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Application of the consolidated species concept to Cercospora spp. from Iran.

ABSTRACT: The genus Cercospora includes many important plant pathogenic fungi associated with leaf spot diseases on a wide range of hosts. The mainland of Iran covers various climatic regions with a great biodiversity of vascular plants, and a correspondingly high diversity of cercosporoid fungi. However, most of the cercosporoid species found to date have been identified on the basis of morphological characteristics and there are no cultures that support these identifications. In this study the Consolidated Species Concept was applied to differentiate Cercospora species collected from Iran. A total of 161 Cercospora isolates recovered from 74 host species in northern Iran were studied by molecular phylogenetic analysis. Our results revealed a rich diversity of Cercospora species in northern Iran. Twenty species were identified based on sequence data of five genomic loci (ITS, TEF1-?, actin, calmodulin and histone H3), host, cultural and morphological data. Six novel species, viz. C. convolvulicola, C. conyzae-canadensis, C. cylindracea, C. iranica, C. pseudochenopodii and C. sorghicola, are introduced. The most common taxon was Cercospora cf. flagellaris, which remains an unresolved species complex with a wide host range. New hosts were recorded for previously known Cercospora species, including C. apii, C. armoraciae, C. beticola, C. cf. richardiicola, C. rumicis, Cercospora sp. G and C. zebrina.

SUBMITTER: Bakhshi M

PROVIDER: S-EPMC4510272 | biostudies-literature | 2015 Jun

REPOSITORIES: biostudies-literature

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Application of the consolidated species concept to Cercospora spp. from Iran.

Bakhshi M M Arzanlou M M Babai-Ahari A A Groenewald J Z JZ Braun U U Crous P W PW

Persoonia 20141201

The genus Cercospora includes many important plant pathogenic fungi associated with leaf spot diseases on a wide range of hosts. The mainland of Iran covers various climatic regions with a great biodiversity of vascular plants, and a correspondingly high diversity of cercosporoid fungi. However, most of the cercosporoid species found to date have been identified on the basis of morphological characteristics and there are no cultures that support these identifications. In this study the Consolida ...[more]

PMID: 26240446

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Project description:The genus Cercospora includes many important plant pathogens that are commonly associated with leaf spot diseases on a wide range of cultivated and wild plant species. Due to the lack of useful morphological features and high levels of intraspecific variation, host plant association has long been a decisive criterion for species delimitation in Cercospora. Because several taxa have broader host ranges, reliance on host data in Cercospora taxonomy has proven problematic. Recent studies have revealed multi-gene DNA sequence data to be highly informative for species identification in Cercospora, especially when used in a concatenated alignment. In spite of this approach, however, several species complexes remained unresolved as no single gene proved informative enough to act as DNA barcoding locus for the genus. Therefore, the aims of the present study were firstly to improve species delimitation in the genus Cercospora by testing additional genes and primers on a broad set of species, and secondly to find the best DNA barcoding gene(s) for species delimitation. Novel primers were developed for tub2 and rpb2 to supplement previously published primers for these loci. To this end, 145 Cercospora isolates from the Iranian mycobiota together with 25 additional reference isolates preserved in the Westerdijk Fungal Biodiversity Institute were subjected to an eight-gene (ITS, tef1, actA, cmdA, his3, tub2, rpb2 and gapdh) analysis. Results from this study provided new insights into DNA barcoding in Cercospora, and revealed gapdh to be a promising gene for species delimitation when supplemented with cmdA, tef1 and tub2. The robust eight-gene phylogeny revealed several novel clades within the existing Cercospora species complexes, such as C. apii, C. armoraciae, C. beticola, C. cf. flagellaris and Cercospora sp. G. The C. apii s. lat. isolates are distributed over three clades, namely C. apii s. str., C. plantaginis and C. uwebrauniana sp. nov. The C. armoraciae s. lat. isolates are distributed over two clades, C. armoraciae s. str. and C. bizzozeriana. The C. beticola s. lat. isolates are distributed over two clades, namely C. beticola s. str. and C. gamsiana, which is newly described.

Project description:UNLABELLED: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.

