Smooth Conidia Research Articles

Two new species of Solicorynespora from Spain

Solicorynespora insolita sp. nov. and Solicory-nespora biseptata sp. nov., collected from plant debris in natural areas of Spain, are described and illustrated. The former species is characterized by obclavate to fusiform, 4- to 7-septate, dark brown conidia, with a mucous tunica at the apex; sometimes with an unusual oblong to bacilliform, hyaline, phialidic conidial synanamorph arising from the apical cell. Analysis of D1/D2 region rDNA sequences revealed that this fungus is related to members of the family Kirschsteiniotheliaceae of the Dothideomycetes. Solicorynespora biseptata is distinguished by obclavate, 2-septate, brown, but pale brown at the apex, smooth conidia. This latter fungus did not grow in culture. A key to species of Solicorynespora is provided.

Microfungi from Portugal: Minimelanolocus manifestus sp. nov. and Vermiculariopsiella pediculata comb. nov.

Two microfungi from a forest in Portugal are described and illustrated. The new species Minimelanolocus manifestus is distinguished by polyblastic, integrated, sympodial conidiogenous cells, and solitary, cymbiform, (2−)3-septate, smooth conidia with pale brown middle cells and subhyaline end cells. A new combination Vermiculariopsiella pediculata is proposed for Gyrothrix pediculata.

DETECTION OF THE WOOD DECAY ASCOMYCETE KRETZSCHMARIA DEUSTA IN URBAN MAPLE TREES IN ITALY

In June 2008, a basal stem failure of a sycamore maple tree (Acer pseudoplatanus) occurred in Turin (Italy). The failed tree did not show any external signs of fungal disease. However, the wood at the point of stem breakage was decayed and permeated by black lines. Isolations from decayed wood samples, performed on potato dextrose agar (PDA), yielded white fungal colonies that later turned greyish-brown producing hyaline, smooth and ovate conidia (5.5-7×2.5-3.5 μm) on tufts of sparsely branched conidiophores. Using a multiplex PCR assay (Nicolotti et al., 2009), the fungal cultures were identified as Kretzschmaria deusta. The features of the decayed wood and the morphological traits of pure cultures were also consistent with this diagnosis. After this finding, 77 maple trees, comprising those adjacent to the failed tree, were surveyed and sampled using the drilling method by Guglielmo et al. (2010). Although no overt signs of K. deusta in- fection were observed, multiplex PCR identified this fungus in five trees, comprising four sycamore maples and a Norway maple (Acer platanoides). Three of these infected trees were very close to the failed one, thus suggesting a clustering of infection. Inci- dence of K. deusta was higher than that of other wood decay fun- gi detected by multiplex PCR. Although K. deusta is known as a threat for the stability of different broadleaf trees in the urban context of northern and central Europe, to our knowledge this is the first report of this pathogen in urban maple trees in Italy.

First Report of Brown Stripe of Saltgrass Caused by Bipolaris heveae in Colorado.

Inland saltgrass (Distichlis spicata var. stricta (L.) Greene) is indigenous to western North America and Australia and is a dioecious, rhizomatous, perennial, warm-season grass. It is commonly found in areas where salinity, alkalinity, and drought have eliminated many other types of vegetation (1). It has potential for revegetation of mine spoils or use along roadsides (2). During September 2004, multiple lenticular, brown lesions were observed on leaves of saltgrass accession no. 1023 at the Horticulture Field Research Center, Colorado State University, Fort Collins. Segments of symptomatic leaf tissue were surface sterilized in 0.5% sodium hypochlorite and placed on one-quarter-strength potato dextrose agar and incubated at 25°C in the dark. Dark green fungal colonies with aerial mycelium consistently grew on the medium. Slightly curved, ellipsoidal, pale-to-golden brown, smooth conidia 46 to 80 μm long and 13 to 17 μm wide (average 64.5 × 14.7 μm) with 6 to 9 septations formed after 7 days in cultures grown on V8 juice agar. The morphology and bipolar germination of conidia was consistent with the genus Bipolaris, however, conidia were often shorter than previously reported (3). The rDNA internal transcribed spacer (ITS) regions of one isolate were amplified using polymerase chain reaction (PCR) with universal fungal rDNA primers ITS1 and ITS4. PCR products were sequenced (555 bp) and exhibited 99% nucleotide identity to Bipolaris heveae isolates collected from zoysiagrass and bermudagrass in Japan (3) and rubber in Nigeria (4). To confirm pathogenicity, a suspension of 104 conidia per ml of water containing 0.1% Tween 20 was sprayed on saltgrass leaves to runoff. Plants were covered with transparent plastic bags and incubated at 25°C in the dark. After 72 h, the bags were removed and plants were placed in the greenhouse. Brown stripe symptoms were observed on all plants after 7 days, and B. heveae was consistently isolated from symptomatic tissue. To our knowledge, this is the first report of brown stripe on inland saltgrass caused by B. heveae.

