Pythium porphyrae

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Pythium porphyrae
Systematics
Department : Egg mushrooms (Oomycota)
Class : Oomycetes
Order : Peronosporales
Family : Pythiaceae
Genre : Pythium
Type : Pythium porphyrae
Scientific name
Pythium porphyrae
M. Takah. & M. Sasaki , 1977

Pythium porphyrae (syn. Pythium chondricola De Cock , 1986) is a parasitic species from the Pythiaceae familywithin the group of egg fungi . It is the cause of a disease known in English as red rot disease or red wasting disease and in Japanese as akagusare (赤 ぐ さ れ ). The specific epithet porphyrae ( ancient Greek πορφυρα ) comes from the generic name of their most common hosts - porphyra - and the English common name from the purple color of the lesions onthe host's thallus . However, many of the infected hosts have now beengroupedinto the genus Pyropia .

description

Pythium porphyrae has a mycelial thallus that is eucarpic, i.e. H. only part of the thallus is converted to sporangia . The species is primarily a facultative parasite on algae, but it can also live saprotrophically .

The hyphae can be up to 4.5 µm wide and are not divided by septa . On algae, the hyphae begin to break through the host's cell walls. P. porphyrae has no haustoria or chlamydospores . The appressorias are club-shaped. The sporangia are unbranched, filamentous, and not distended; they usually form 6 ... 17 zoospores per vesicle. Encysted zoospores have a diameter of 8 to 12 micrometers. There are intercalary (inserted), spherical swellings of the hyphae with a diameter of 12 to 28 micrometers. The oogonia have an average diameter of 17 micrometers and are also intercalary and spherical, rarely terminal. In every oogon there are 1… 2 diclinic antheridia that are formed far away from the oogonia. The cells of the antheridia are club-shaped (clavate) or spherical. The antheridia are apical to the wall of the oogonia. Occasionally there are two antheridial cells on a hypha. The yellowish oospores have an average diameter of 15 µm, have thick (≈2 µm) walls and are plerotic, i. H. they fill out the danze oogon. The conidia are spherical with a diameter of 8.8 ... 30.8 micrometers, but are rarely produced.

P. porphyrae shares many physical characteristics with Pythium marinum and P. monospermum and appears to be closely related to P. adhaerens . However, the species has up to four diclinic antheridia and occasionally two antheridia cells per hypha; P. monospermum has 1… 4 either diclinic or monoclinic antheridia, and P. marinum has only a single diclinic antheridium. P. monospermum and P. marinum also have terminal oogonia on short hyphae branches, while those in P. porphyrae are intercalary.

In the laboratory, P. porphyrae grows on seawater cornmeal agar as a flat mycelium in the air with colorless colonies of up to 5 mm per day. It doesn't grow on a potato and carrot agar.

Distribution and ecology

Pythium porphyrae has been found in Japan , the Netherlands , New Zealand , and Korea , but this likely does not reflect the entire range.

The species attacks the following other species, all of which belong to the red algae :

  • Bangia atropurpurea
  • Callophyllis adhaerens
  • Chondrus crispus
  • Gelidium elegans
  • Gloiosiphonia capillaris
  • Gracilaria spp.
  • Grateloupia turuturu
  • Griffithsia subcylindica
  • Lomentaria hakodatensis
  • Mastocarpus papillatus
  • Polyopes affinis (syn. Carpopeltis affinis )
  • Polysiphonia morrowii
  • Pterocladiella capillacea
  • Pyropia cinnamomea
  • Pyropia plicata
  • Pyropia suborbiculata
  • Pyropia tenera
  • Pyropia virididentata
  • Pyropia yezoensis
  • Rhodymenia intricata
  • Stylonema alsidii
  • Wrangelia tanegana

Although some species of the genera Pyropia and Porphyra are sensitive to infections with P. porphyrae in their gametophytic phase , they are quite resistant in the sporophytic phase.

Taxonomy

A 2005 study on a case of pythiosis caused by the related Pythium insidiosum suggested that P. porphyrae is related to P. dissotocum , P. myriotylum , P. volutum and P. vanterpoolii .

A molecular analysis of the genus Pythium showed in 2004 that P. porphyrae belongs to " clade A" together with P. adhaerens , P. deliense , P. aphanidermatum and P. monospermum . This clade A has two clusters, and P. porphyrae shares one of them with a species that also grows on algae, P. adhaerens .

An examination of the Pythium species in clade A from 2017 showed the following phylogenetic tree .




P. deliense


   

P. aphanidermatum



   

P. monospermum


   

P. adhaerens


   

P. porphyrae / P. chondricola





   

P. insidiosum


It has also been shown that P. porphyrae and P. chondricola are identical. Pythium adhaerens could also be conspecific , which is ultimately based on a genetic comparison; however, a number of morphological differences suggest that they are separate, albeit very closely related, species.

Economical meaning

Pythium porphyrae can completely destroy a stock of nori within three weeks. The species prefers a low salinity and warm water (24… 28 ° C). Growth takes place only in a temperature range of 15 ... 35 ° C. Mild winters correlate with higher infection rates and lower yields, possibly because of the elevated temperatures that induce the maturation of the reproductive organs in the egg fungi. Losses can be reduced by removing infected fronds and exposing the thalli to air for 3… 4 hours a day. The oospores can be spread with contaminated organic matter, and the sporangia are spread via the water.

