Erwinia

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Erwinia
Systematics
Domain : Bacteria (bacteria)
Department : Proteobacteria
Class : Gammaproteobacteria
Order : Enterobacterales
Family : Enterobacteriaceae
Genre : Erwinia
Scientific name
Erwinia
Winslow et al. 1920

Erwinia is a genus of gram-negative rod bacteria from the Enterobacteria family(Enterobacteriaceae). They are facultatively aerobic ; H. in the presence of oxygen (oxic milieu) their energy metabolism is oxidative , if no oxygen is present ( anoxic milieu), they switch to fermentation in the energy metabolism. Almost all species are flagellated peritrich, so actively mobile. Many species of Erwinia (and species previously assigned to this genus) are pests of plants.

In the last few years there have been some changes in the classification of this group. Investigations showed differences in the DNA that were too great , so that many species belong to other genera ( Pantoea , Enterobacter , Pectobacterium and Brenneria ). However, especially in the agricultural sciences (due to their role as pests), the affected species are still listed and addressed under their old names.

metabolism

The members of the genus Erwinia are chemoorganotroph , they break down various organic substances to generate energy. They are facultatively aerobic; H. in the presence of oxygen they have an oxidative energy metabolism , they completely oxidize the organic substances to carbon dioxide (CO 2 ) and water. If there is no oxygen, they switch to 2,3-butanediol fermentation . The alcohol 2,3-butanediol is formed from glucose as the end product , and small amounts of acids are also formed. Other features of 2,3-butanediol fermentation are the intermediate product acetoin and a particularly high gas production (carbon dioxide CO 2 ). The intermediate product acetoin can be detected with the help of the Voges-Proskauer reaction . Further butanediol fermenters of enterobacteria are z. B. Enterobacter , Klebsiella and Serratia .

Other genera of enterobacteria also use an under anoxic conditions fermentation , but another form, called the mixed acid fermentation ( mixed acids fermentation ). In mixed acid fermentation, the end products are mainly acids such as acetic acid , lactic acid and succinic acid , but no butanediol . The mixed acid fermentation show u. a. the genera Escherichia , Salmonella and Proteus . The different end products and gas formations of the two metabolic pathways are an important feature for differentiating the genera.

Plant pathogenic species

Many Erwinia species break down plant residues, but are also involved in the development of plant diseases or are considered to be storage pests.

  • Erwinia carotovora (the system has been changed, the correct name is now Pectobacterium carotovorum ) triggers black- legged potatoes. The bacterium damages the plant by breaking down pectins with the help of the enzyme pectinase . Pectins are extracellular substances in the middle lamella of the plant cells that form a gelatinous adhesive layer between the cells. As a result of the breakdown, the affected plant tissue dissolves.
  • Erwinia amylovora is the causative agent of fire blight . Many species of the rose family (Rosaceae) are affected, especially pome fruit plants .
  • Erwinia billingia is another pest for various rose plants.
  • Erwinia cypripedii (correct name now Pectobacterium cypripedii ) damages various orchids, e.g. B. Cypripedium .

Some species have been found in humans or animals, but their role as pathogens has not been established.

Systematics

At the moment (January 2017) the following types of Erwinia are known.

Some changes

Various Erwinia species were placed in the genera Pantoea , Enterobacter , Pectobacterium and Brenneria (all belong to the Enterobacteria).

  • To the newly created (1999) genus Brenneria were u. a. the species Erwinia alni , Erwinia quercina , Erwinia rubrifaciens , Erwinia salicis and Erwinia paradisiaca (synonym: Dickeya paradisiaca ).
  • To Pantoea were the species Erwinia stewartii , Erwinia herbicola (synonym Enterobacter agglomerans ) milletiae Erwinia , Erwinia uredovora (synonym Erwinia ananatis transferred).
  • The genus Enterobacter now includes the species Erwinia cancerogena , Erwinia nimipressuralis and Erwinia dissolvens (synonym: Enterobacter cloacae subsp. Dissolvens ).
  • Erwinia carotovora , Erwinia chrysanthemi and Erwinia cypripedii were placed in the genus Pectobacterium .

swell

  1. ↑ Systematics and changes according to Euzéby: List of Prokaryotic Names with Standing in Nomenclature (LPSN) ( Memento of the original of November 8, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. As of January 2, 2012 @1@ 2Template: Webachiv / IABot / www.bacterio.cict.fr
  2. ↑ F. Rezzonico, Smits, THM; Born, Y .; Blom, J .; Frey, JE; Goesmann, A .; Cleenwerck, I .; de Vos, P .; Bonaterra, A .; Duffy, B .; Montesinos, E .: Erwinia gerundensis sp. nov., a cosmopolitan epiphyte originally isolated from pome fruit trees . In: Int J Sys Evol Microbiol . 66, 2016, pp. 1583–1592. doi : 10.1099 / ijsem.0.000920 .

literature

  • Martin Dworkin, Stanley Falkow, Eugene Rosenberg, Karl-Heinz Schleifer, Erko Stackebrandt (Eds.) The Prokaryotes, A Handbook of the Biology of Bacteria . 7 volumes, 3rd edition, Springer-Verlag, New York et al. O., 2006, ISBN 0-387-30740-0 . Vol. 6: Proteobacteria: Gamma Subclass ISBN 0-387-30746-X
  • Michael T. Madigan, John M. Martinko, Jack Parker: Brock - Mikrobiologie , Spektrum Akademischer Verlag , Heidelberg, Berlin 2001, ISBN 3-8274-0566-1