Synchytrium endobioticum

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Synchytrium endobioticum
Synchytridium endobioticum.jpg

Synchytrium endobioticum

Systematics
Department : Potty mushrooms (Chytridiomycota)
Class : Chytridiomycetes
Order : Chytridiales
Family : Synchytriaceae
Genre : Synchytrium
Type : Synchytrium endobioticum
Scientific name
Synchytrium endobioticum
( Schilb. ) Percival

Synchytrium endobioticum is, the potato wart -causing potty fungus . It can also attack other nightshades, but the potato is the only cultivated plant that can be infected.

There are at least 18 pathotypes of the fungus, most of which are not very common in Central Europe. Race 1 is the most widespread.

morphology

Like some other chytridiales, the fungus does not develop mycelium . It develops a thick-walled structure called "winter sporangium ". It is 25–75 µm thick and contains 200–300 spores. The sporangia are grouped in thin-walled sori . The mobile zoospore has a diameter of approx. 0.5 µm and has a posterior flagellum .

Life cycle

The overwintering sporangia germinate at the higher temperatures in spring with high humidity. In doing so, they release zoospores that infect suitable host cells. The summer sporangia develop in the infected cells, which quickly release new populations and zoospores. The infection cycle lasts as long as the living conditions are suitable for the fungus. Affected plant cells swell, divide and surround the dividing zoospores, which results in visible wart formation.

Under certain stress conditions, pairs of zoospores fuse to form a zygote . The cells containing the zygote divide and eventually form the wall of a new winter sporangium. In autumn, the warts decay, releasing new, thick-walled spores into the ground. These diploid, overwintering spores go through a resting phase. Before they germinate, a meiotic division and some mitotic divisions (probably) take place, which ultimately leads to sorus .

ecology

Three different fungi are known that can parasitically attack the dormant sporangium. It is a unicellular, soil-borne, necessarily parasitic fungus. Its preferred environmental conditions are moderate temperatures (not above 20 ° C) with sufficient humidity. An infected potato can be recognized by typical growths.

The spores can survive in the ground to a depth of 50 cm. Winter spores can remain viable for 20–40 years, although they are very heat-tolerant but also very cold-tolerant. Because of the resilience of the spores, feeding infested potatoes can spread the disease through animal excrement. A cultivation ban for an unlimited period therefore applies to an infested cultivation area. It is also possible to spread it through contaminated agricultural machinery.

The fungus originated in the Andes region of South America, but has now spread almost everywhere in the world where potatoes are grown, but not in most of the tropical regions of Africa, the Middle East, Canada, Japan and Australia.

The fungus poses a threat to potato cultivation because it cannot be controlled. However, there are resistant varieties of potatoes.

swell