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Shivasia gen. nov. for the Australasian smut Ustilago solida that historically shifted through five different genera.

Lutz M, Vánky K, Piątek M - IMA Fungus (2012)

Bottom Line: Ustilago solida has previously been included in five different genera (Ustilago, Urocystis, Sorosporium, Cintractia, and Tolyposporium), however, molecular analyses revealed that this smut does not belong to any of these genera and represents a distinct ustilaginalean lineage.The description of Shivasia increases the number of endemic smut genera in Australasia to ten.Compared to all other continents the number of endemic smut genera is exceptionally high, which may point at fast evolving characters and/or may be caused by the regional history, including the long-term geographic isolation of Australasia.

View Article: PubMed Central - PubMed

Affiliation: Evolutionäre Ökologie der Pflanzen, Institut für Evolution und Ökologie, University of Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany;

ABSTRACT
The generic position of the enigmatic smut fungus Ustilago solida is evaluated applying molecular phylogenetic analyses using ITS and LSU rDNA sequences as well as light and scanning electron microscopical investigations of several collections of this species. Ustilago solida has previously been included in five different genera (Ustilago, Urocystis, Sorosporium, Cintractia, and Tolyposporium), however, molecular analyses revealed that this smut does not belong to any of these genera and represents a distinct ustilaginalean lineage. The closest known phylogenetic relative of Ustilago solida is Heterotolyposporium lepidospermatis, the type species of the monotypic genus Heterotolyposporium. Both smuts differ considerably in both LSU sequences and in several morphological traits, such as the structure of sori and the characteristics of spore balls. Accordingly, the new genus Shivasia is described to accommodate Ustilago solida. This smut infects different Schoenus species (Cyperaceae) in Australia and New Zealand. The description of Shivasia increases the number of endemic smut genera in Australasia to ten. Compared to all other continents the number of endemic smut genera is exceptionally high, which may point at fast evolving characters and/or may be caused by the regional history, including the long-term geographic isolation of Australasia.

No MeSH data available.


Related in: MedlinePlus

Shivasia solida on Schoenus apogon. A. Embedded, stained, semi-thin section of a sorus (H.U.V. 17649), sh = sporogenous hyphae, sp = spore balls, p = peridium. B. Fungal cells of the peridium covering the sori, formed of thick-walled, sterile hyphae (H.U.V. 15059). C. Spore ball formation in sporogenous fungal layer on the surface of innermost floral organs, in U-shaped pockets, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). D–E. Young spores and spore balls covered by fungal cells of the young peridium, embedded in plastic, sectioned and stained with new fuchsin and cristal violet (H.U.V. 15059). F. Spore balls in different developmental stages, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). G–H. Spore germination in water, at room temperature, in 3–5 days (H.U.V. 15059). Bars: A = 100 μm, B–H = 10 μm.
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Figure 3: Shivasia solida on Schoenus apogon. A. Embedded, stained, semi-thin section of a sorus (H.U.V. 17649), sh = sporogenous hyphae, sp = spore balls, p = peridium. B. Fungal cells of the peridium covering the sori, formed of thick-walled, sterile hyphae (H.U.V. 15059). C. Spore ball formation in sporogenous fungal layer on the surface of innermost floral organs, in U-shaped pockets, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). D–E. Young spores and spore balls covered by fungal cells of the young peridium, embedded in plastic, sectioned and stained with new fuchsin and cristal violet (H.U.V. 15059). F. Spore balls in different developmental stages, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). G–H. Spore germination in water, at room temperature, in 3–5 days (H.U.V. 15059). Bars: A = 100 μm, B–H = 10 μm.

Mentions: Sori (Figs 2–3) in all flowers of an inflorescence, comprising the innermost floral organs, visible between the glumes as black, globose to ovoid bodies, 1–2 mm diam, rarely also on the stems, then fusiform, at first covered by a thick, whitish brown fungal peridium of thick-walled, sterile hyphae that early flakes away exposing the compact mass of spore balls with spores, powdery on the surface. Spore balls (Fig. 4) usually irregular or globoid to ellipsoidal, composed of 2–15 spores, loose but rather permanent, 25–55(−70) × 20–40 μm, reddish brown, enclosed by subhyaline mucilaginous layer. Spores (Fig. 4) subglobose, ovoid, elongate or irregular, flattened on one or two sides, 15–20 × 12–16 μm, yellowish to pale reddish brown; wall uneven, 0.5–1.5 μm thick, smooth to rough, in SEM finely, densely, irregularly verruculose and covered by remnants of the mucilaginous layer which form irregularly warty (pseudo-)ornamentation. Spore balls and spores produced on the surface of host tissues in hyaline, sporogenous fungal layer within radially arranged, U-shaped pockets (Fig. 3C–F). Spore germination (Fig. 3G–H; on water, at room temperature, in 3–5 d) results in long, aseptate basidia on which apically elongated, cylindrical basidiospores are produced that germinate by filaments.


Shivasia gen. nov. for the Australasian smut Ustilago solida that historically shifted through five different genera.

