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A–E. Uromyces hawksworthii (UB Mycol. Col. 22875): A. Circular to irregular dark brown telia on the adaxial face. B. Erumpent telium. C. A group of mature teliospores and several long paraphysis-like pedicels. D. Telium seen in SEM. E. Teliospores showing the characteristically pitted wall in SEM. Bars: A = 1 cm, B = 2 mm, C = 10 µm, D = 100 µm, E = 5 µm.
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The sexual morph of Aecidium goyazense collected in the Brazilian Cerrado was morphologically characterized by light microscopy and SEM, and shown to be a species of Uromyces, for which the name Uromyces hawksworthii nom. nov. is introduced, and designated as its
epitype. This is the second Uromyces species known to infect the tropical genus Phthir...
Citations
... However, inoculation can be influenced by such factors as overwintering teliospores, maturity of basidiospores, and plant growth conditions. Thus, molecular systematics has gradually come to be used in the confirmation of rust life cycles, such as for the species of Gymnosporangium, Puccinia, and Uromyces (Anikster et al. 2004;Cao et al. 2017;Souza et al. 2015;Zhao et al. 2016). In the present study, molecular systematics has been used to clarify the life cycle of G. gansuense and G. granulatosporum. ...
A serious Juniperus rigida rust disease was found in Gansu Province, China. The disease incidence is approximately 80-90%. We also found rust disease on both Cotoneaster multiflorus and Sorbus in the same location. Two novel Gymnosporangium species were identified from the infected plants. Based on morphological observations and phylogenetic analyses, we describe the two new taxa as G. gansuense and G. granulatosporum. We also determined their life cycles. Moreover, this study documented a novel aeciospore surface structure with two different surface types on one aeciospore. We describe it here as "granular."
... A second species of the rare genus Skierka (S. divinopolensis) was described on Matayba guianensis (Sapindaceae) from the Cerrado (DIANESE et al. 1993d, HENNEN et al. 2005. Another highlight was the complete description of the first Uromyces species (U. hawksworthii) from the Cerrado infecting a plant hemiparasite, Phthirusa stelis (Lotanthaceae) (SOUZA et al. 2015), previously described in its asexual form (Aecidium goyazense) by Hennings (1895). Dianese et al. (1993d), surveying the rust fungi on Fabaceae, described initially two new Ravenelia species (R. bezerrae, and R. santos-costae), and later R. cerradensis, R. chapadensis, R. emaensis, andR. ...
In this review, we present an historic account of the work on the diversity of fungi associated with plants of the Cerrado Biome, including an overview of the studies carried out by the research group of the Mycological Collection connected to the Herbarium UB (Universidade de Brasília), and the rust fungi in Herbarium IBI (Instituto Biológico, São Paulo). The contributions to Cerrado mycology from the early 19th century to the present days were highlighted. Illustrative maps were included to show the geographical distribution of the main fungal groups, associated with native plants of the Cerrado, belonging to the five predominant orders: Pucciniales (rust fungi), Phyllachorales (tar-spot fungi), Capnodiales (cercosporoid fungi: Family Mycosphaerellaceae), as well as Meliolales and Asterinales (black mildews).
... The genus Uromyces (Pucciniales, Basidiomycota) comprises more than 600 species of rust fungi worldwide, parasitizing monocotyledon and dicotyledon hosts (Kirk et al. 2008;McTaggart et al. 2014). In the case of Brazil, more than 100 species have been documented (Maia et al. 2015;Souza et al. 2015), infecting economically important crops such as common bean (Uromyces appendiculatus and Uromyces fabae), pea (Uromyces pisi) and beets (Uromyces betae; Farr and Rossman 2017). ...