Project description:BackgroundQuery ID="Q1" Text="Graphical abstract: As per journal requirements, graphical abstract is necessary. Kindly check and provide the same."The magnitude of the health problems caused by leishmaniasis has been a major driving factor behind the development and implementation of leishmaniasis control programs by the national authorities in Iran, with a priority for health and environmental management. Such programs are not achievable unless all of the factors leading to the infection, including the parasite's life-cycle, vectors and reservoirs, are recognized. So far in Iran, humans and rodents have been considered the principal reservoirs of Leishmania tropica and Leishmania major, respectively, both associated with cutaneous leishmaniasis (CL), with domestic dogs considered to be the main reservoir for Leishmania infantum, associated with visceral leishmaniasis (VL). The role of other mammals in maintaining the Leishmania parasite has remained unclear. This study aimed to investigate Leishmania infection among livestock in endemic areas of VL and CL in Fars province, southern Iran, using serological and molecular methods.MethodsBlood samples from 181 clinically healthy livestock, including 49 sheep, 114 goats, 16 cattle and two donkeys, were screened to detect Leishmania DNA and anti-Leishmania antibodies using qPCR (quantitative PCR) and the direct agglutination test (DAT), respectively. Four qPCR-positive samples were amplified using the internal transcribed spacer one (ITS1) primers in conventional PCR and sent for directional sequencing.ResultsOf the 181 livestock tested, 51 (28.2%) were infected with Leishmania, using serological and molecular methods. Anti-Leishmania antibodies were detected in 70 (38.7%) (95% confidence interval [CI]: 31.5-46.2) and Leishmania DNA in 93 (51.4%) (95% CI: 43.9-58.9) livestock. The identified Leishmania spp. were L. infantum and L. major.ConclusionsThe findings of the present study show a relatively high prevalence of Leishmania infection among livestock in endemic areas of the disease, in Fars province, southern Iran. Given the large population of this group of animals and the fact that they live in the vicinity of the main reservoirs of the disease and vectors, it seems that sand flies regularly bite these animals. Further studies are needed to determine the role of livestock in the parasite's life-cycle and the epidemiology of Leishmania infection.

Project description:Diseases of soybean caused by Cercospora spp. are endemic throughout the world's soybean production regions. Species diversity in the genus Cercospora has been underestimated due to overdependence on morphological characteristics, symptoms, and host associations. Currently, only two species (Cercospora kikuchii and C. sojina) are recognized to infect soybean; C. kikuchii causes Cercospora leaf blight (CLB) and purple seed stain (PSS), whereas C. sojina causes frogeye leaf spot. To assess cryptic speciation among pathogens causing CLB and PSS, phylogenetic and phylogeographic analyses were performed with isolates from the top three soybean producing countries (USA, Brazil, and Argentina; collectively accounting for ~80% of global production). Eight nuclear genes and one mitochondrial gene were partially sequenced and analyzed. Additionally, amino acid substitutions conferring fungicide resistance were surveyed, and the production of cercosporin (a polyketide toxin produced by many Cercospora spp.) was assessed. From these analyses, the long-held assumption of C. kikuchii as the single causal agent of CLB and PSS was rejected experimentally. Four cercosporin-producing lineages were uncovered with origins (about 1 Mya) predicted to predate agriculture. Some of the Cercospora spp. newly associated with CLB and PSS appear to represent undescribed species; others were not previously reported to infect soybeans. Lineage 1, which contained the ex-type strain of C. kikuchii, was monophyletic and occurred in Argentina and Brazil. In contrast, lineages 2 and 3 were polyphyletic and contained wide-host range species complexes. Lineage 4 was monophyletic, thrived in Argentina and the USA, and included the generalist Cercospora cf. flagellaris. Interlineage recombination was detected, along with a high frequency of mutations linked to fungicide resistance in lineages 2 and 3. These findings point to cryptic Cercospora species as underappreciated global considerations for soybean production and phytosanitary vigilance, and urge a reassessment of host-specificity as a diagnostic tool for Cercospora.

Dataset Information

Application of the consolidated species concept to Cercospora spp. from Iran.

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Application of the consolidated species concept to Cercospora spp. from Iran.

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