The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform

Wonbo Shim - One of the best experts on this subject based on the ideXlab platform.

  • a conserved homeobox transcription factor htf1 is required for Phialide development and conidiogenesis in fusarium species
    PLOS ONE, 2012
    Co-Authors: Wenhui Zheng, Xu Zhao, Qingping Huang, Chengkang Zhang, Huanchen Zhai, Liping Xu, Guodong Lu, Wonbo Shim
    Abstract:

    Conidia are primary means of asexual reproduction and dispersal in a variety of pathogenic fungi, and it is widely recognized that they play a critical role in animal and plant disease epidemics. However, genetic mechanisms associated with conidiogenesis are complex and remain largely undefined in numerous pathogenic fungi. We previously showed that Htf1, a homeobox transcription factor, is required for conidiogenesis in the rice pathogen Magnaporthe oryzae. In this study, our aim was to characterize how Htf1 homolog regulates common and also distinctive conidiogenesis in three key Fusarium pathogens: F. graminearm, F. verticillioides, and F. oxysporum. When compared to wild-type progenitors, the gene-deletion mutants in Fusarium species failed to form conventional Phialides. Rather, they formed clusters of aberrant Phialides that resembled elongated hyphae segments, and it is conceivable that this led to the obstruction of conidiation in Phialides. We also observed that mutants, as well as wild-type Fusaria, can initiate alternative macroconidia production directly from hyphae through budding-like mechanism albeit at low frequencies. Microscopic observations led us to conclude that proper basal cell division and subsequent foot cell development of macroconidia were negatively impacted in the mutants. In F. verticillioides and F. oxysporum, mutants exhibited a 2- to 5- microconidia complex at the apex of monoPhialides resulting in a floral petal-like shape. Also, prototypical microconidia chains were absent in F. verticillioides mutants. F. graminearum and F. verticillioides mutants were complemented by introducing its native HTF1 gene or homologs from other Fusarium species. These results suggest that Fusarium Htf1 is functionally conserved homeobox transcription factor that regulates Phialide development and conidiogenesis via distinct signaling pathways yet to be characterized in fungi.

Randolph S Currah - One of the best experts on this subject based on the ideXlab platform.

  • Phialide arrangement and character evolution in the helotialean anamorph genera cadophora and phialocephala
    Mycologia, 2012
    Co-Authors: Jocelyn C Hall, Randolph S Currah
    Abstract:

    The dematiaceous hyphomycete genera Cadophora and Phialocephala are anamorphs associated with mollisioid inoperculate discomycetes (Helotiales) and are delineated based on the complexity of the Phialide arrangement with members of Cadophora producing solitary Phialides and species of Phialocephala producing complex heads of multiple Phialides. A third phylogenetically related taxon, Leptodontidium orchidicola, produces mostly indehiscent conidia that may represent non-functional Phialides. Morphological characteristics of both sexual and asexual states of these and other fungi in a focal group of helotialean taxa were re-examined, in light of relationships shown by molecular phylogenetic analyses of rDNA ITS sequences, to determine the evolutionary significance of Phialide arrangement. The focal species of Phialocephala formed a monophyletic clade, while five of six species of Cadophora including the type were in a separate clade along with L. orchidicola. C. finlandica was placed in a third clade with sp...

  • Pleomorphic conidiogenesis among strains of Knufia cryptophialidica
    Botany, 2005
    Co-Authors: Akihiko Tsuneda, Randolph S Currah
    Abstract:

    Pleomorphic conidiogenesis was examined in four strains of Knufia cryptophialidica Hutchison & Untereiner in culture. The ex-type strain (DAOM 216555) was the most plastic, exhibiting various patterns of conidiogenesis, and was the only strain that produced Phialides, that is, the most important diagnostic structure of the genus, although many of these Phialides were aberrant and produced abnormally swollen conidia that appeared to lack cytoplasm. Subsequently, hyphae emerged from the aberrant Phialides and some of these hyphae later disarticulated to form thallic-arthric conidia. The ex-type strain ceased to produce normal Phialides after several serial transfers onto malt extract agar. Endoconidiogenesis in K. cryptophialidica, reported here for the first time, involved subdivision of conidiogenous cells by septation and schizolysis through the septa, and their release was by rupture and subsequent degeneration of the conidiogenous cell wall. Both thallic-arthric and endogenous conidia occurred in all s...

Jian Zhang - One of the best experts on this subject based on the ideXlab platform.

  • estimated divergence times of hirsutella asexual morphs in ophiocordyceps provides insight into evolution of Phialide structure
    BMC Evolutionary Biology, 2018
    Co-Authors: Jiaojiao Qu, Yeming Zhou, Jianping Yu, Jian Zhang
    Abstract:

    Background Hirsutella Pat genus, the asexual morphs of the Ophiocordyceps Sung, is globally distributed entomopathogenic fungi, which infect a variety of arthropods, mites and nematodes. The fungal species also have shown potential application in the field of biological control, bio-medicine and food development. Although these fungi are synonymized under Ophiocordyceps, formal taxonomic assignments remain necessary for classification of species in Hirsutella. However, due to the heterogeneity and complexity of Hirsutella genus, more detailed taxonomic and phylogenetic analyses are required to address the following subjects: (1) the relationships between the Phialide morphological characteristics and phylogenetic information of Hirsutella with asexual morphs, (2) the origin and evolution of the Phialide structure, and (3) host specificity and fungal pathogenicity.