Taxonomy and biocontrol potential of a new species of Trichoderma from the Amazon basin of South America

The new species Trichoderma ovalisporum is described and its biocontrol potential against Crinipellis species is analyzed. Using partial nuclear translation elongation factor 1α (EF-1α) and partial nuclear actin gene intron and exon sequences, T. ovalisporum is identified as a member of Trichoderma sect. Trichoderma and as a close relative of T. koningii-like taxa that have ellipsoidal to oblong, smooth conidia. Sequences of the internal transcribed spacer regions 1 and 2 (ITS) of the nuclear ribosomal gene cluster did not resolve the phylogeny of T. ovalisporum and its closest relatives. Trichoderma ovalisporum is morphologically similar to T. koningii, Hypocrea stilbohypoxyli, and three as yet undescribed Trichoderma taxa. It differs from its close relatives in having smaller, ovoidal conidia and in its fast rate of growth at 30 °C. Trichoderma ovalisporum was isolated twice: once from witches’ broom (Crinipellis perniciosa)-infected tissue of a liana (Banisteriopsis caapi, Malpighiaceae) collected in Ecuador. The second isolation was from the healthy bole of a mature tree of Theobroma grandiflorum (cupuacu, Malvaceae) collected in Brazil (Para). The liana isolate reinfected and was reisolated from meristematic tissues of seedlings of Theobroma cacao, and inhibited radial growth of the frosty pod rot pathogen (Crinipellis roreri) in vitro. It also persisted on the surface, and within the tissues, of cocoa pods in the field for at least 10 weeks.

Molecular and phenotypic descriptions of Stachybotrys chlorohalonata sp. nov. and two chemotypes of Stachybotrys chartarum found in water-damaged buildings

Twenty-five Stachybotrys isolates from two previous studies have been examined and compared, using morphological, chemical and phylogenetic methods. The results show that S. chartarum sensu lato can be segregated into two chemotypes and one new species. The new species, S. chlorohalonata, differs morphologically from S. chartarum by having smooth conidia, being more restricted in growth and producing a green extracellular pigment on the medium CYA. S. chlorohalonata and S. chartarum also have different tri5, chs1 and tub1 gene fragment sequences. The two chemotypes of S. chartarum, chemotype S and chemotype A, have similar morphology but differ in production of metabolites. Chemotype S produces macrocyclic trichothecenes, satratoxins and roridins, while chemotype A produces atranones and dolabellanes. There is no difference between the two chemotypes in the tub1 gene fragment, but there is a one nucleotide difference in each of the tri5 and the chs1 gene fragments.

Variation in culture and rDNA among isolates of Sphaeropsis sapinea from Ontario and Manitoba

Three morphotypes were recognized among Manitoba and Ontario isolates of Sphaeropsis sapinea. Variation in culture was assessed based on overall culture morphology, growth rates, and conidial characteristics. Morphotypes A and B conform to previously described morphotypes, but an intermediate morphotype with smooth conidia was designated as morphotype I. Morphotype A isolates were collected from a number of Pinus species as well as Picea pungens. Morphotype B was only recovered from Picea mariana on stressed sites in Ontario, and Pinus banksiana and Pinus resinosa in Manitoba. Morphotype I was recovered from Pinus species and Picea glauca. Restriction fragment length polymorphism analysis of the ribosomal repeat unit grouped the isolates into three classes, or ribotypes, which appear to correspond to the A, B, and 1 morphotypes. All three morphotypes have been collected in Ontario. Restriction fragment length polymorphism analysis of the rDNA repeat unit may therefore be useful in distinguishing Lhe different types of this tree pathogen and might be applied to assess the occurrence and distribution of the different morphotypes.

