Xylella fastidiosa

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Xylella fastidiosa
Systematics
Department : Proteobacteria
Class : Gammaproteobacteria
Order : Lysobacterales
Family : Lysobacteraceae
Genre : Xylella
Type : Xylella fastidiosa
Scientific name
Xylella fastidiosa
Wells et al., 1987
Oleander leaf brandy; Effects of the infestation of Nerium oleander by the bacterium Xylella fastidiosa
Homalodisca vitripennis , a dwarf leafhopper , can transfer the bacterium into the xylem of the plantwhen it sucks in the sap .

Xylella fastidiosa , dt. Also fire bacterium is a bacterium from the family Lysobacteraceae (formerly known as Xanthomonadaceae hereinafter). It is the causative agent of diseases in more than 100 plant species , including numerous useful plants .

Among other things, it triggers the plant diseases phony peach disease (dt. Fake / false peach Disease ), oleander leaf scorch (dt. Oleander -Blatt-fire ), citrus cancer ( citrus variegated chlorosis disease , a variety of citrus chlorosis Disease ) and of vines , the "Pierce's disease" ( Pierce's disease ) from. It also attacks almond , olive and plum trees .

All xylem- sucking insects in Europe are potential carriers of the bacterium. This means that combating the bacterium is particularly difficult because the bacterium is transmitted by different insects; In addition, infected plants show no symptoms for months , so that the spread remains undetected for a long time.

The speed of spread of X. fastidiosa in countries where the bacterium has already been reported is very high, especially in plantations. A plant protection product that could be used on already infected plants is not yet known; the European Food Safety Authority therefore recommends controlling the transmitting insect species and checking plants thoroughly for infestation before shipping them to other regions.

Due to the diversity of the subspecies in Europe, it is now assumed that the bacteria were not just once, but several times from America - where they are endemic (native) - to Europe.

New technology for early detection of infestation

With the help of a hyperspectral camera and recordings made by drones at a height of approx. 500 meters above plantings, the smallest deviations in the plants can be visibly displayed. The magazine Nature reports for the first time about this new technology, the hope in the fight against this dangerous and incurable plant disease that has spread uncontrollably until now. With a resolution of 40–60 cm, individual plant photos can be analyzed in 250 color spectra , which are much more accurate and comprehensive than can be seen with the naked eye. This means that even the smallest changes in the infested plants and trees can be recognized, which lead to the typical dehydration. This technique gives hope to detect the spread early and to combat it.

Genome

In 2000, the entire genome of the species was deciphered in São Paulo ( Brazil ) : 200 scientists worked on DNA sequencing for two years . It found that the genome of the bacterium comprises 2,679,305 base pairs . Approx. 50% of the coding regions could be assigned to presumed functions; there is ample evidence of the cause of the disease in infected plants.

Pierce disease

This vine disease was first examined in 1892 by Newton B. Pierce , one of the first phytopathologists , on the noble grapevine ( Vitis vinifera ) in California , and his description appeared in 1900. The name of this plant disease in wine is therefore Pierce’s disease in English . The pathogen causes the water and nutrient balance of the plant to be blocked, which leads to its death after two to three years. In addition, the leaves of the infected vines turn yellow and the fruits produced are small and hard.

In 1996 it was found that the vector (carrier) of this disease is a dwarf leafhopper of the genus Homalodisca : Homalodisca vitripennis . This insect feeds on plant sap and thus transfers the bacterium to the xylem of the plants, where it develops and multiplies.

The disease is caused by the subspecies Xylella fastidiosa fastidiosa and has also been found in Costa Rica , the southeastern United States , Mexico and Venezuela .

Infestation of fruit trees in Europe

The bacterium leads to the death of the olive tree , it also causes the plants to dry out and die off (OQDS, olive quick decline syndrome ).

The way in which the bacterium from North - and Latin America to Southern Europe introduced was, is unclear. In 2013, the bacterium appeared for the first time on 8,000 hectares (ha) in Salento in southern Italy, at the beginning of 2015 around one million infested olive trees will have to be felled on an estimated 230,000 hectares in the province of Lecce ; further rapid spread is feared. In addition, in order to effectively prevent further spread, the entire area must be mowed, the soil must be plowed and pesticides must be used. Corresponding bacteria were also found in a greenhouse near Tours (France) in 2012 and on the Cote d'Azur in 2015 and in a container plant in Propriano (Corsica). On August 18, 2016 in Corsica, 279 foci of infection were identified, mainly in the south and west of the island.

