Orbiliaceae

Orbilia xanthostigma

The Knopfbecherchenverwandte ( Orbiliaceae ) are a family of ascomycetes, in a distinct order of Knopfbecherchenartigen ( Orbiliales ) and own class Orbiliomycetes stand. Some species are nematophag.

• 4.1 Nomenclature of nematophagous representatives
• 4.2 Evolution

• 5.1 Literature
• 5.2 Notes and references

Features

The fruiting bodies ( teleomorph, teleomorph ) are small (usually between 0.2 and 2 mm in diameter), waxy apothecia that are translucent or lightly pigmented to striking (usually with yellow to reds, rarely purple-violet or olivschwarz ). They usually grow on wood and bark, also on herbaceous substrates, old mushroom fruit bodies, animal residues, or on the ground. The excipulum (housing) consists of round to square or prismatic, translucent cells. At the edge of the apothecium is smooth or rarely occupied with hair of very different lengths, which may be bonded to teeth. The hymenium consists of paraphyses, which have often a clavate - capitate apex ( tip). The asci are often 8- sporig but also 16 -, 32 -, 64 - or 128- sporig, and their cell wall is nowhere amyloid. You are apically in dead state to saddle-shaped indented rounded or flattened (without turgor ), thin-walled or thick-walled mild to severe. Basal they vary from short and fat to long and thin stalked. The ascogenous hyphae are either simple or septate form at the septa hook. The interascale tissue is sometimes joined by a gel matrix and the outside often covered by an amorphous exudate.

The ascospores are always hyaline and almost always non-septate. They are depending on the type extremely varied and of very different sizes ( approximately 2-30 microns long ). On forms before coming: spherical, ellipsoidal, clavate, teardrop-shaped, fusiform, filiform, rarely triangular or heart-shaped. Not infrequently, the spores on the lower end have a more or less thin, tail -like extension that is sometimes swollen at the end. Elongated spores are often little to very strongly curved depending on the type.

Living ascospores possess an apical, highly refractive, soluble in KOH cytoplasmic inclusion of very different shape and unknown function. This " spore bodies" (spore body, SB) are also found to be more at both ends of spores in some species. You are a characteristic feature of Orbiliomycetes and known by any other class of Ascomycetes. The spore body as vacuoles by invagination of the cell membrane ( plasmalemma ) formed at the end of the spore maturation and remain a membrane - strand with the cell membrane in conjunction. They are filled with a refractive substance, the dark blue einfärbt at a vital staining with brilliant cresyl blue. On forms before coming: spherical, teardrop-shaped, filiform, pfropfförmig, lenticular. In some groups of the membrane strand is thinned out and elongated. Shape and size of ascospores and their spores within the body serve Knopfbecherchenverwandten as the main feature for the classification and species separation. In species with only one ( apical ) spores body some of the spores are almost always upside oriented ascus.

Another characteristic feature of some species are also to be observed only vital, KOH - soluble cytoplasmic body ( " soluble cytoplasmatic bodies", SCB) which, individually or in groups per cell occur in sterile tissue. These have a jagged shape, but are also happy to ring, horseshoe - or keyhole -shaped, and often pale orange.

Most species form a secondary fruit shape ( Anamorphic ), which is counted among the Hyphomycetes. This forms a hyaline or pale pink to orange mycelium and relatively large ( about 10-100 microns long), holoblastische, hyaline, septate conidia mostly of very different shape, curvature and branching ( ellipsoidal, clavate, filiform, C, Y, H-shaped, etc.).

Dissemination and lifestyle

The species occur worldwide. They live in the soil and on dead plant material and build from as decomposers of cellulose and lignin. Some representatives also form from traps and begin with nematodes. A type not described begins rotifers.

About 80 percent of the species grow on dry or at least temporarily desiccating plant material. These so-called xerotoleranten species fruiting bodies bear a complete drying out of many types for up to two to three years. Such species prefer extremely dry areas ( bushland, semi-deserts ), where they are protected from competition less adapted fungi. Representatives were found in 3500 m above sea level in Tibet.

Nematophagous representatives of the family are mostly found in temperate regions in permanently moist ground-level environment, but also occur in extremely dry areas such as Oman. Also on some Antarctic Islands ( Signy Iceland South Orkney Islands, and Galindez Island in the Argentine Islands, Wilhelm Archipelago, near the Antarctic Peninsula ) they were found in the soil.

