Microcyclus ulei

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Microcyclus ulei
Symptoms of Microcyclus ulei on leaves of the rubber tree: A Leaf deformation and sporulation of the GCL012 isolate 7 days after inoculation (B) Leaf with formation of a stroma 24 days after inoculation (C) A leaf with chlorotic areas 10 days after inoculation (D) End of germination Conidia, germ tube visible (450X magnification).

Symptoms of Microcyclus ulei on leaves of the rubber tree: A Leaf deformation and sporulation of the GCL012 isolate 7 days after inoculation (B) Leaf with formation of a stroma 24 days after inoculation (C) A leaf with chlorotic areas 10 days after inoculation (D) End of germination Conidia , germ tube visible (450X magnification).

Systematics
Subdivision : Real ascent mushrooms (Pezizomycotina)
Class : Dothideomycetes
Order : Botryosphaeriales
Family : Planistromellaceae
Genre : Microcyclus
Type : Microcyclus ulei
Scientific name
Microcyclus ulei
( Henn. ) Arx

Microcyclus ulei is a type of parasitic hose fungus and causative agent of the South American leaf fall disease , which is responsible in particular for very high crop failures in the cultivation of the rubber tree ( Hevea brasiliensis ) for the extraction of rubber in Brazil .

description

The hyphae of Microcyclus ulei are strong brown to black pigmented and cover leafy or stem surfaces in a web-like network.

The fungi form ascolocular fruiting bodies in the form of brown or black pseudothecia . These can be flat, shield-shaped, but also spherical or cushion-like and contain a loculus with one or a few asci . The club-shaped asci each contain 8 ascospores , which are mostly multicellular and brown or colorless.

distribution

The distribution of the fungus Microcyclus ulei is currently limited to the rainforests of the equatorial region of South America . Accordingly, it can be found mainly in Brazil and Peru .

Way of life

The host range of Microcyclus ulei is very narrow and limited exclusively to a few species of the plant genus Hevea . In addition to the rubber tree ( Hevea brasiliensis ), which is grown extensively in parts of Brazil, the fungus has been shown to infect the species H. guianensis , H. benthamiana , H. spruceana , H. camargoana and H. camporum . When young cassava plants are infected , the fungus causes strong defenses.

Economic impact

The infection with Microcyclus ulei in Brazil meant that plantation cultivation of the rubber tree is only possible to a limited extent. The former world market leader for natural rubber now only supplies 1.5% of world production, but needs around 4% of it. As a result of this restriction, Brazil is dependent on imports from Southeast Asia, especially from Malaysia , Indonesia and Thailand , where no comparable pathogens have yet been found.

War Weapons Control Act

Due to the great dependence of the economy on natural rubber and the resulting high economic importance, Microcyclus ulei belongs to the biological weapons according to Annex 1 of the War Weapons Control Act. This means that any handling of this pathogen is subject to various restrictions.

literature

  • HC Evans: Invasive Neotropical Pathogens of Tree Crops. South American Leaf Blight of Rubber: In: British Mycological Society Symposium, Roy Watling, J. Frankland, M. Ainsworth, C. Robinson (Eds.): Tropical Mycology: Volume 2: Micromycetes. CABI Publishing, 2000; Pp. 84-91, ISBN 0851995438 . ( Excerpts in Google Book Search )

Individual evidence

  1. ↑ a b Jens Hagen, Luadir Gasparotto, Vicente HF Moraes, Reinhard Lieberei: Reaction of cassava leaves to Microcyclus ulei, causal agent of South American leaf blight of rubber tree. Fitopatologia Brasileira 28 (5), Brasília 2003. ( full text )
  2. ↑ Rubber production in Brazil according to information from the Brazilian Ministry of Agriculture from October 19, 2017, accessed on May 12, 2018.
  3. ↑ F. Feldmann, JP Silva Jr., AVR Jayaratne: Use of arbuscular mycorrhiza in tree nurseries in the tropics using the example of the rubber tree Hevea spp. Notices from the Federal Biological Institute 363; Pages 83-92. ( PDF, 1.5MB ( Memento of the original from May 21, 2014 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Accessed on May 10th 2013) @1@ 2Template: Webachiv / IABot / www.feldmann-lifescience.de
  4. ↑ See Peter H. Raven et al. a. Biology of Plants Berlin 2000, p. 887 (3rd edition)
  5. ↑ https://www.gesetze-im-internet.de/krwaffkontrg/anlage.html