In 2015, Italian prosecutors halted the EU order and launched investigations into researchers and local officials who are accused of providing "false facts" and misleading the EU. There is “no evidence” of a connection between the bacterium and the signs of drying out of thousands of trees in southern Italy. This order was only withdrawn in July 2016 after the threat of a lawsuit before the European Court of Justice . In May 2017, environmentalists opposed to the deforestation filed a complaint with the public prosecutor with the aim of investigating other possible causes such as fungal infections, although this had already been ruled out by the EU

Xylella fastidiosa also affects almond , peach ( phony peach disease ) and plum trees as well as citrus fruits , as well as oleander ( oleander leaf scorch ). Other host plants in which the bacterium has been detected are: sweet cherry (Prunus avium), willow-leaf acacia (Acacia saligna), periwinkle (Vinca rosea), rosemary (Rosmarinus officinalis), Australian rosemary (Westringia fruticosa), finial (Polygala myrtifolia) and evergreen buckthorn (Rhamnus alaternus).

As a countermeasure, the EU has imposed an import ban on certain coffee trees from Honduras and Costa Rica .

In 2016 Xylella f. first detected in Germany.

At the end of 2016, the bacterium was also identified in the Balearic Islands . As a result of the investigations, it was suspected that the bacterium had been able to spread on Mallorca since 2012 and that up to 12,000 almond trees died in the middle of the island as a result. Investigations of the bacterium have shown that this is the aggressive form Xylella fastidiosa pauca , which, in addition to the trees already mentioned, also includes olive trees, cherry trees, laurel bushes , willow leaf acacias , lavender , rosemary , Australian rosemary ( Westringia fruticosa ) and Finials can attack.

On February 28, 2017, the Mallorca Zeitung reported that the biologist Eduardo Moralejo informed the Ministry of Agriculture in 2010 about the spread of the bacterium in Mallorca. Moralejo accused the ministry of covering up the real cause of the almond tree death for economic policy reasons. Since spring 2017, there has been an export ban from the Balearic Islands to mainland Spain for all plants that are infected by the pathogen. Moralejo names a finca near Son Carrió near San Llorenç as the origin of the spread . Biomaterial originating from California was applied here in 1996 for experimental purposes. In his opinion, Xylella fastidiosa has been spreading on the island since then. Thus Mallorca is also the first European region to be infected by Xylella. Since 2008, around 100,000 almond trees have died on Mallorca. Around a million almond trees are already infested and the bacterium is also spreading to vines, olive trees, fig trees and various ornamental plants. Moralejo's hypotheses are now considered confirmed and research into ways of dissemination and countermeasures continues.

Measures and protection against the spread

In 2015, the EU authorities published a guideline to prevent plant protection and the further spread of the disease. Among other things, it was ordered that a 100 meter wide zone and a 10 kilometer wide buffer zone must be built around the infestation. In a later EU decision, amended in 2017, this buffer zone was reduced to five kilometers. Furthermore, it was ordered that an EU plant passport is compulsory for a number of plants intended for trade, which are considered to be host plants for the pathogen. Infested plants need to be removed and burned.  

See also

Web links

Commons : Xylella fastidiosa  - album with pictures, videos and audio files
  • Plant health website of the Julius Kühn Institute / Federal Research Institute for Cultivated Plants on Xylella fastidiosa including a list of susceptible host plants in the EU
  • Spektrum.de: An olive grove infested with Xylella fastidiosa.
  • Brigitte Kramer: Bacterium threatens olive and almond trees - EU advises radical deforestation measures ( memento of July 10, 2017 in the Internet Archive ), Bayerischer Rundfunk, April 19, 2017
  • Nature article on early detection by drones [1] , 2018
  • Barbara Bachmann (text), Patricia Kühfuss (photos) The roots of a region ; Text in ' brand eins ' on the infestation of olive trees. [2]
  • Official Journal including the list of plants known to be susceptible to European and non-European isolates of the specified organism ("specified plants") and the list of plants known to be susceptible to European isolates of the specified organism ("host plants") [3]
  • Julius Kühn Institute Federal Research Institute for Cultivated Plants [4]
  • NZZ article from June 17, 2019 by Angela Schader and Gilles Steinmann: "Salento dies with the trees" [5]
  • "Mallorca on the trail of fire bacteria", by Barbara Pohle. In: Mallorca Zeitung from September 16, 2019 [6]

literature

  • SM. Mang, S. Frisullo, HS. Elshafie, I. Camele: Diversity Evaluation of Xylella fastidiosa from Infected Olive Trees in Apulia (Southern Italy) . April 2016. In: J Microbiol Methods. PMID 27147930
  • Q. Yuan, R. Jordan, RH. Brlansky, O. Istomina, J. Hartung: Development of single chain variable fragment (scFv) antibodies against Xylella fastidiosa subsp. pauca by phage display . October 2015. In: J Microbiol Methods. PMID 26232710
  • IE. Ben Moussa, V. Mazzoni, F. Valentini, T. Yaseen, D. Lorusso, S. Speranza, M. Digiaro, L. Varvaro, R. Krugner, AM. D'Onghia: Seasonal Fluctuations of Sap-Feeding Insect Species Infected by Xylella fastidiosa in Apulian Olive Groves of Southern Italy. August 2016. In: J Econ Entomol. PMID 27401111
  • A. Fierro, A. Liccardo, F. Porcelli: A lattice model to manage the vector and the infection of the Xylella fastidiosa on olive trees . In: Nature - Scientific Reports . 9, No. 1, 2019, p. 8723. doi : 10.1038 / s41598-019-44997-4 .