Three new Aspergillus species isolated from clinical sources as a causal agent of human aspergillosis

Three new species ofAspergillus isolated from clinical sources in China are described and illustrated:A. beijingensis, A. qizutongii andA. wangduanlii. The first species is characterized by spreading colonies, yellow to grayish green conidial heads, smooth-walled conidiophores with a clavate vesicle, uniseriate aspergilla and nearly globose, micro-verrucose conidia. The second is characterized by spreading colonies, olive-yellow conidial heads, conspicuously roughened conidiophores with a flask-shaped vesicle, uniseriate but often secondarily proliferating aspergilla and globose, smooth conidia. The third is characterized by rapidly growing colonies, dull green conidial heads, smooth to irregularly roughened conidiophores which are often surrounded by coiled hyphae in the basal part and are terminally swollen into a globose or irregular shaped vesicle, uniseriate aspergilla and globose, micro-verrucose conidia.

New species of Endophragmiella and Sporidesmiella from Cuba

Two new taxa from rain forest in Cuba are described and illustrated. They are Endophragmiella sphaeroproliferata anam. sp. nov., characterized by cymbiform, 3-septate, pale brown, smooth conidia, and Sporidesmiella intermedia anam. sp. nov., distinguished by obovoid, 2-5 distoseptate, pale brown to subhyaline conidia. A comparative tabulation of the described species of Sporidesmiella is provided.

Heliocephala zimbabweensis sp. nov. from southern Africa

Heliocephala zimbabweensis sp. nov. collected in Zimbabwe on a rotten leaf, is described as the second species in the genus Heliocephala. The present collection is the first record of the genus in Africa. Heliocephala zimbabweensis differs from the type species, H. proliferans, in possessing completely smooth conidia ending in a straight rostrum, and with a darker median cell.

Nutrient depletion and sporulation in the wet bubble pathogen Mycogone perniciosa

On malt extract agar Mycogone perniciosa formed abundant thin-walled, hyaline phialoconidia and thick-walled, pigmented, verrucose conidia. During nutrient depletion other propagules appeared; namely lateral smooth conidia, inflated intercalary cells, chlamydospores and arthroconidia. When growing from a carbon-rich to a relatively carbon-poor medium M. perniciosa produced greater numbers of thick-walled conidia on the poorer medium. Growth from a nitrogen-rich to a relatively nitrogen-poor medium resulted in reduced production of both spore types. The ecophysiological significance of these observations is discussed.

Variation Among South African Isolates ofSphaeropsis sapinea

Swart, w. J., Wingfield, M. J., PaJmer, M. A., and Blanchette, R. A. 1991. Variation among South African isolates of Sphaeropsissapinea. Phytopathology 810489-493. Ten isolates of Sphaeropsis sapinea (syn. Diplodia pinea) obtained from various natural!y infected Pinus spp. in South Africa were screened for differences in cultural characteristics, virulence, and isozyme profiles of five enzymes. Considerable variation among isolates existed in the length and width of conidia, but this did not allow for the separation of isolates into specific groups. Scanning electron microscopy revealed that two isoJates had distinct pits over the entire outer surface of 30m-of the conidia examined. Three isolates consistently had smooth conidia, and five isolates were considered intermediate. The latter had some entirely smooth conidia and some ,.-ilhsmaJ1 indentations that were not distinct pits and occurred on only parts of individual conidia. Three isolates grew more slowly (P = O.OJ) on five culture media tested and at 20 and 25 C on malt Additional keywords: isozyme analysis, Pinus radiata. extract agar. There was a significant positive correlation between in vitro growth rate and virulence of the 10 isolates in growth chamber and field inoculations. The isozyme banding patterns of the three isolates with smooth.wa!Jed conidia and four intermediate isolates were identical to those of a typical smooth-spored isolate of S. sapinea from the north central United States for each of the five enzymes tested. The banding patterns of the two isolates with pitted conidia and one intermediate isolate were identical to those of isolates that had smooth conidia for all enzymes except malic dehydrogenase. None of the 10 local isolates displayed banding patterns associated with a typical isolate of s. sapinea having pitted conidia from the north central United States.