Sclerotia cups

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Sclerotia cups
Sclerotia of Sclerotinia sclerotiorum

Sclerotia of Sclerotinia sclerotiorum

Systematics
Department : Ascomycota mushrooms
Subdivision : Real ascent mushrooms (Pezizomycotina)
Class : Leotiomycetes
Order : Helotials
Family : Sclerotia cup relatives (Sclerotiniaceae)
Genre : Sclerotia cups
Scientific name
Sclerotinia
Fuckel

The sclerotia cup ( Sclerotinia ) form a genus of fungi from the order of the Helotiales with some economically important plant pests such as Sclerotinia sclerotiorum , the causative agent of white stalk .

features

Macroscopic features

Sclerotinia species live parasitically on plants and form stalked cup-shaped fruiting bodies, the apothecia , which always arise from a sclerotium . The sclerotium contains no plant parts and is often found without the host plant. The apothecia are cinnamon to earth brown, the edge often being darker and 2 to 10 mm wide.

Microscopic features

The sclerotium consists of initially hyaline hyphae with gelatinized 2–3 μm thick cell walls ( textura intricata ). The outer excipulum consists of spherical, burn-walled cells, the textura prismatica . Spherical hyaline microconidia are formed both individually and in groups from bottle-shaped conidiophores . The asci are unitunicate, narrowed at the base, and have eight spores lying in a row. The ascus pore is blue with iodine. The paraphyses are filamentous and unbranched. The elliptical ascospores are hyaline, unicellularly smooth and have two oil droplets.

ecology

Sclerotinia species live parasitically on a variety of herbaceous plants. These include important plant pests such as Sclerotinia sclerotiorum , the pathogen causing white stalk or Sclerotinia trifoliorum , the pathogen causing clover . The former has a very large host range with over 350 species from 60 plant families and causes damage to oilseed rape in particular . Also Sclerotinia minor has a wide range of species, while Sclerotinia trifoliorum is restricted to legume. They occur worldwide. Apothecia are formed especially in cool, damp weather, arising from the damp sclerotium. This develops on rotten plant remains in the damp, wet soil. In temperate latitudes, the fruiting bodies are formed in spring, summer or autumn, depending on the species. In the tropics, their development is linked to the rainy season. Sclerotinia homoeocarpa is the causative agent of dollar spot disease on ostrich grasses .

species

In her monograph, the mycologist Linda M. Kohn counted only three species in Sclerotinia sensu strictu . Kirk et al. lists 14 species.

Systematics

Leopold Fuckel described the genus as early as 1870 and included all cuplets that either developed a stroma or a sclerotium. In 1945 Herbert Hice Whetzel restricted the genus to species that developed a true sclerotium without host tissue, did not have a conidial stage and produced hyaline spores. Thus, among other things, species such as the gray mold rot ( Botryotinia fuckeliana ) were placed in their own genus Botryotinia . In 1947 Buchwald placed species that developed microconidia and grow on rushes and sour grasses in the genus Myriosclerotinia . In 1979 Linda Kohn restricted the genus even more to only three species.

swell

Individual evidence

  1. ^ A b c d LM Kohn: A monographic revision of the genus "Sclerotinia". In: Mycotaxon. Volume 9, No. 2, 1979, pp. 365-444.
  2. ↑ David J. Lee: Sclerotinia homoeocarpa: Dollar spot of turfgrass. North Carolina State University. (on-line)
  3. ^ PM Kirk, PF Cannon, DW Minter, JA Stalpers: Dictionary of the Fungi. 10th edition. CABI, Wallingford, UK 2008, ISBN 978-0-85199-826-8 , p. 623.