RESUMO
Hemileia vastatrix, causal agent of coffee leaf rust (CLR), is an aggressive pathogen of coffee plants worldwide. Conventional fungicides play a major role in the suppression of this disease, but a recent shift toward eco-friendly farming practices has occurred and additional novel, effective, and sustainable strategies for CLR control are needed. Naturally occurring fungal antagonists could be well-positioned to meet this demand, but these fungi need to be isolated and tested for efficacy to identify organisms with potential. In this study, a survey of fungi associated with CLR lesions in four districts of Hawai'i Island, HI, USA (Kona, Ka'u, Hamakua, and Hilo) was conducted. Coffee leaves infected with CLR were collected from 22 locations and over 600 lesions were plated on ½ APDA and CTC 4T media. DNA was extracted from purified isolates and the internal transcribed spacer region (ITS) was sequenced and analyzed by BLASTn. In total, 194 isolates comprising 50 taxa were recovered. Several of the genera are known antagonists of CLR or other plant pathogens, including Simplicillium, Akanthomyces, Cladosporium, Fusarium, and Clonostachys. The wide diversity of fungi associated with CLR lesions provide a wealth of possibilities for identifying potential CLR antagonists that could serve as a valuable tool for coffee farmers as part of an integrated pest management plan.
Assuntos
Coffea , Doenças das Plantas , Folhas de Planta , Coffea/microbiologia , Havaí , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , Folhas de Planta/microbiologia , Fungos/classificação , Fungos/isolamento & purificação , Fungos/genética , Fungos/efeitos dos fármacos , Basidiomycota/isolamento & purificação , Basidiomycota/genética , Basidiomycota/classificação , AntibioseRESUMO
In 1895 and 2001, rust fungi affecting Licania trees (Chrysobalanchaceae) in Brazil were described as Uredo licaniae by Hennings in the state of Goiás and as Phakopsora tomentosae by Ferreira et al. in the state of Amazonas, respectively. Recently, a Licania rust fungus collected close to the Amazonian type location sharing symptoms with the former two species was subjected to morphological examinations and molecular phylogenetic analyses using 28S nuc rDNA (ITS2-28S) and cytochrome c oxidase subunit III (CO3) gene sequences. Since the original type specimen of Ph. tomentosae is considered lost, we carefully reviewed the type description and questioned the identity of the telium, which justified the description of the fungus as a Phakopsora species. Furthermore, the additional revision of the type material described by Hennings revealed that Ph. tomentosae is a synonym of U. licaniae. Based on the morphological examinations, disease symptoms, and shared hosts, we concluded that the newly collected material is conspecific with U. licaniae. However, the phylogenetic analyses rejected allocation in Phakopsora and instead assigned the Licania rust fungus in a sister relationship with Austropuccinia psidii (Sphaerophragmiaceae), the causal agent of the globally invasive myrtle rust pathogen. We therefore favored a recombination of U. licaniae (syn. Ph. tomentosae) into Austropuccinia and proposed the new name Austropuccina licaniae for the second species now identified for this genus. The fungus shares conspicuous symptoms with A. psidii, causing often severe infections of growing leaves and shoots that lead to leaf necrosis, leaf shedding, and eventually to the dieback of entire shoots. In view of the very similar symptoms of its aggressively invasive sister species, we briefly discuss the current state of knowledge about A. licaniae and the potential risks, and the opportunity of its identification.
Assuntos
Basidiomycota , DNA Fúngico , Filogenia , Doenças das Plantas , Basidiomycota/genética , Basidiomycota/classificação , Basidiomycota/isolamento & purificação , Doenças das Plantas/microbiologia , DNA Fúngico/genética , Brasil , Análise de Sequência de DNA , RNA Ribossômico 28S/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Árvores/microbiologiaRESUMO
Two Cerrado rust fungi, Phakopsora rossmaniae and Aplopsora hennenii, described in 1993 and 1995 and originally assigned to families Phakopsoraceae and Ochropsoraceae, respectively, were subjected to molecular phylogenetic analyses using fragments of the nuc 28S and 18S rDNA and mitochondrial cytochrome c oxidase subunit 3 (CO3) gene. Although both taxa were morphologically well placed in their original genera, they were shown to belong in a strongly supported new lineage within the Raveneliineae distant from the Phakopsoraceae and Ochropsoraceae. Therefore, we properly treated this lineage as the new genus Cerradopsora now harboring C. rossmaniae (type species) and C. hennenii. However, this novel phakopsoroid genus remains in uncertain familial position without support to be included in any of the families that share space within the Raveneliineae.
