Lambertella advenula, a new combination proposed forMoellerodiscus advenulus, new to Japan

Moellerodiscus advenulus, a sclerotiniaceous fungus new to Japan, was collected and its ascospore morphology and cultural characteristics were studied. Ascospores possess previously unreported characters, such as gelatinous polar appendages and a sheath, and become brown and one-septate after discharge, prior to germination. The stromata produced in culture have a thin black rind typical ofLambertella. The taxonomic position ofM. advenulus is discussed, and a new combination,L. advenula, is proposed.     

Molecular phylogeny and evolution of Monilinia (Sclerotiniaceae) based on coding and noncoding rDNA sequences

The nuclear internal transcribed spacers, the 5.8S subunit, ~560 bp of the small subunit, and ~320 bp of the large subunit of the nuclear ribosomal DNA repeat from 17 species of Monilinia and eight species of closely related genera were sequenced. Phylogenies were constructed using maximum parsimony. The results support the hypothesis that Monilinia is not monophyletic. A fundamental distinction was found between the section Junctoriae and the section Disjunctoriae. Four evolutionary lineages were identified within the Disjunctoriae: one species on Crataegus, one group of species on dry stone fruits of rosaceous hosts, one group of species on capsular fruits of ericaceous hosts, and one group of species on sweet berry fruits of ericaceous hosts. Comparisons between branching topologies of hosts and Monilinia species suggest that although cospeciation among hosts and parasites has been the rule, several host jumps have taken place. Sclerotinia pirolae was determined to be a true member of the Disjunctoriae. The closest taxon groups to the Junctoriae were found to be Botrytis and Sclerotinia, with Ciborinia being the closest taxon group to the Disjunctoriae. There is evidence of an increased rate of ssrRNA evolution in the lineage of species that attack ericaceous berries.     

Glutamine synthetase and glutamate synthase from Sclerotinia sclerotiorum

Glutamine synthetase (GS, EC 6.3.1.2) and glutamate synthase (GOGAT, EC 1.4.1.13) were purified from Sclerotinia sclerotiorum and some of their properties studied. The GS transferase and biosynthetic activities, as well as GOGAT activity, were sensitive to feedback inhibition by amino acids and other metabolites. GS showed a marked dependence on ADP in the transferase reaction and on ATP in the Mg²⁺-dependent biosynthetic reaction. Regulation of GS activity by adenylylation/deadenylylation was demonstrated by snake venom phosphodiesterase treatment of the purified enzyme. GOGAT required NADPH as an electron donor; NADH was inactive. GOGAT was strongly inhibited by p-chloromercuribenzoate and the inhibition was reversed by cysteine. The enzyme was also markedly inhibited by o-phenanthroline, 2,2′-bipyridyl and azaserine. l-Methionine-dl-sulphoximine (MSX) and azaserine inhibited the incorporation of ¹⁵N-labelled ammonium sulphate into washed cells of S. sclerotiorum. MSX and azaserine respectively also inhibited purified GS and GOGAT activities. GDH activity was not detected in cell-extracts. Thus the GS/GOGAT pathway is the main route for the assimilation of ammonium compounds in this fungus.     

中国核盘菌科分类研究概况

本文简要回顾我国核盘菌科真菌的研究历史,尤其是最近十年的进展,更正了过去此科分类和命名中的一些问题,列出我国目前已知核盘菌科12属42种,并提供属的检索表;其中美洲杯盘菌(Ciboria americana Durand)为我国新记录。同时,指出对此科进一步深入探讨的方向。描述了新种贵州杯盘菌(Ciboria guizhouensis w.-y.Zhuang),模式保存在中国科学院微生物研究所真菌标本室。     

Nervostroma, gen. nov. in the Sclerotiniaceae, the teleomorph of Cristulariella, and Hinomyces anam. gen. nov. to accommodate the anamorph of Grovesinia: reassessment of the genus Cristulariella

Taxonomy of the genus Cristulariella is revised, retaining Cristulariella (Crist.) depraedans as the type. Two new species, Crist. cercidiphylli and Crist. corni, are additionally described under the genus. The new anamorphic genus Hinomyces is erected to accommodate Botrytis (Cristulariella) moricola and Cristulariella pruni. A new genus and species, Nervostroma depraedans, is erected in the Sclerotiniaceae to accommodate the teleomorph of Crist. depraedans, with an additional species, Nervostroma cercidiphylli.     

