A ProMED-mail post <http://www.promedmail.org>
ProMED-mail is a program of the International Society for Infectious Diseases <http://www.isid.org>
Date: July 2019
Source: New Disease Reports [edited]
<https://www.ndrs.org.uk/article.php?id=040004>
[Ref: Mambetova S, Rosenzweig N, Hammerschmidt R, et al. First report of pod wart disease of peanut caused by _Streptomyces_ spp. in the Western Hemisphere. New Disease Reports 40, 4, doi: 10.5197/j.2044-0588.2019.040.004]
Pods with wart-like symptoms were collected from peanut (_Arachis hypogaea_) plants at [a] University of Georgia farm. Putative pathogenic _Streptomyces_ spp. were isolated from peanut pericarp.
Individual bacterial [cultures] from a single wart-like lesion, similar [in appearance] to typical pathogenic strains of _Streptomyces_ spp., revealed typical structures [under] scanning electron and light microscopy.
Targeting the 16S rRNA, recombinase A, RNA polymerase b-subunit and thaxtomin synthase (txtAB), PCR product sequences revealed 99% to 100% identity with _Streptomyces_ spp. and had the pathogenicity gene encoding txtAB.
Three plants were inoculated with bacterial suspension, peanuts were harvested 133 days after planting and assessed for the presence of wart symptoms. _Streptomyces_ spp. were re-isolated from symptomatic pericarps as described above. The recovered bacteria were identified using 16S rRNA, recA, and rpoB sequences, thus fulfilling Koch's postulates.
Peanut wart has been reported in Israel and South Africa. However, to our knowledge, this is the 1st report of _Streptomyces_ spp. causing pod wart disease of peanut in the United States and the Western Hemisphere.
--
Communicated by:
IBIS (International Biosecurity Intelligence System) <https://ibisbiosecurity.org/>
[Pod wart of peanut was first described from Israel and subsequently attributed to bacteria of genus _Streptomyces_ as causal agents.
Different _Streptomyces_ species or combinations are suspected to be causing the disease in different areas. In South Africa, _S. scabiei_ was found to be associated with the disease on peanut crops grown in rotation with potato, with symptoms ranging from net blotch with scattered lesions to dark brown, necrotic, warty lesions (see link below).
_S. scabiei_ is known to cause common scab of potato with symptoms including cracks and lesions on tubers that coalesce into large rough or corky areas, but above ground plant parts appear normal. Scab reduces crop quality, although scabby potatoes are generally fit to eat and store. Infection occurs during early tuber formation, and if soils are dry at that stage, disease levels can be high. _S. scabiei_ can also affect other root crops, such as carrot, parsnip, radish, beet, and turnip. Each of the crops can serve as reservoir host in case of successive rotations.
The bacteria are soil-borne and can survive on infected underground plant parts (tubers, roots) and plant debris. Disease management requires an integrated approach and may include cultural techniques such as 3-5 year rotations with non-host crops, increase of organic matter in fields to increase soil moisture and adjusting soil pH. Use of certified clean planting material is essential. Crop cultivars may vary in disease susceptibility. Not all species in the genus are pathogens and research is being carried out into biological control of pathogenic species by antibiotic-producing strains of _Streptomyces_.
Maps
USA:
<http://www.mapsofworld.com/usa/usa-state-and-capital-map.html> and <http://healthmap.org/promed/p/106>
Individual states via:
<http://www.mapsofworld.com/usa/states/>
Pictures
Symptoms of _Streptomyces_ spp on peanut pods:
<https://ai2-s2-public.s3.amazonaws.com/figures/2017-08-08/8f4b2031953f8dd07dbabb8850e0986707a256b7/6-Figure1-1.png>
and via
<https://tinyurl.com/y38mfg9g>
Common scab on potato:
<https://ag.umass.edu/sites/ag.umass.edu/files/fact-sheets/images/potato_scab.jpg>,
<http://www.omafra.gov.on.ca/IPM/images/potatoes/diseases/common-scab/potato_common-scab_06_zoom.jpg>,
<http://vegetablemdonline.ppath.cornell.edu/Images/Potatoes/PotatoScab/PotatoScabColl.jpg>,
and
<http://www.omafra.gov.on.ca/IPM/images/potatoes/diseases/common-scab/potato_common-scab_01_zoom.jpg>
(close-up of lesion)
Scab on beet:
<http://mtvernon.wsu.edu/path_team/DiseaseGallery/dg13L.jpg>
Links
Information on peanut net blotch and pod wart by _Streptomyces_ spp:
<https://link.springer.com/article/10.1007%2FBF02981412>,
<https://www.sciencedirect.com/science/article/pii/S0261219496001093>,
<https://www.apsnet.org/publications/plantdisease/1997/August/Pages/81_8_958.2.aspx>
(_S. scabiei_), and via
<http://www.ecpgr.cgiar.org/fileadmin/templates/ecpgr.org/upload/Presentations/GL_2013/15_Israel_Legumes_resources_in_Israel_-_Ran_Hovav.pdf>
Information on scab on potato & beets and _S. scabiei_:
<https://potatoes.ahdb.org.uk/media-gallery/detail/13214/2638>,
<http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/plant-diseases/vegetable/potato-diseases/common-scab-of-potatoes>,
and
<http://www.plantwise.org/KnowledgeBank/Datasheet.aspx?dsid=51840>
_Streptomyces_ taxonomy and species list <https://www.uniprot.org/taxonomy/1883>
- Mod.DHA]
[See Also:
2017
----
Common scab, potato - UK http://promedmail.org/post/20170904.5294699
2007
----
Streptomyces common scab, potato - USA (ID): new strain
http://promedmail.org/post/20070427.1368
2005
----
Verticillium wilt, eggplant - Italy
http://promedmail.org/post/20050816.2401]
Topics
Species