Lutz M, Vánky K, Piątek M - IMA Fungus (2012)

Shivasia solida on Schoenus apogon. A. Embedded, stained, semi-thin section of a sorus (H.U.V. 17649), sh = sporogenous hyphae, sp = spore balls, p = peridium. B. Fungal cells of the peridium covering the sori, formed of thick-walled, sterile hyphae (H.U.V. 15059). C. Spore ball formation in sporogenous fungal layer on the surface of innermost floral organs, in U-shaped pockets, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). D–E. Young spores and spore balls covered by fungal cells of the young peridium, embedded in plastic, sectioned and stained with new fuchsin and cristal violet (H.U.V. 15059). F. Spore balls in different developmental stages, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). G–H. Spore germination in water, at room temperature, in 3–5 days (H.U.V. 15059). Bars: A = 100 μm, B–H = 10 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3539317&req=5

Figure 3: Shivasia solida on Schoenus apogon. A. Embedded, stained, semi-thin section of a sorus (H.U.V. 17649), sh = sporogenous hyphae, sp = spore balls, p = peridium. B. Fungal cells of the peridium covering the sori, formed of thick-walled, sterile hyphae (H.U.V. 15059). C. Spore ball formation in sporogenous fungal layer on the surface of innermost floral organs, in U-shaped pockets, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). D–E. Young spores and spore balls covered by fungal cells of the young peridium, embedded in plastic, sectioned and stained with new fuchsin and cristal violet (H.U.V. 15059). F. Spore balls in different developmental stages, hand sectioned, stained with cotton blue in lactophenol (H.U.V. 15059). G–H. Spore germination in water, at room temperature, in 3–5 days (H.U.V. 15059). Bars: A = 100 μm, B–H = 10 μm.
Mentions: Sori (Figs 2–3) in all flowers of an inflorescence, comprising the innermost floral organs, visible between the glumes as black, globose to ovoid bodies, 1–2 mm diam, rarely also on the stems, then fusiform, at first covered by a thick, whitish brown fungal peridium of thick-walled, sterile hyphae that early flakes away exposing the compact mass of spore balls with spores, powdery on the surface. Spore balls (Fig. 4) usually irregular or globoid to ellipsoidal, composed of 2–15 spores, loose but rather permanent, 25–55(−70) × 20–40 μm, reddish brown, enclosed by subhyaline mucilaginous layer. Spores (Fig. 4) subglobose, ovoid, elongate or irregular, flattened on one or two sides, 15–20 × 12–16 μm, yellowish to pale reddish brown; wall uneven, 0.5–1.5 μm thick, smooth to rough, in SEM finely, densely, irregularly verruculose and covered by remnants of the mucilaginous layer which form irregularly warty (pseudo-)ornamentation. Spore balls and spores produced on the surface of host tissues in hyaline, sporogenous fungal layer within radially arranged, U-shaped pockets (Fig. 3C–F). Spore germination (Fig. 3G–H; on water, at room temperature, in 3–5 d) results in long, aseptate basidia on which apically elongated, cylindrical basidiospores are produced that germinate by filaments.

Bottom Line: Ustilago solida has previously been included in five different genera (Ustilago, Urocystis, Sorosporium, Cintractia, and Tolyposporium), however, molecular analyses revealed that this smut does not belong to any of these genera and represents a distinct ustilaginalean lineage.The description of Shivasia increases the number of endemic smut genera in Australasia to ten.Compared to all other continents the number of endemic smut genera is exceptionally high, which may point at fast evolving characters and/or may be caused by the regional history, including the long-term geographic isolation of Australasia.

View Article: PubMed Central - PubMed

Affiliation: Evolutionäre Ökologie der Pflanzen, Institut für Evolution und Ökologie, University of Tübingen, Auf der Morgenstelle 1, D-72076 Tübingen, Germany;

ABSTRACT
The generic position of the enigmatic smut fungus Ustilago solida is evaluated applying molecular phylogenetic analyses using ITS and LSU rDNA sequences as well as light and scanning electron microscopical investigations of several collections of this species. Ustilago solida has previously been included in five different genera (Ustilago, Urocystis, Sorosporium, Cintractia, and Tolyposporium), however, molecular analyses revealed that this smut does not belong to any of these genera and represents a distinct ustilaginalean lineage. The closest known phylogenetic relative of Ustilago solida is Heterotolyposporium lepidospermatis, the type species of the monotypic genus Heterotolyposporium. Both smuts differ considerably in both LSU sequences and in several morphological traits, such as the structure of sori and the characteristics of spore balls. Accordingly, the new genus Shivasia is described to accommodate Ustilago solida. This smut infects different Schoenus species (Cyperaceae) in Australia and New Zealand. The description of Shivasia increases the number of endemic smut genera in Australasia to ten. Compared to all other continents the number of endemic smut genera is exceptionally high, which may point at fast evolving characters and/or may be caused by the regional history, including the long-term geographic isolation of Australasia.

No MeSH data available.


Related in: MedlinePlus