Melanin in the extracellular matrix of germlings of Botrytis cinerea

Previous work on the composition of the extracellular matrix of germlings of the plant pathogenic fungus Botrytis cinerea demonstrated the presence of carbohydrate, protein, and simple lipids; which, together, comprised 50-60% of the dry weight. Here we show that most of the remaining mass of the extracellular matrix consists of a chemically inert dark pigment with the electron paramagnetic resonance characteristics of a melanin. Scanning electron micrographs of the purified pigment, and transmission electron micrographs of thin sections made using the pigment indicate that it has a filamentous structure. We conclude that melanin is an important component of the extracellular matrix of germlings of B. cinerea. This is the first report of a melanin present in the extracellular matrix of a plant pathogenic fungus.     

Contrasting effects of necrotrophic and biotrophic plant pathogens on the aphid Aphis fabae

Phytophagous insects have to contend with a wide variation in food quality brought about by a variety of factors intrinsic and extrinsic to the plant. One of the most important factors is infection by plant pathogenic fungi. Necrotrophic and biotrophic plant pathogenic fungi may have contrasting effects on insect herbivores due to their different infection mechanisms and induction of different resistance pathways, although this has been little studied and there has been no study of their combined effect. We studied the effect of the biotrophic rust fungus Uromyces viciae‐fabae (Pers.) Schroet (Basidiomycota: Uredinales: Pucciniaceae) and the necrotrophic fungus Botrytis cinerea Pers. (Ascomycota: Helotiales: Sclerotiniaceae) singly and together on the performance of the aphid Aphis fabae Scopoli (Hemiptera: Aphididae) on Vicia faba (L.) (Fabaceae). Alone, botrytis had an inhibitory effect on individual A. fabae development, survival, and fecundity, whereas rust infection consistently enhanced individual aphids' performance. These effects varied in linear relation to lesion or pustule density. However, whole‐plant infection by either pathogen resulted in a smaller aphid population of smaller aphids than on uninfected plants, indicating a lowering of aphid carrying capacity with infection. When both fungi were applied simultaneously to a leaf they generally cancelled the effect of each other out, resulting in most performance parameters being similar to the controls, although fecundity was reduced. However, sequential plant infection (pathogens applied 5 days apart) led to a 70% decrease in fecundity and 50% reduction in intrinsic rate of increase. The application of rust before botrytis had a greater inhibitory effect on aphids than applying botrytis before rust. Rust infection increased leaf total nitrogen concentration by 30%, whereas infection by botrytis with or without rust led to a 38% decrease. The aphids' responses to the two plant pathogens individually is consistent with the alteration in plant nutrient content by infection and also the induction of different plant defence pathways and the possible cross‐talk between them. This is the first demonstration of the complex effects of the dual infection of a plant by contrasting pathogens on insect herbivores.     

Inhibition of Monilinia oxycocci by bacteria isolated from a cranberry marsh

Bacteria inhibitory to Moniliniaoxycocci, the cranberry cotton ball pathogen, were identified. Eighty-three bacteria isolated from a cranberry marsh and Erwinia herbicola C9-1,which is being developed elsewhere for the biological control of fire blight of pome fruits, were tested fortheir ability to inhibit radial growth and conidial germination of M. oxycocci in vitro. IsolateBA35 from cranberry (tentatively identified as Pseudomonas syringae pv. morsprunorum) and E. herbicola C9-1 completely inhibited radial growth of M. oxycocci. BA35 and C9-1 were among the most effective of 21 bacteria tested for inhibition of conidial germination. Growth of bacteria in sclerotial extracts of M. oxycocci and Sclerotinia sclerotiorum was determined in order to select isolates that might be successful in degradingsclerotia, thereby reducing the viability of M.oxycocci. Populations of isolates 62 and S-18(identities unknown), and S-19 (tentatively identified as Micrococcus luteus), increased approximately3.0--5.0 log₁₀ units in all extracts within 24 h. Populations of isolate S-10 increased by about 3.5log₁₀ units in all sclerotial extracts within 48 h. Populations of isolate S-49 (identity unknown)were lower in extracts of M. oxycocci than S. sclerotiorum after 48-h. In buffer controls, bacterial populations remained stable or decreased over the 48-h period. This revised version was published online in July 2006 with corrections to the Cover Date.