Assuntos
Basidiomycota , Humanos , Filogenia , DNA Fúngico/genética , Basidiomycota/genética , DNA Ribossômico/genéticaRESUMO
The multicellular discoid convex teliospore heads represent a prominent generic feature of the genus Ravenelia. However, recent molecular phylogenetic work has shown that this is a convergent trait, and that this genus does not represent a natural group. In 2000, a rust fungus infecting the Caesalpinioid species Cenostigma macrophyllum (= C. gardnerianum) was described as Ravenelia cenostigmatis. This species shows some rare features, such as an extra layer of sterile cells between the cysts and the fertile teliospores, spirally ornamented urediniospores, as well as strongly incurved paraphyses giving the telia and uredinia a basket-like appearance. Using freshly collected specimens of Rav. cenostigmatis and Rav. spiralis on C. macrophyllum, our phylogenetic analyses based on the nuc 28S, nuc 18S, and mt CO3 (cytochrome c oxidase subunit 3) gene sequences demonstrated that these two rust fungi belong in a lineage within the Raveneliineae that is distinct from Ravenelia s. str. Besides proposing their recombination into the new genus Raveneliopsis (type species R. cenostigmatis) and briefly discussing their potentially close phylogenetic affiliations, we suggest that five other Ravenelia species that are morphologically and ecologically close to the type species of Raveneliopsis, i.e., Rav. corbula, Rav. corbuloides, Rav. parahybana, Rav. pileolarioides, and Rav. Striatiformis, may be recombined pending new collections and confirmation through molecular phylogenetic analyses.
Assuntos
Basidiomycota , Fabaceae , Brasil , Filogenia , Basidiomycota/genéticaRESUMO
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.
Assuntos
Filogenia , BrasilRESUMO
Blackberry (Rubus spp.) is a shrub plant of the Rosaceae, which fruits are used for fresh markets or processing. Blackberry cultivation has increased in Brazil and has turned into an alternative for family farmers. Among the significant diseases that can occur in plantations, there is rust, caused by phytopathogenic fungus species: Gymnoconia nitens (orange rust), Kuehneola uredinis (cane and leaf rust) and Phragmidium violaceum (blackberry rust). This research project was conducted to identify the fungi specie causative of rust occurred on experimental blackberry fields, in Diamantina, state of Minas Gerais, Brazil. Infected blackberry leaves with symptoms of rust fungi and full spores yellow were collected. Infection was limited to undersurfaces of the leaves and reddening occurred on corresponding upper areas. No stem or fruit infection occurred on the infected plants. Morphological analyzes of the microstructures (sorus and spores) were carried out under optical microscopy and scanning electron microscopy (SEM). It was observed uredinia with urediniospores uniformly echinulate golden-yellow and telia obtain with teliospores smooth hyaline, mostly four celled and with a short rounded apical papilla. The rust was identified as Kuehneola uredinis (Link) Arthur. This is the first record for Brazil. Morphological descriptions, illustrations of the microstructures, examined material, geographic distribution and taxonomic comments are provided for this species.
RESUMO
RESUMEN Este trabajo tiene como objetivo presentar los Pucciniales encontrados en páramos de Antioquia sobre la familia Cyperaceae. Fueron realizadas colecciones de plantas parasitadas por Pucciniales en páramos del departamento de Antioquia en altitudes desde los 2800 hasta 4050 m s.n.m.; de los 136 materiales colectados, un total de 18 correspondieron a la familia Cyperaceae. Los estados espóricos se observaron bajo el estereomicroscopio permitiendo tener información sobre los soros y a partir de allí se realizaron micropreparados en lactoglicerina mediante raspados o cortes a mano alzada, se hicieron 40 mediciones de cada una de las estructuras encontradas al microscopio y con una cámara digital acoplada a este se tomaron las microfotografías. Entre los resultados obtenidos destacan la descripción de la nueva especie Puccinia sonsonensis; el primer registro para Colombia de Puccinia caricina, Puccinia dioicae y Puccinia cephalotes y se registran por primera vez especies del género Carex parasitadas por roya en Colombia. Los resultados proveen un argumento adicional sobre la urgencia de preservación y continuar con los estudios en estas áreas.
ABSTRACT This paper aims to present the Pucciniales found in paramos of Antioquia on the Cyperaceae family. Collections were made of parasitized plants by Pucciniales in páramos of Antioquia Department with altitudes from 2800 to 4050 masl.; of the 136 collected materials, a total of 18 belonged to the Cyperaceae family. The spore states were observed under the stereomicroscope to have information about sori and from there micropreparations were made in lactoglycerin through free-hand sections and scrapings, 40 measurements were made of each of the structures found under the microscope and images were taken with a digital camera coupled. Results obtained include the description of the new species Puccinia sonsonensis; the first registration for Colombia of Puccinia caricina, Puccinia dioicae and Puccinia cephalotes, and first time record of species of the genus Carex parasitized by rust in Colombia. The results provide a additional argument the urgency of preservation and continuous study for such areas.