System

The class is in addition to the Pezizomycetes the basalste group the Real Ascomycota. There are now around 360 known species, many of which have not yet been first described. A monograph on the Orbiliomycetes of Baral, Weber and Marson is in preparation.

Teleomorph

Eriksson 2006 called for the class two teleomorph genera:

• Hyalorbilia: The Ascusspitze is hemispherical and thin-walled. The asci are mostly short-stemmed and thick and always arise from hook. The excipulum usually consists of prismatic cells. In most species, the spores have one or more, usually spherical spores body at each end. The tips of the paraphyses are thickened to moderate. The hymenium is often gelatinous. The apothecia are usually hyaline to yellowish -chloro -colored, occasionally orange.
• Orbilia: The Ascusspitze is flattened hemispherical or saddle-shaped, and thin - to thick-walled. The asci are often long and thin stalked, usually basally branched dichotomously, and do not arise from hook. The excipulum usually consists of round to polygonal cells. The spores have only an apical spore body of very different shape. The tips of the paraphyses are thickened to strong. The hymenium is not gelatinous. The apothecia are hyaline, pink, orange, red or yellow, rarely black. The Artabgrenzungen are still often artificial, so are the teleomorph Orbilia already auricolor four known anamorphs.

• Pseudorbilia: 2007, a new genus Pseudorbilia the time being single type Pseudorbilia Bipolaris has been described: The Ascusspitze is flattened and thin-walled. The asci arise from hook. The excipulum consists of square cells. The spores are cylindrical to slightly dumbbell- shaped and have at each end a spore body. The tips of the paraphyses are thickened slightly. The hymenium is not gelatinous. The apothecia are hyaline.

Anamorphic

The anamorphs, there are about 12 genera. Eriksson et al. 2003 calls:

• Anguillospora
• Arthrobotrys
• Dactylella
• Dactylellina
• Dicranidion
• Drechsler Ella
• Dwayaangam
• Gamsylella: by Li et al. (2005 ) is the name synonymous with Dactylellina.
• Helicoon ( affiliation debatable )
• Lecophagus
• Tridentaria
• Trinacrium

According to recent studies, there are at least two other genera:

• Brachyphoris
• Vermispora

Nematophagous representatives

Some anamorphic genera are able to catch nematodes (roundworms ). They represent the majority of the nematophagous fungi. Your traps are one of three basic types: adhesive knobs, sticky nets and catch loops. The case type has proven to be taxonomically useful feature, in contrast to the conidia and conidiophores long forms used.

Nomenclature of nematophagous representatives

According to the investigations by Li et al. only three species of nematophagous fungi are distinguished in the family, the genus Gamsylella is no longer considered valid. Due to molecular genetic studies group the previously known forms in three genera that have the following types of cases:

• Drechsler Ella: The trap is a contracting loop, which consists of three when touched by a nematode abruptly swelling cells and a short, strong stem.
• Arthrobotrys: The case is a ungestielter adhesive button, which further develops into an adhesive network, or occur only adhesive nets. The following two types are of Li et al. newly circumscribed in its scope: Arthrobotrys arcuata
• Arthrobotrys gephyropaga

• Dactylellina candidum
• Dactylellina lobata
• Dactylellina parvicolle
• Dactylellina phymatopaga
• Dactylellina robusta

Evolution

The nematophagous representatives emerged from nichtnematophagen ancestors of the genus Orbilia. They form a monophyletic group within the Knopfbecherchenverwandten. However, within their kinship group, next to representatives with adhesive knobs, some nichtnematophage species of the genus Dactylella. A possible explanation is that these species have lost the adhesive knobs again. The loss of these structures is also known in nematophagous se types in culture. The species with adhesive knobs are also closer to the nichtnematophagen Dactylella - types are used than with those kinds with other traps.

Adhesive knobs are considered more original feature, loops and adhesive networks as derived forms. These are much more effective in trapping nematodes as the nematodes in adhesive knobs are held only at one point. When bonding networks they remain at several points hanging in the loop they are actively held and strangled by swelling of the cells. This presumed evolutionary lines are firstly by the molecular genetic studies supported the relationship, the other by the ontogenetic development in species with several case types. In several species was observed, as were formed from adhesive knobs nets or loops.

The types of cases developed in two evolutionary lines: One line led to the capture loops, the other to the sticky traps. From early in the latter branched off the line to the adhesive networks, while developed the main line to the adhesive knobs. Led via an extension of the stem, to the forms of not contracting loops.

Swell