RESUMO
Fusarium species are well known for their abundance, diversity and cosmopolitan life style. Many members of the genus Fusarium are associated with plant hosts, either as plant pathogens, secondary invaders, saprotrophs, and/or endophytes. We previously studied the diversity of Fusarium species in the Fusarium oxysporum species complex (FOSC) associated with Fusarium wilt of banana in Indonesia. In that study, several Fusarium species not belonging to the FOSC were found to be associated with Fusarium wilt of banana. These Fusarium isolates belonged to three Fusarium species complexes, which included the Fusarium fujikuroi species complex (FFSC), Fusarium incarnatum-equiseti species complex (FIESC) and the Fusarium sambucinum species complex (FSSC). Using a multi-gene phylogeny that included partial fragments of the beta-tubulin (tub), calmodulin (cmdA), translation elongation factor 1-alpha (tef1), the internal transcribed spacer region of the rDNA (ITS), the large subunit of the rDNA (LSU), plus the RNA polymerase II large subunit (rpb1) and second largest subunit (rpb2) genes, we were able to identify and characterise several of these as new Fusarium species in the respective species complexes identified in this study.
RESUMO
The fern flora of the world (Pteridophyta) has direct evolutionary links with the earliest vascular plants that appeared in the late Devonian. Knowing the mycobiota associated to this group of plants is critical for a full understanding of the Fungi. Nevertheless, perhaps because of the minor economic significance of ferns, this niche remains relatively neglected by mycologists. Cercosporoid fungi represent a large assemblage of fungi belonging to the Mycosphaerellaceae and Teratosphaeriaceae (Ascomycota) having cercospora-like asexual morphs. They are well-known pathogens of many important crops, occurring on a wide host range. Here, the results of a taxonomic study of cercosporoid fungi collected on ferns in Brazil are presented. Specimens were obtained from most Brazilian regions and collected over a 7-yr period (2009-2015). Forty-three isolates of cercosporoid and mycosphaerella-like species, collected from 18 host species, representing 201 localities, were studied. This resulted in a total of 21 frond-spotting taxa, which were identified based on morphology, ecology and sequence data of five genomic loci (actin, calmodulin, ITS, LSU and partial translation elongation factor 1-α). One novel genus (Clypeosphaerella) and 15 novel species (Cercospora samambaiae, Clypeosphaerella sticheri, Neoceratosperma alsophilae, N. cyatheae, Paramycosphaerella blechni, Pa. cyatheae, Pa. dicranopteridis-flexuosae, Pa. sticheri, Phaeophleospora pteridivora, Pseudocercospora brackenicola, Ps. paranaensis, Ps. serpocaulonicola, Ps. trichogena, Xenomycosphaerella diplazii and Zasmidium cyatheae) are introduced. Furthermore, 11 new combinations (Clypeosphaerella quasiparkii, Neoceratosperma yunnanensis, Paramycosphaerella aerohyalinosporum, Pa. dicranopteridis, Pa. gleicheniae, Pa. irregularis, Pa. madeirensis, Pa. nabiacense, Pa. parkii, Pa. pseudomarksii and Pa. vietnamensis) are proposed. Finally, nine new host associations are recorded for the following known fungal species: Cercospora coniogrammes, Cercospora sp. Q, Ps. abacopteridicola, Ps. lygodiicola and Ps. thelypteridis.
RESUMO
Although the genus Pseudocercospora has a worldwide distribution, it is especially diverse in tropical and subtropical countries. Species of this genus are associated with a wide range of plant species, including several economically relevant hosts. Preliminary studies of cercosporoid fungi from Brazil allocated most taxa to Cercospora, but with the progressive refinement of the taxonomy of cercosporoid fungi, many species were relocated to or described in Pseudocercospora. Initially, species identification relied mostly on morphological features, and thus no cultures were preserved for later phylogenetic comparisons. In this study, a total of 27 Pseudocercospora spp. were collected, cultured, and subjected to a multigene analysis. Four genomic regions (LSU, ITS, tef1 and actA) were amplified and sequenced. A multigene Bayesian analysis was performed on the combined ITS, actA and tef1 sequence alignment. Our results based on DNA phylogeny, integrated with ecology, morphology and cultural characteristics revealed a rich diversity of Pseudocercospora species in Brazil. Twelve taxa were newly described, namely P. aeschynomenicola, P. diplusodonii, P. emmotunicola, P. manihotii, P. perae, P. planaltinensis, P. pothomorphes, P. sennae-multijugae, P. solani-pseudocapsicicola, P. vassobiae, P. wulffiae and P. xylopiae. Additionally, eight epitype specimens were designated, three species newly reported, and several new host records linked to known Pseudocercospora spp.
