teleomorph collections have a wide geographic distribution. Described in the 19^th century, Hypocrea lixii is epitypified by a collection from Thailand.     

菜豆炭疽菌有性态研究

在引起菜豆炭疽病的 Colletotrichum lindemuthianum (Sacc. Et Magn．)Br. EtCav．大量培养物中,发现一个在低温培养保存中丧失产生分生孢子能力而仅产生子囊壳的菌系。对其形态学、培养特征、单子囊孢子培养的研究及与有关种的形态比较结果表明,这个源于分生孢子的子囊菌培养物是菜豆小丛壳Glomerella lindemuthianum Shear。这个培养物经人工接种菜豆,再分离时首先产生无性态分生孢子,经数代培养又回复有性态,表明有性过程的产生是同宗配合的。这种有性与无性阶段之间的交替和联系,证明这是一个全型态真菌,即菜豆小丛壳 G. lindemuthianum 是无性态荣豆炭疽菌C．Lindemuthianum 的有性态。     

Erysiphe abbreviata on cherry bark oak--morphology, phylogeny and taxonomy

Powdery mildew on cherry bark oak (Quercus falcate var. pagodifolia) collected in Tennessee, USA, was determined to be Erysiphe abbreviata, a species confined to North America. The diagnostically important anamorph of this species is described for the first time. Sequence analyses of the rDNA ITS region and D1/D2 domains of the 28S rDNA were used to obtain phylogenetic data for and taxonomic conclusions about this species. The structure of the anamorph (Oidium subgen. Pseudoidium) and the molecular data support the placement of this species in Erysiphe emend. (including Microsphaera) as a species separate from the Eurasian Erysiphe alphitoides.     

Exudation of an allelopathic substance lepidimoide from seeds during germination

Lepidimoide promotes growth of the cockscomb hypocotyl. It is exuded from germinating seeds of various plant species into their culture environment. The mode of exudation of lepidimoide from seeds into the culture solution, using sunflower and buckwheat seeds, was studied in relation to seed germination. In the dry seeds, about 75% of the lepidimoide was found in the seed coat and about 25% in the kernel. Upon water imbibition it was released into the culture solution. However, the quantity of lepidimoide detected in the seed exudate was more than three times the total amount in dry and imbibed seeds, suggesting that lepidimoide was also produced de novo in the seeds and subsequently released. When seed coats or kernels were imbibed separately, the quantity of lepidimoide released from the seed coats into the culture solution was much the same as that in the dry seeds, but the amount of lepidimoide detected in the exudate of kernels was about 16 times that in the dry kernels. These results suggest that lepidimoide, already present in dry seeds, as well as that newly produced in the kernels following imbibition, was released into the environment.     

A method to produce encapsulatable units for synthetic seeds in Asparagus officinalis

A method to produce encapsulatable units for synthetic seeds was developed in Asparagus officinalis L. Encapsulatable units with high conversion ability in non-sterile soil were produced from somatic embryos by a pre-encapsulation culture. The synthetic seeds containing somatic embryos without the pre-encapsulation culture did not germinate in soil. When the pre-encapsulation culture medium did not contain growth regulators, the roots elongated too much to accomplish encapsulation. Several growth regulators were studied and indole-3-acetic acid was considered to be optimum at 28.5 M. The pre-encapsulation culture medium with indole-3-acetic acid inhibited the growth of roots during the pre-encapsulation culture and produced compact encapsulatable units. The growth of roots was promoted when plants were produced from the encapsulatable units. The percent conversion of the synthetic seeds with these encapsulatable units was 72% in non-sterile soil. This is the first report on synthetic seeds in Asparagus officinalis L.     

Thielavia aurantiaca, a new species from Japanese soil

A new species ofThielavia (T. aurantiaca) isolated from field soil collected from Osaka is described and illustrated. The fungus is distinguished from other known species by having ascomata covered with yellowish orange mycelium and smaller size of ascomata and ascospores. A chlamydospore-like anamorph is formed.     

Hirsutella uncinata, a new hyphomycete from Australia

Hirsutella uncinata, collected on follicles of Hakea sp. in New South Wales, Australia, is described as a new anamorph species. The fungus produces stiff, erect, verticillate conidiophores with up to 10 whorls of hooked, phialidic conidiogenous cells that have rough-walled necks. The conidia are subfusiform, flattened on one side and produced in groups of 2-3 in a dense slimy ball at the end of each phialide. Parsimony analysis of aligned internal transcribed spacer rDNA sequences suggests that H. uncinata is closely related to the Cordyceps sinensis complex (Clavicipitaceae, Hypocreales), which includes species with morphologically similar anamorphs.     

Sclerotinia nivalis, sp. nov., the pathogen of snow mold of herbaceous dicots in Northern Japan

A newSclerotinia, previously reported asS. intermedia from Japan, is described asSclerotinia nivalis on the morphological basis of the sclerotial anamorph and teleomorph produced in culture. The characters assigning this species to the genusSclerotinia are the tuberoid sclerotia superficially produced on suscepts, the small sclerotia produced on aerial mycelium in culture, the interhyphal spaces in medullary tissue of sclerotia, and the globose cells constructing the ectal excipulum of apothecia. It is distinguishable fromS. sclerotiorum, S. minor, andS. trifoliorum by the intermediate sized sclerotia in culture, binucleate ascospores, the molecular mass of major proteins of sclerotia, and the patterns of esterase isozymes in sclerotial extracts. AlthoughS. nivalis causes snow mold of various dicots, it is a mesophile having an optimum temperature for mycelial growth of around 20°C. It attacks edible burdock(Arctium lappa), Chryhsanthemum morifolium, Ambrosia elatior, carrot(Daucus carota), Angelica acutiloba, Ajuga reptans, andPlantago lanceolata.     

Seed germination and seedling morphology of the seagrass,Halophila engelmannii (Hydrocharitaceae)

Seeds of Halophila engelmannii Aschers., that were collected in Redfish Bay, Texas, at weekly intervals from mid-May to mid-June 1986, began to germinate 3–4 weeks after collection. Most of the collections subsequently showed an increase in the rate of germination under increased light intensity and all had a stoppage of germination after transfer to darkness, indicating a light requirement to break endogenous seed dormancy. During the 5 weeks after seeds germinated, seedlings in soil culture produced a rosette of six leaves before the appearance of a rhizome bud in the axil of the third leaf. The first node of the rhizome produced a root and an upright shoot with a pseudowhorl of three to five leaves.