Puccinia monoica
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Puccinia monoica on rockcress |
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Puccinia monoica is a stand fungal art from the order of the rust fungi (Pucciniales). The fungus is an endoparasite of cruciferous plants and various sweet grasses . Symptoms of the infestation by the species are rust spots and pustules on the leaf surfaces of the host plants. It is common in North America .
features
Macroscopic features
Puccinia monoica forms in the Haplontenphase at the growing tip of its host, usually Arabis , with converted yellowed leaves of a "pseudo flower". On the dikaryote host , the fungus can only be recognized with the naked eye by means of the spore beds protruding on the surface of the host. They grow in nests that appear as yellowish to brown spots and pustules on the leaf surfaces.
Microscopic features
The mycelium of Puccinia monoica grows as with all Puccinia TYPES intercellular and forms Saugfäden that grow into the storage tissue of the host. The systemic aecia of the fungus have 17–30 × 15–24 µm large, hyaline aeciospores with a wrinkled surface. The cinnamon-brown uredia of the species mostly grow on the top of the leaves of the host plant. Their golden to cinnamon-brown uredospores are usually broadly ellipsoid, 26–30 × 22–26 µm in size and finely spiky. The parts of the species that usually grow on the upper side of the leaves are black-brown, powdery and exposed early. The golden to light hazelnut-brown teliospores of the fungus are two-celled, usually long ellipsoid and 40–51 × 19–23 µm in size. Their stalk is yellowish and up to 120 µm long.
distribution
The known distribution area of Puccinia monoica extends from British Columbia and Wisconsin to New Mexico .
ecology
The host plants of Puccinia monoica for the Haplonts are cruciferous plants , especially goose cress ( Arabis spp.) And Boechera as well as various grasses for the dikaryotes . The fungus feeds on the nutrients present in the storage tissue of the plants, its spore beds later break through the leaf surface and release spores. The species has a development cycle with Telien, Uredien, Spermogonia and Aecien and changes host. Puccinia monoica is similar to Uromyces pisi in Haplontenphase at the growing tip of its host, usually Arabis , a "pseudo Flower" from. These imitate yellow-blooming wildflowers like buttercups not only in visible light, but also in the near ultraviolet range , which is visible to bees and therefore attractive. In addition, they also release various scents ( phenols , aldehydes and esters ) in order to be as similar as possible to real flowers. Also, caused by the fungus, the host creates a sweet sticky substance that the bees feed on.
Systematics
Puccinia monoica consists of a whole complex of species. At least four types are distinguished: Puccinia monoica Sensu stricto , Puccinia consimilis , Puccinia thlaspeos and Puccinia holboellii , which only differ in their cycle (host change or not) and the presence of different spore stages. According to molecular biological studies, there are probably more cryptic species.
literature
- George Baker Cummins: The Rust Fungi of Cereals, Grasses and Bamboos . Springer, Berlin 1971, ISBN 3-540-05336-0 .
Individual evidence
- ↑ a b BA Roy: Floral mimicry by a plant pathogen . In: Nature . tape 362 , 1993, pp. 56–58 ( nature.com [PDF]).
- ^ RA Raguso, BA Roy: 'Floral' scent production by Puccinia rust fungi that mimic flowers. In: Mol Ecol. Volume 7, 1998, pp. 1127-1136. (on-line)
- ^ BA Roy, RA Raguso: Olfactory versus visual cues in a floral mimicry system. In: Oecologia. Volume 109, 1997, pp. 414-426. (on-line)
- ↑ C. Zimmer: Parasite Rex: Inside the Bizarre World of Nature's Most Dangerous Creatures. Simon & Schuster, New York 2000.
- ↑ Barbara A. Roy, Detlev R. Vogler, Thomas D. Bruns, Timothy M. Szaro: Cryptic Species in the Puccinia monoica Complex. In: Mycologia. Volume 90, 1998, pp. 846-853. (on-line)
