Biology:Plasmopara obducens

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Short description: Species of single-celled organism

Plasmopara obducens
Scientific classification edit
Domain: Eukaryota
Clade: Diaphoretickes
Clade: SAR
Clade: Stramenopiles
Phylum: Oomycota
Order: Peronosporales
Family: Peronosporaceae
Genus: Plasmopara
Species:
P. obducens
Binomial name
Plasmopara obducens
(J. Schröt.) J. Schröt., (1886)
Synonyms
  • Peronospora obducens J. Schröt., (1877)
  • Rhysotheca obducens (J. Schröt.) G.W. Wilson, (1907)
  • Peronospora impatientis Ellis & Everh., (1892)
  • Plasmopara impatientis (Ellis & Everh.) Berl., (1898)

Plasmopara obducens is a species of oomycete that causes Impatiens downy mildew. It was first described on Impatiens noli-tangere in Germany in 1877. Plasmopara obducens is known from native[where?] species of Impatiens since the 1800s, but outbreaks on cultivated varieties of Impatiens walleriana started in 2003 in the United Kingdom and in 2004 in the United States .[1] The outbreak spread worldwide by 2016.[2]

Morphology

Sporangiophores are an average of 373 (260-484) micrometers with the first branch appearing at 197 (120-271) micrometers. Sporangia are 16 (13-18) micrometers by 13 (11-16) micrometers. [3] Resting spores are globose with a diameter of 28 micrometers [1]

Disease symptoms

Initially, leaves are stippled or yellowed. Infected leaves curl downward. A white down is often present on the underside of the leaves; buds and stems may also develop a down. Eventually, the leaves fall off the plant leaving just stems. [4] In about a week, the plants are dead.[2]

Taxonomy

J. Schröter originally placed the species in the genus Peronospora but later moved it to the genus Plasmopara. [5] Some authors believe the outbreaks on I. walleriana and I. balsamina are not caused by P. obducens but two new species P. destructor and P. velutina. [3]

References

  1. 1.0 1.1 Shishkoff, Nina (2019). "The oospore state of Plasmopara obducens, impatiens downy mildew". Mycologia 111 (4): 632–646. doi:10.1080/00275514.2019.1601986. PMID 31136264. 
  2. 2.0 2.1 Derevnina, Lida; Petre, Benjamin; Kellner, Ronny; Dagdas, Yasin F.; Sarowar, Mohammad Nasif; Giannakopoulo, Artemis; De la Conception, Juan Carlos; Chaparro-Garcia, Angela et al. (2016). "Emerging oomycete threats to plants and animals". Philosophical Transactions of the Royal Society B 317. 
  3. 3.0 3.1 Görg, Marlena; Ploch, Sebastian; Kruse, Julia; Kummer, Volker; Runge, Fabian; Choi, Young-Joon; Thines, Marco (2017). "Revision of Plasmopara (Oomycota, Peronosporales) parasitic to Impatiens". Mycological Progress 16 (8): 791–799. doi:10.1007/s11557-017-1316-y. 
  4. Rosetta, Robin (2014). "Downy mildew on impatiens". http://oregonstate.edu/dept/nurspest/impatiens_downy_mildew.html. 
  5. Kryotogamen-Flora von Schlesien. 3-1. 1886. pp. 129–256. 

External links

Wikidata ☰ Q7201992 entry