Species Of Ravenelia Research Articles

Raveneliopsis, a new genus of ravenelioid rust fungi on Cenostigma (Caesalpinioideae) from the Brazilian Cerrado and Caatinga

ABSTRACT 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.

Ravenelia species (Pucciniales) newly found in Thailand with their additional host and life cycle stage

Three poorly known species of Ravenelia with limited geographic distribution and one widespread species parasitizing leguminous trees (Fabaceae) were newly found in Thailand. Ravenelia odoratissimae occurred on Albizia odoratissima ; R. ornata on Abrus pulchellus, Ab. precatorius , and Abrus sp.; R. parasnathii on Acacia comosa and an unidentified Acacia species; and R. tandonii on Acacia catechu . Acacia comosa is a new host for R. parasnathii . Detailed morphological study revealed that R. odoratissimae produces a uredinial stage in addition to a telial stage in its life cycle. • Four Ravenelia species were newly found in Thailand. • Acacia comosa is a new host plant of Ravenelia parasnathii. • Uredinial stage was newly found in the life cycle of Ravenelia odoratissimae.

The genus Ravenelia (Pucciniales) in South Africa

The genus Ravenelia represents the third largest genus of rust fungi and parasitizes a great number of leguminous shrubs and trees, mainly in the subtropics and tropics. Molecular phylogenetic analyses of this genus using nc 28S rDNA and CO3 sequences are presented with a special focus on South African representatives of Ravenelia. Many of the specimens had been collected by us in recent years, mainly from acacia species of the genera Vachellia and Senegalia. Morphological characters were extensively studied using light microscopy and scanning electron microscopy. The analyses resolved several well-supported phylogenetic groups. By linking these groups to their morphology and life cycle characteristics, it was possible to interpret the outcomes in terms of their evolutionary ecology and biogeography. Several characters previously used to define subgeneric groups within Ravenelia were found to be misleading because of assumed convergent evolution. However, host associations, the ability to induce aecial galls as well as the development of two-layered probasidial cells emerged as useful criteria for inferring monophyletic groups. Six novel Ravenelia species were discovered and described. Furthermore, five species represent new reports for South Africa, species descriptions were emended for two taxa, and a new host report emerged for R. inornata.

Raveneliapiepenbringiae and Raveneliahernandezii, two new rust species on Senegalia (Fabaceae, Mimosoideae) from Panama and Costa Rica.

Two new rust species, Raveneliapiepenbringiae and R.hernandezii (Pucciniales) on Senegalia spp. (Fabaceae) are described from the Neotropics (Panama, Costa Rica). A key to the species on neotropical Senegalia spp. is provided. Molecular phylogenetic analyses based on 28S rDNA sequence data suggest that the representatives of Senegalia rusts distributed in the neotropics evolved independently from species known from South Africa. This is further supported by the teliospore morphology, which is characterised by uniseriate cysts in the neotropical Senegalia rusts and contrasting multiseriate cysts in the paleotropic Ravenelia species that infect this host genus.

Morphology of teliospores of ravenelia sp. On forest trees

The study was conducted to show the morphology of teliospores of Ravenelia sp. This rust infects three different forest trees. These all three trees, Albizia procera, Albizia lebbeck , and Pongamia pinnata belong to family Fabaceae . Rust fungus , Ravenelia clemensae Syd. infects the leaves of Albizia procera and Albizia lebbeck , and the host tree Pongamia pinnata was infected by another species of Ravenelia , which was Ravenelia hobsoni . The rust infection starts in the month of September under favorable environmental conditions, when the new foliage is produced on the host plants. The present study showed that telial stage of Ravenelia sp . was found on all three host trees while pycnial, aecial and uredial stages were not found in these trees. The morphology of these spores, is described below. The morphological characters of these teliospores were found to be nearly similar to each other.

Revisão taxonômica de algumas espécies de Ravenelia em leguminosas do Cerrado brasileiro

Oito espécies de Ravenelia descritas anteriormente foram revisadas e acrescentadas ilustrações inéditas das características morfológicas de alguns desses fungos causadores de ferrugem em Leguminosae. As espécies de Ravenelia estudadas foram: Ravenelia bezerrae sobre Enterolobium ellipticum ; R. densifera sobre Senna silvestris; R. dieteliana sobre Calliandra dysantha. var. dysantha; R. geminipora sobre Platymenia reticulata; R. lonchocarpi sobre Lonchocarpus campestris; R. mimosae-sensitivae sobre Mimosa radula var. imbricata; R. pileolarioides sobre Caesalpinia pyramydales e R. santos-costae, sobre Calliandra dysantha.

The genus Ravenelia in Argentina

A comprehensive account of the 18 species of Ravenelia from Argentina is presented. Each species is described and illustrated. A key to the species of Ravenelia from Argentina is provided based on micromorphology. Ravenelia echinata var. ectypa and R. macrocarpa are recorded for the first time from Argentina. The name Ravenelia argentinensis was determined to belong to an anamorph, therefore the teleomorph is described as a new species, R. argentinica sp. nov. Several new anamorph/teleomorph connections were made. Names and synonyms for teleomorphs and anamorphs are listed for all species.

New Ravenelia species on leguminous hosts from the Brazilian Cerrado

Four new Ravenelia species were described on native leguminous hosts from the Brazilian Cerrado, as follows: Ravenelia cerradensis sp. nov., R. chapadensis sp. nov., R. mineirosensis sp. nov. and R. emaensis sp. nov. on Chamaecrista clausenii var. cyclophylla, Chamaecriista conferta var. virgata, Anadenanthera colubrina var. colubrina, and on Anadenanthera sp., respectively.