Individual evidence

  1. ↑ a b c d e f g h i j k l m n Minoru Takahashi, Takio Ichitani, Minoru Sasaki: ノ リ 赤 腐 病 を 起因 す る Pythium porphyrae (= Pythium porphyrae sp. Nov. Causing red rot of marine algae Porphyra spp. ) . In: Transactions of the Mycological Society of Japan . 18, No. 3, 1977, pp. 279-285.
  2. ↑ a b c d e f g h i j k l m Nora Diehl, Gwang Hoon Kim, Giuseppe C. Zuccarello: A pathogen of New Zealand Pyropia plicata (Bangiales, Rhodophyta), Pythium porphyrae (Oomycota) . In: Algae . 32, No. 1, March 2017, ISSN  1226-2617 , pp. 29-39. doi : 10.4490 / algae.2017.32.2.25 . Retrieved October 5, 2017.
  3. ↑ a b c d e f g h i j k C. André LéVesque, Arthur WAM De Cock: Molecular phylogeny and taxonomy of the genus Pythium . In: Mycological Research . 108, No. 12, December 2004, ISSN  0953-7562 , pp. 1363-1383. doi : 10.1017 / S0953756204001431 .
  4. ↑ Pythium porphyrae ( English ) 2016. Accessed October 4, 2017.
  5. ↑ Pythium porphyrae ( English ) National Center for Biotechnology Information. Retrieved October 2, 2017.
  6. ^ A b c d John H. Andrews: The Pathology of Marine Algae. Diseases caused by phycomycetes: Chytridiomycetes; Hyphochytridiomycetes; Oomycetes . In: Biological Reviews . 51, No. 2, May 1976, ISSN  1464-7931 , pp. 211-252. doi : 10.1111 / j.1469-185X.1976.tb01125.x .
  7. ↑ Chuck Griffith: Dictionary of Botanical Epithets ( English ) 2005. Retrieved October 3, 2017.
  8. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af M. A. Spencer: Pythium porphyrae. (Descriptions of Fungi and Bacteria) . In: IMI Descriptions of Fungi and Bacteria . 162, No. Sheet 1617, 2004. Retrieved October 10, 2017.
  9. ↑ a b c d e f g h i j k l m J. van der Plaats-Niterink: IX. Descriptions of the recognized species . In: Monograph of the genus Pythium ( English ) (= Studies in Mycology), Volume 21. Centraalbureau voor Schimmelcultures, Baarn, Netherlands December 22, 1981 (accessed October 6, 2017).
  10. ↑ Turkish Washcloth or Black Tar Spot ( English ) University of Puget Sound. 2017. Retrieved October 6, 2017.
  11. ↑ a b Satoshi Arasaki: ア サ ク サ ノ リ め 腐敗 病 に 關 す る 研究 (= Studies on the Wasting Disease of the Cultured Lavers ( Porphyra tenera )) . In: Nippon Suisan Gakkaishi (Bulletin of the Japanese Society of Scientific Fisheries) . 13, No. 3, 1947, ISSN  0021-5392 , pp. 74-90. doi : 10.2331 / suisan.13.74 .
  12. ↑ Christine Rivierre, Caroline Laprie, Olivier Guiard-Marigny, Patrick Bergeaud, Madeleine Berthelemy, Jacques Guillot: Pythiosis in Africa . In: Emerging Infectious Diseases . 11, No. 3, March 2005, ISSN  1080-6059 , pp. 479-481. doi : 10.3201 / eid1103.040697 . Retrieved October 5, 2017.
  13. ↑ S. Arasaki: The diseases of asakusanori and Their control . In: 病蟲害 雜誌 (Plant Protection) . 10, 1956, pp. 243-246.
  14. ↑ S. Arasaki: Studies on the artificial culture of Porphyra tenera Kjellm. 111. On the red wasting disease of Porphyra, especially on the physiology of the causal fungus Pythium sp. Nov. . In: Central Research Institute of Electric Power Industry (Ed.): Journal of the Agricultural Laboratory . 3, Abiko, Japan, 1962, pp. 87-93. "Japanese, with English summary"
  15. ^ S. Suto, Y. Saito, K. Akiyama, O. Umebayashi: Text Book of Diseases and their Symptoms in Porphyra ( Japanese ) (= Tokai Regional Fisheries Research Laboratory, Japan), Volume Contribution E, Number I 8 1972, p 37.
  16. ↑ Y. Sakurai, K. Akiyama, S. Sato: On the formation and the discharge of zoospores of Pythium porphyrae in experimental conditions . In: Bulletin of the Tohoku Regional Fisheries Research Laboratory . 33, No. I, 1974, pp. 19-27. "Japanese, with English summary"
  17. ^ S. Suto: Seaweed production and phycological research in Japan . In: Proceedings of the 1st International Seaweed Symposium, Edinburgh, 14-17 July 1952 . 1953, pp. 96-99.