The commonweed Euphorbia hirta (Euphorbiaceae) grows widely across tropical and subtropical regions. In this study, plants infected by an Uromyces species displayed charac- teristic rust pustules delimited by a necrotic band with a reddish- brown border. Observation of leaf tissues revealed 74% of le- sions encircled by a row of dark brown setose acervuli, present exclusively within the necrotic area. Acervuli were never ob- served in the absence of Uromyces pustules. Isolation from healthy leaf tissues revealed the fungus to be endophytic. Morphological and molecular characterization confirmed Uromyces euphorbiae as the pathogen and revealed both the endophyte and the pustule-associated fungus to be members of the Colletotrichum trucatum complex, representing the first re- cord of this fungus on E. hirta. As understanding of the interac- tion between host plants, endophytes and phytopathogens is cur- rently limited, this systemconstitutes a model for investigation of the physiological processes involved in this endophyte- biotrophic pathogen interaction.
... (JACKSON 1927), and A. goyazense HENN. on Phthirusa stelis in Goiás, Brazil (SACCARDO 1899, SYDOW & SYDOW 1924). Recently, SOUZA & al. (2015) reported Uromyces hawksworthii SOUZA, E. S. C, CHAVES, Z. M. C., SOARES, W. R. O., PINHO, D. B. & DI- ANESE, J. C. as replacement name for A. goyazense on Phthirusa stelis (Loranthaceae), based on DNA sequences generated from the ITS and 28S rRNA (LSU) regions of DNA recovered from aeciospores and teliospores. The current study aims to describe and confirm the morphological characteristics of aecial and uredinial/telial stages of the rust fungus on P. stelis by using microscopy (optical and SEM), and to compare both stages by conducting molecular analyses of this rust species on Loranthaceae. ...
... The molecular blasting of the rust fungus with GenBank data, matched that of U. hawksworthii previously deposited in GenBank and registered in Mycobank by SOUZA & al. (2015),, found on Loranthaceae in the Brazilian cerrado. The current research confirms the results found by these authors and furthermore adds the description of the uredinia and urediniospores morphologically and molecularly. ...
Abstract: This study describes Uromyces hawksworthii (Basidiomycota: Pucciniales) on morphological and molecular level. This rust fungus often infects Phthirusa stelis (Loranthaceae), a common hemiparasite on trees in the Brazilian cerrado. The morphology of the rust was evaluated by light and scanning electron microscopy. Partial sequences of the ITS region of rDNA were obtained from both aecial and telial stages using cloning techniques. Morphological features of the aecial stage match the description of Aecidium goyazense Henn., while analysis of urediniospores and teliospores indicates that the correct name for this fungus is Uromyces hawksworthii. Molecular identification and maximum likelihood analysis revealed that this species belongs to the Pucciniaceae, which contains the Puccinia/Uromyces genus complex. Furthermore, four sequences of aeciospores and two of the teliospores showed more than 99% of similarity compared with each other. Morphological and genetic studies confirmed that Uromyces hawksworthii is a macrocyclic autoecious rust fungus, whose aecial stage is A. goyazense, as has already been found by SOUZA & al. 2015.
The genus Cerradoa (type species Cerradoa palmaea) was established in 1978 by Hennen and Ono and named after the Brazilian Cerrado biome. The holotype collected in Planaltina, Federal District, Brazil, belonged to the first rust fungus reported on palms (Arecaceae). For decades, the status of Cerradoa as a distinct genus has been regarded as doubtful, representing a synonym of Edythea (Uropyxidaceae) starting with the second edition of the Illustrated Genera of Rust Fungi in 1983. Our molecular phylogenetic analyses, as well as our morphological investigations, allowed us to reject this synonymy, leading to the reinstatement of Cerradoa within the Pucciniaceae. Cerradoa, together with morphologically similar genera such as the newly established Pseudocerradoa with two species (Ps. paullula and Ps. rhaphidophorae) infecting araceous hosts, the fern rust Desmella, and also P. engleriana, could not be assigned to any of the seven identified major lineages within the Pucciniaceae. Edythea, instead of being maintained as a member of the Uropyxidaceae, was herein placed in Pucciniaceae, shown phylogenetically in close relationship to Cumminsiella mirabilissima, both infecting the Berberidaceae. Additionally, our extensive phylogenetic analyses add guidance for future taxonomic revisions in the highly polyphyletic genus Puccinia and other established taxa within the family Pucciniaceae.