Individual evidence

  1. ^ Jean Euzéby, Aidan C. Parte: Family Xanthomonadaceae. In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved December 16, 2019 .
  2. ^ Jean Euzéby, Aidan C. Parte: Classification of domains and phyla - Hierarchical classification of prokaryotes (bacteria). In: List of Prokaryotic names with Standing in Nomenclature, Systematics of Bacteria (LPSN) . Retrieved December 16, 2019 .
  3. ↑ Badische-zeitung.de , March 26, 2015, Julian Müller-Meiningen: Fire bacteria kills olive trees in southern Italy
  4. ↑ Almeida, RPP (2016). "Can Apulia's olive trees be saved?" Science 353 (6297): 346-348. doi: 10.1126 / science.aaf9710
  5. ↑ wiley.com: Wiss. Opinion on risks to plant health with regard to Infestation with X. fastidiosa and evaluation for risk reduction
  6. ↑ a b c d Alison Abbott: Bacteria Infection - Massensterben im Olivenhain , in Spektrum.de from July 5, 2017 (German), original article : Alison Abbott: Italy rebuked for failure to prevent olive-tree tragedy - European Commission reveals widespread delays by the country's authorities to halt spread of deadly plant disease , in nature.com from June 7, 2017 (English)
  7. ↑ "Flying cameras can spot lethal disease sweeping through world's olive groves". In: The Guardian, June 25, 2018. Retrieved July 1, 2018.
  8. ↑ "Now a drone is tackling the fire bacteria on Mallorca". In: Mallorca Zeitung of June 26, 2018, accessed on July 1.
  9. ↑ nature: The genome sequence of the plant pathogen X. fastidiosa, Nature 406, 151-157 (2000)
  10. ^ Newton B. Pierce: Peach leaf curl: its nature and treatment. United States Division of Vegetable Physiology and Pathology, Bulletin no.20, Washington 1900
  11. ↑ Spiegel.de , November 28, 2013, Hans-Jürgen Schlamp: Tree dieback: Fire bacterium destroys olive groves in southern Italy
  12. ↑ New cases of Xylella Fastidiosa in the Alpes-Maritimes ( Memento from January 19, 2016 in the Internet Archive )
  13. ↑ Spiegel 32/2015, p. 101, Katrin Elger: Killer Xylella
  14. ↑ Xylella: carte et liste des communes en zones délimitées en Corse au August 18, 2016 ( French ) Direction régionale de l'alimentation, de l'agriculture et de la forêt de Corse. Retrieved August 23, 2016.
  15. ↑ Felling of olive trees in Italy stopped , orf.at December 20, 2015, accessed December 21, 2015
  16. ^ Xylella, die Schreckliche , Süddeutsche April 27, 2015, accessed July 8, 2017
  17. ↑ Italy - Battle of the Olive Trees , arte June 15, 2016
  18. ↑ European Food Safety Authority (efsa): Xylella "causes olive disease in Italy" from March 29, 2017.
  19. ^ "Phony peach: the disease that threatens to devastate Britain's trees and plants". In: The Guardian, online February 14, 2016, accessed February 11, 2017.
  20. ↑ "PLANT DISEASE: OLEANDER LEAF SCORCH". From website http://www.azplantlady.com/ on March 20, 2017. Retrieved February 11, 2017.
  21. ↑ "The fire bacterium - Xylella fastidiosa". On the website http://www.provinz.bz.it . Retrieved July 11, 2019.
  22. ↑ Spiegel 32/2015, p. 101, Katrin Elger: Killer Xylella
  23. ↑ "Fire bacteria: parts of Zeulenroda-Triebes declared a restricted zone" , otz.de August 3, 2016
  24. ↑ "The fire bacterium is here" , in: Mallorca Zeitung - online, from December 15, 2016, accessed on February 9, 2017
  25. ↑ "Fire bacteria in Mallorca: a bad suspicion". In: Mallorca Zeitung - online from February 2, 2017, accessed on February 9, 2017.
  26. ↑ "La 'xylella' hallada en Ibiza pertenece a la variant más agresiva." In: Diario de Ibiza of February 11, 2017, accessed on February 11.
  27. ↑ "Scientists: Fire bacteria on Mallorca since 2005." In: Mallorca Zeitung of February 28, 2017, accessed on February 29.
  28. ↑ "Cifran en un millón los almendros infectados por la Xylella en Mallorca - Diario de Mallorca" In: Diario de Mallorca, October 8, 2017 (Spanish). Retrieved October 11, 2017.
  29. ↑ "Noticias de Xylella Fastidiosa - Diario de Mallorca" In: Diario de Mallorca, link table to all articles published on the subject (Spanish). Retrieved October 11, 2017.