Josep Guarro - One of the best experts on this subject based on the ideXlab platform.

  • New acremonium-like species in the Bionectriaceae and Plectosphaerellaceae
    Mycological Progress, 2017
    Co-Authors: Alejandra Giraldo, Josepa Gené, Deanna A. Sutton, Nathan Wiederhold, Josep Guarro
    Abstract:

    Several molecular studies have demonstrated that species traditionally assigned to the form genus Acremonium are polyphyletic, while Acremonium sensu stricto is a central element of the family Bionectriaceae (Hypocreales). Based on phenotypic characters and molecular phylogenetic analyses, two new Acremonium species, A. moniliforme and A. dimorphosporum , are described. The former is related to Emericellopsis and is characterised by cylindrical conidia, acicular Phialides and abundantly formed moniliform hyphae. Acremonium dimorphosporum resembles A. borodinense . It produces dimorphic conidia that are either cylindrical and smooth-walled or ellipsoidal and rough-walled. The new genus Brunneomyces is proposed based on three species, including B. brunnescens (formerly A. brunnescens ), B. europaeus and B. hominis . They are characterised by brown hyphae, sympodial conidiophores and chains of ovoidal to ellipsoidal conidia. Chordomyces albus sp. nov. is characterized by its light-coloured colonies, simple or branched conidiophores, Phialides with percurrent proliferations and cylindrical collarettes, and ellipsoidal to cylindrical conidia. The combined analysis of the LSU, ITS, RPB2 and TEF1-α loci supports the inclusion of B. brunnescens , B. europaeus , B. hominis and C. albus in Plectosphaerellaceae.

  • Two new species of Cladorrhinum
    Mycologia, 2011
    Co-Authors: Hugo Madrid, Josep Cano, Josepa Gené, Josep Guarro
    Abstract:

    Two new species of Cladorrhinum, C. flexuosum and C. microsclerotigenum, are described and their sequences of the 5.8S and 28S ribosomal DNA and internal transcribed spacers 1 and 2 of the ribosomal RNA gene cluster analyzed. Cladorrhinum flexuosum, isolated from soil in Spain, forms fast-growing, dull yellow colonies, flexuous conidiophores and globose to dacryoid conidia. Cladorrhinum microsclerotigenum, isolated from Musa sp. in Turkey, strongly resembles Cladorrhinum phialophoroides in the production of abundant terminal Phialides, ellipsoid conidia and microsclerotia in culture. It differs from C. phialophoroides in its ability to grow at 36 C and high number of intercalary Phialides, which only infrequently occur in C. phialophoroides.

Lizel Mostert - One of the best experts on this subject based on the ideXlab platform.

  • Short title: Phaeocremonium species Novel Phaeoacremonium species associated with Petri disease and esca of grapevine in Iran and Spain
    2020
    Co-Authors: David Gramaje, Josep Armengol, Hamid Mohammadi, Zia Banihashemi, Lizel Mostert
    Abstract:

    Eight Phaeoacremonium (Pm.) isolates from grapevines in Iran and Spain were studied with morphological and cultural characteristics as well as phylogenetic analyses of combined DNA sequences of the actin and �� -tubulin genes. Two new species are described. Pm. cinereum was isolated from a young vine in Spain and from older vines in Iran and can be identified by its distinct gray colonies on malt extract agar, an optimum growth temperature of 25 C and subulate type III Phialides. Pm. hispanicum was isolated only once from a young vine in Spain and can be identified by the common occurrence of percurrently rejuvenating Phialides, an optimum growth temperature of 20 C and predominant type II Phialides.

  • Novel Phaeoacremonium species associated with Petri disease and esca of grapevine in Iran and Spain
    Mycologia, 2009
    Co-Authors: David Gramaje, Josep Armengol, Hamid Mohammadi, Zia Banihashemi, Lizel Mostert
    Abstract:

    Eight Phaeoacremonium (Pm.) isolates from grapevines in Iran and Spain were studied with morphological and cultural characteristics as well as phylogenetic analyses of combined DNA sequences of the actin and b-tubulin genes. Two new species are described. Pm. cinereum was isolated from a young vine in Spain and from older vines in Iran and can be identified by its distinct gray colonies on malt extract agar, an optimum growth temperature of 25 C and subulate type III Phialides. Pm. hispanicum was isolated only once from a young vine in Spain and can be identified by the common occurrence of percurrently rejuvenating Phialides, an optimum growth temperature of 20 C and predominant type II Phialides.