Morphology of haustoria of Ravenelia and Kernkampella spp.

The haustorial morphology of 21 Ravenelia species, two Kernkampella species, and four leguminicolous Uredo and Uraecium species which are probably related to Ravenelia, was investigated by light microscopy. Three different kinds of interaction could be found: (1) species with haustorial complexes comprising dikaryotic haustoria and intracellular hyphae. These species showed strictly intracellular growth of the parasitic mycelium. (2) Species with only dikaryotic haustoria, and (3) species with only intracellular hyphae or monokaryotic haustoria. Complexes of dikaryotic haustoria and intracellular hyphae were found in 17 of the investigated Ravenelia species and three Uredo species. Three Ravenelia species revealed dikaryotic haustoria, and Ravenelia lonchocarpicola had only intracellular hyphae. Complexes of dikaryotic haustoria and intracellular hyphae are probably the prevalent type of parasitic interaction in Ravenelia. The investigated Kernkampella species revealed dikaryotic haustoria.

Notes on two Indian species of Ravenelia

The spermogonial and aecial stages of Ravenelia evansii are described from recently collected material of Acacia arabica in India. Ravenelia deformis is discussed and referred to Uredo .

A Study of Three African Species of Ravenelia on Cassia

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A Study of Three African Species of Ravenelia on Cassia

A Study of Three African Species of Ravenelia on Cassia

Development of telial head in Ravenelia species

Development and cytology of the telial head in Ravenelia sessilis Berkeley, R. taslimii Mundkurs and R. ornata Sydow are traced in the ontogenic sequence. The species parasitic on leguminous hosts show some variations among themselves in the development of the telial heads and from those parasitizing euphorbiaceous hosts.

Notes on Brazilian Species of Ravenelia

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Notes on Brazilian Species of Ravenelia

Notes on Brazilian Species of Ravenelia

Studies of Mexican Species of Ravenelia

Studies of Mexican Species of Ravenelia

Morphology of Chromosomes in Ravenelia Species

The present study reports the haploid chromosome complement of four species of Ravenelia. Earlier cytological studies have pertained mainly to species of Coleosporium (3, 5), Puccinia (6), Sphenospora (4) and Scopella (7), but the morphological details of chromosomes have not been described precisely. Teliospores were germinated on slides as described by Thirumalachar et al. (9, 10), fixed in Carnoy's fluid (30 ml acetic acid: 30 ml chloroform: 40 ml rectified spirit), and stored in 70% alcohol or passed through the alcohol grades, mordanted, washed and stained with 0.5% acetocarmine (8). The haploid complements of chromosomes were confirmed by the analysis of numerous preparations. Diakinesis quickly merges into metaphase. The chromosomes are thus arranged on the equatorial plate. The nuclear membrane and the nucleolus disappear while the spindle orients parallel to the vertical axis of the basidium. Astral rays are not discernible. Chromosome complements have been determined at metaphase I with confirmation at metaphase II of the meiotic division and in the mitotic division in the basidiospores. The chromosome complement is 8 for R. taslimii Mundk., 6 for R. breyniae Sydow, and 5 for R. hobsonii Cke. and R. emblicae Sydow (TABLE I). In each species, chromosome 1 is distinct from others both in size and shape, being relatively larger. Chromosomes 2, 3 and occasionally 4 resemble each other or chromosome 2 follows the morphological pattern of chromosome 1 rather than 3. Similarly, chromosome 3 resembles chromosome 4 except the size. Variation in morphology occurs among the chromosomes. The individual chromosomes of one species bear little resemblance with those of another species (FIG. 1). a er, K. B., and C. Thom. 1 49. A manual of th Pen cillia. The Wililkins Co., Baltimore. 875 p. a s an, S. A. 1927. Principles of soil micr biology. Bailliere, Tindall, ox, London. 897 p. 205

Cytology and Developmental Morphology of Kernkampella Breyniae-Patentis and Ravenelia Hobsoni

SUMMARY Cytological work on Kernkampella breyniae-patentis and Ravenelia hobsoni was undertaken to find out the relationship between the two genera. It was found the two genera are not related. Development and formation of the teliospore heads, epipatella, germ pores of the teliospores, formation of the pendulous individual cystidial cells of K. breyniae-patentis and hygroscopic cells of R. hobsoni, development of urediospores, and nuclear morphology of K. breyniae-patentis and R. hobsoni are explained. A new genus, Kernkampella, was recently described based on two species of Ravenelia, R. breyniae-patentis and R. breyniae (Rajendren, 1970). The present paper explains the developmental morphology, cellular mechanics of the teliospore wall, germ pores, cystidia, urediospore development, pathogenicity and nuclear morphology of Kernkampella breyniae-patentis and Ravenelia hobsoni. MATERIALS AND METHODS

Studies of North American Species of Ravenelia

This paper presents a taxonomic study of 9 species of Ravenelia occurring on Cassia, Mimosa and Brongniartia in North America. Ravenelia fragrans Long, R. mimosae-sensitivae P. Henn., R. mesillana Ell. & Barth. and R. arthuri Long are redescribed. R. miinosae-albidae Diet., R. mimosae-caeruleae Diet. and R. mimosicola Arth. are reduced to synonymy with R. mimosae-sensitivae, and R. cassiae-covesii Long & Goodd. is reduced to synonymy with R. mesillana. This paper also describes a new species of Ravenelia on Brongniartia sp. from Sinaloa, Mexico and a new variety of R. fragrans. Most of the specimens examined during this study were obtained from the Arthur Herbarium. Purdue University, and included material recently collected by Dr. G. B. Cummins in the southwestern United States and Mexico.

Studies of North American Species of Ravenelia

Studies of North American Species of Ravenelia