RESUMO
Pyricularia oryzae is a species complex that causes blast disease on more than 50 species of poaceous plants. Pyricularia oryzae has a worldwide distribution as a rice pathogen and in the last 30 years emerged as an important wheat pathogen in southern Brazil. We conducted phylogenetic analyses using 10 housekeeping loci for 128 isolates of P. oryzae sampled from sympatric populations of wheat, rice, and grasses growing in or near wheat fields. Phylogenetic analyses grouped the isolates into three major clades. Clade 1 comprised isolates associated only with rice and corresponds to the previously described rice blast pathogen P. oryzae pathotype Oryza (PoO). Clade 2 comprised isolates associated almost exclusively with wheat and corresponds to the previously described wheat blast pathogen P. oryzae pathotype Triticum (PoT). Clade 3 contained isolates obtained from wheat as well as other Poaceae hosts. We found that Clade 3 is distinct from P. oryzae and represents a new species, Pyricularia graminis-tritici (Pgt). No morphological differences were observed among these species, but a distinctive pathogenicity spectrum was observed. Pgt and PoT were pathogenic and highly aggressive on Triticum aestivum (wheat), Hordeum vulgare (barley), Urochloa brizantha (signal grass), and Avena sativa (oats). PoO was highly virulent on the original rice host (Oryza sativa), and also on wheat, barley, and oats, but not on signal grass. We conclude that blast disease on wheat and its associated Poaceae hosts in Brazil is caused by multiple Pyricularia species. Pyricularia graminis-tritici was recently found causing wheat blast in Bangladesh. This indicates that P. graminis-tritici represents a serious threat to wheat cultivation globally.
RESUMO
Members of the Asterinaceae and Parmulariaceae are obligate biotrophic fungi with a pantropical distribution that grow in direct association with living plant tissues and produce external ascomata and bitunicate asci. These fungi are poorly known, with limited information about their taxonomic position in the Dothideomycetes. Much of what is known is conjectural and based on observation of morphological characters. An assessment of the phylogenetic position of the Asterinaceae and Parmulariaceae is provided based on a phylogenetic analysis of the nrDNA operon (ITS) and the large subunit rDNA (LSU) sequence data obtained from fresh material of selected species collected in Brazil. Three key species were included and epitypified, namely Asterina melastomatis, which is the type species for the type genus of the Asterinaceae; Prillieuxina baccharidincola (Asterinaceae); and Parmularia styracis, which is the type species for the type genus of the Parmulariaceae. An LSU rDNA phylogenetic analysis was performed indicating the correct phylogenetic placement of the Asterinales within the Dothideomycetes. From this initial analysis it is clear that the Parmulariaceae as currently circumscribed is polyphyletic, and that the Asterinaceae and Parmulariaceae are related, which justifies the maintenance of the order Asterinales. Asterotexis cucurbitacearum is recognised as distinct from other Dothideomycetes and placed in the newly proposed family and order (Asterotexiaceae, Asterotexiales), while the higher order phylogeny of Inocyclus angularis remains unresolved. Additionally, Lembosia abaxialis is introduced as a novel species and the phylogenetic placement of the genera Batistinula and Prillieuxina is clarified.
RESUMO
Species in the genus Calonectria (Hypocreales) represent an important group of plant pathogenic fungi that cause serious losses to plant crops in tropical and subtropical climates. Calonectria leaf blight is currently one of the main impediments to Eucalyptus cultivation in Brazil, and various species of Calonectria have been associated with this disease. Since most previous identifications were solely based on morphological characters, much of the published literature needs to be re-evaluated. The aim of this study was thus to identify and determine the phylogenetic relationships among species that occur in the Eucalyptus growing regions of Brazil by using partial sequences of the ß-tubulin, calmodulin, translation elongation factor 1-α and histone H3 gene regions. Based on extensive collections from soil and infected eucalypt leaf samples from plantations, phylogenetic inference revealed the Ca. pteridis complex to be the most common species complex present in Eucalyptus plantations in Brazil. By elucidating taxa in the Ca. pteridis, Ca. cylindrospora and Ca. candelabra species complexes, 20 novel Calonectria species were identified, and a new name in Calonectria provided for Cylindrocladium macrosporum as Ca. pseudopteridis.
RESUMO
Diaporthe (Phomopsis) species have often been reported as plant pathogens, non-pathogenic endophytes or saprobes, commonly isolated from a wide range of hosts. The primary aim of the present study was to resolve the taxonomy and phylogeny of a large collection of Diaporthe species occurring on diverse hosts, either as pathogens, saprobes, or as harmless endophytes. In the present study we investigated 243 isolates using multilocus DNA sequence data. Analyses of the rDNA internal transcribed spacer (ITS1, 5.8S, ITS2) region, and partial translation elongation factor 1-alpha (TEF1), beta-tubulin (TUB), histone H3 (HIS) and calmodulin (CAL) genes resolved 95 clades. Fifteen new species are described, namely Diaporthe arengae, D. brasiliensis, D. endophytica, D. hongkongensis, D. inconspicua, D. infecunda, D. mayteni, D. neoarctii, D. oxe, D. paranensis, D. pseudomangiferae, D. pseudophoenicicola, D. raonikayaporum, D. schini and D. terebinthifolii. A further 14 new combinations are introduced in Diaporthe, and D. anacardii is epitypified. Although species of Diaporthe have in the past chiefly been distinguished based on host association, results of this study confirm several taxa to have wide host ranges, suggesting that they move freely among hosts, frequently co-colonising diseased or dead tissue. In contrast, some plant pathogenic and endophytic taxa appear to be strictly host specific. Given this diverse ecological behaviour among members of Diaporthe, future species descriptions lacking molecular data (at least ITS and HIS or TUB) should be strongly discouraged.