The genus Cercospora contains numerous important plant pathogenic fungi from a diverse range of hosts. Most species of Cercospora are known only from their morphological characters in vivo. Although the genus contains more than 5 000 names, very few cultures and associated DNA sequence data are available. In this study, 360 Cercospora isolates, obtained from 161 host species, 49 host families and 39 countries, were used to compile a molecular phylogeny. Partial sequences were derived from the internal transcribed spacer regions and intervening 5.8S nrRNA, actin, calmodulin, histone H3 and translation elongation factor 1-alpha genes. The resulting phylogenetic clades were evaluated for application of existing species names and five novel species are introduced. Eleven species are epi-, lecto- or neotypified in this study. Although existing species names were available for several clades, it was not always possible to apply North American or European names to African or Asian strains and vice versa. Some species were found to be limited to a specific host genus, whereas others were isolated from a wide host range. No single locus was found to be the ideal DNA barcode gene for the genus, and species identification needs to be based on a combination of gene loci and morphological characters. Additional primers were developed to supplement those previously published for amplification of the loci used in this study.Taxonomic novelties:New species - Cercospora coniogrammes Crous & R.G. Shivas, Cercospora delaireae C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora euphorbiae-sieboldianae C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora pileicola C. Nakash., Crous, U. Braun & H.D. Shin, Cercospora vignigena C. Nakash., Crous, U. Braun & H.D. Shin. Typifications: epitypifications - Cercospora alchemillicola U. Braun & C.F. Hill, Cercospora althaeina Sacc., Cercospora armoraciae Sacc., Cercospora corchori Sawada, Cercospora mercurialis Pass., Cercospora olivascens Sacc., Cercospora violae Sacc.; neotypifications - Cercospora fagopyri N. Nakata & S. Takim., Cercospora sojina Hara.
Alternaria fungi are important plant pathogens. Here, we identified three species new to the Japanese mycoflora: Alternaria celosiae, Alternaria crassa and Alternaria petroselini. We proposed a new name for A. celosiae (E.G. Simmons & Holcomb) Lawrence, Park & Pryor, a later homonym of A. celosiae (Tassi) O. S avul. To characterize these and a fourth morphological taxon, Alternaria alstroemeriae, which was recently added to Japan's mycoflora, an integrated species concept was tested. We determined the host range of each isolate using inoculation tests and analysed its phylogenetic position using sequences of the internal transcribed spacer rDNA. The pathogenicity of our A. alstroemeriae isolate was strictly limited to Alstroemeria sp. (Alstroemeriaceae), but the species was phylogenetically indistinguishable from other small-spored Alternaria. Alternaria celosiae on Celosia argentea var. plumosa (Amaranthaceae) was also pathogenic to Amaranthus tricolor, to Alternanthera paronychioides and weakly to Gomphrena globosa (all Amaranthaceae) and formed a clade with the former Nimbya celosiae. Alternaria crassa on Datura stramonium (Solanaceae) was also pathogenic to Brugmansia 9 candida and Capsicum annuum in Solanaceae, but not to other confamilial plants; phylogenetically it belonged to a clade of large-spored species with filamentous beaks. Morphological similarity, phylogenetic relationship and experimental host range suggested that A. crassa, Alternaria capsici and Alternaria daturicola were conspecific. Alternaria petroselini on Petroselinum crispum (Apiaceae) was pathogenic to five species in the tribe Apieae as well as representatives of Bupleureae, Coriandreae, Seliaeae and Scandiceae in Apiaceae. Both phylogeny and morphology suggested conspecificity between A. petroselini and Alternaria selini.
Molecular signaling pathways linking the hypertrophy after mechanical overloading in vivo have not been identified. Using western blot analysis, immunoprecipitation, and immunohistochemistry, we investigated the effect of the mechanical overloading state on RhoA, serum response factor (SRF), and MyoD in the rat plantaris muscle. Adult male rats (10 weeks of age) were used in this experiment. Compensatory enlargement of the plantaris muscle was induced in one leg of each rat by surgical removal of the ipsilateral soleus and gastrocnemius muscles. In the normal plantaris muscle of rats, slight expression of RhoA and SRF was observed in the quiescent satellite cells possessing CD34 and c-Met. Western blotting using the homogenate of whole muscle clearly showed that mechanical overloading of the plantaris muscle significantly increased the amount of RhoA during 3-6 days postsurgery. Threonine phosphorylation of SRF occurred at 2-4 h after mechanical overloading. The most marked increase in SRF protein was observed in the hypertrophied muscle at 6 days postsurgery. At 2 days postoperation, SRF immunoreactivity was not detected in the proliferating satellite cells possessing bromodeoxyuridine and in the infiltrating macrophages expressing ED1 in the overloaded muscle by surgical removal. The SRF protein was colocalized with RhoA, FAK, and myogenin but not Myf-5 in many mononuclear cells at 6 days of functional overload. At this time, MyoD immunoreactivity was detected in the cytoplasm of mononuclear cells (possibly satellite cellderived myoblasts) possessing SRF protein at the nucleus. These results suggest that the signaling pathway through RhoA-FAK-SRF is important to the differentiation of satellite cells by interacting MyoD and myogenin in the hypertrophied muscle of rats.
To clarify the diversity of plant-parasitic Alternaria species in Japan, diseased samples were collected, and fungal isolates established in culture. We examined 85 isolates representing 23 species distributed in 14 known sections based on conidial morphology and DNA phylogeny. Three species were found to be new, A. cylindrica, A. paragomphrenae and A. triangularis. Furthermore, a lectotype was designated for A. gomphrenae, and epitypes for A. cinerariae, A. gomphrenae, A. iridicola, and A. japonica. Species boundaries of isolates were also clarified by studying phenotypes and determining host ranges. Alternaria gomphrenae and related species in sect. Alternantherae were recognized as distinct species owing to their host specificity. Among the species infecting Apiaceae, the pathogenicity of A. cumini and a novel species, A. triangularis ex Bupleurum, were confirmed as host specific. Another novel species, A. cylindrica, proved to be host specific to Petunia. Alternaria iridicola was recognized as a large-spored species in sect. Alternaria, being host specific to Iris spp. On the other hand, the experimental host ranges of three morphologically and phylogenetically distinct species infecting Brassicaceae (A. brassicae, A. brassicicola, and A. japonica) showed almost no differences. Alternaria brassicicola and A. porri were even found on non-host plants. In general, host ranges of Alternaria species correlated with morphology and molecular phylogeny, and combining these datasets resulted in clearer species boundaries.
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