Uromyces is the second-largest plant pathogenic rust genus, is responsible for numerous diseases, and has major effects on both agricultural and non-agricultural plants. The genus is generally characterized by its unicellular teliospores that help to characterize it and distinguish it from another important rust genus, Puccinia. In this study, a global overview of the diversity and distribution of Uromyces is presented based on both online and offline resources. The information obtained was analyzed for numerical and graphical summaries to provide the diversity and distribution of the genus by country and continent. Besides this, broad taxonomical aspects, a brief life cycle, and other comparative aspects on diversity and distribution were also provided. In addition, a phy-logenetic analysis based on the ITS and nLSU DNA sequence data available in GenBank and published literature was performed to examine the intergeneric relationships of Uromyces. The results obtained revealed that the rust genus is found distributed over 150 countries, territories, and occu-pancies of the world on around 647 plant genera belonging to 95 plant families. Phylogenetic studies based on LSU and ITS sequence data revealed that Uromyces species are polyphyletic and require more DNA-based analyses for a better understanding of their taxonomic placement.
Gymnosporangium is a group of plant fungal pathogens that cause rust diseases on many economically important fruit trees. Most Gymnosporangium are heteroecious and demicyclic, producing four morphologically diverse spore stages on two taxonomically unrelated host plants, the Cupressaceae and Rosaceae. The complex life cycle and heteroecism make it difficult to investigate the species within Gymnosporangium. To determine the taxonomy, phylogeny, and species diver- sity of Gymnosporangium in China, a large collection of 672 specimens were analyzed using a combination of morphological observations and phylogenetic analyses. In total, 27 Gymnosporangium species from China are documented here, including 22 known species, one new combination, one new record, and three new species. The study also documents a novel aeciospore surface structure with an irregular surface that is described here as “surfy.”
Gymnosporangium species ( Pucciniaceae , Pucciniales , Basidiomycota ) are the causal agents of cedar-apple rust diseases, which can lead to significant economic losses to apple cultivars. Currently, the genus contains 17 described species that alternate between spermogonial/aecial stages on Malus species and telial stages on Juniperus or Chamaecyparis species, although these have yet to receive a modern systematic treatment. Furthermore, prior studies have shown that Gymnosporangium does not belong to the Pucciniaceae sensu stricto (s.str.), nor is it allied to any currently defined rust family. In this study we examine the phylogenetic placement of the genus Gymnosporangium . We also delineate interspecific boundaries of the Gymnosporangium species on Malus based on phylogenies inferred from concatenated data of rDNA SSU, ITS and LSU and the holomorphic morphology of the entire life cycle. Based on these results, we propose a new family, Gymnosporangiaceae , to accommodate the genus Gymnosporangium , and recognize 22 Gymnosporangium species parasitic on Malus species, of which G. lachrymiforme , G. shennongjiaense , G. spinulosum , G. tiankengense and G. kanas are new. Typification of G. asiaticum , G. fenzelianum , G. juniperi-virginianae , G. libocedri , G. nelsonii , G. nidus-avis and G. yamadae are proposed to stabilize the use of names. Morphological and molecular data from type materials of 14 Gymnosporangium species are provided. Finally, morphological characteristics, host alternation and geographical distribution data are provided for each Gymnosporangium species on Malus .
The common weed Euphorbia hirta (Euphorbiaceae) grows widely across tropical and subtropical regions. In this study, plants infected by an Uromyces species displayed characteristic rust pustules delimited by a necrotic band with a reddish-brown border. Observation of leaf tissues revealed 74% of lesions encircled by a row of dark brown setose acervuli, present exclusively within the necrotic area. Acervuli were never observed in the absence of Uromyces pustules. Isolation from healthy leaf tissues revealed the fungus to be endophytic. Morphological and molecular characterization confirmed Uromyces euphorbiae as the pathogen and revealed both the endophyte and the pustule-associated fungus to be members of the Colletotrichum trucatum complex, representing the first record of this fungus on E. hirta. As understanding of the interaction between host plants, endophytes and phytopathogens is currently limited, this system constitutes a model for investigation of the physiological processes involved in this endophyte-biotrophic pathogen interaction.
