[2] Unlike most of the 500 or so Streptomyces species it is a plant pathogen causing corky lesions to form on tuber and root crops as well as decreasing the growth of seedlings.

The genome contains a pathogenicity island containing the genes required for S. scabiei to infect plants, and which can be transferred between different species.

It can infect young seedlings of all plants, as well as mature root and tuber crops, but is most often associated with causing common scab of potato.

[4][5] In 1914 Hans Theodor Güssow renamed the species Actinomyces scabies, noting that Oospora was an incorrect classification since the disease was not caused by a fungus.

[5] In 1997 the name was changed to Streptomyces scabiei following a grammatical convention as set out in Rule 12c of the International Code of Nomenclature of Bacteria.

[8] The most widespread species other than S. scabiei are S. turgidiscabies and S. acidiscabies, which can be distinguished based on their morphology, the way they utilise food sources and their 16S RNA sequences.

[2] Unlike S. scabiei, S. acidiscabies is predominantly seed-borne rather than soil-borne and be suppressed using insecticides and nematicides, suggesting that microfauna play a role in its transmission.

[13] In 2003 three other species of Streptomyces that cause common scab symptoms were isolated in Korea and named S. luridiscabiei, S. puniciscabiei and S. niveiscabiei.

16 distinct strains have been isolated from tubers and based on a genetic analysis of them, they are most similar to S. griseoruber, S. violaceusniger, S. albidoflavus and S. atroolivaceus.

Defining characteristics of strains of S. scabiei are that they grow on the sugar raffinose, are unable to degrade xanthine and when grown on media containing the amino acid tyrosine, they produce the pigment melanin, the same chemical that gives humans their skin colour.

The lesions are typically brown, with a diameter of several millimetres but the size and colour can vary depending on environmental conditions.

subterranea and silver scurf and black dot caused by the fungi Helminthosporium solani and Colletotrichum coccodes respectively.

[28] All the genes required for thaxtomin biosynthesis are located on one part of the genome, termed the pathogenicity island, that is also found in S. acidiscabies and S. turgidiscabies[26] which is around 660 kb in length.

[8] They are neither organ or plant specific and if added to the leaves of various species cause them to die,[29] indicating that the target is highly conserved.

It is thought that S. scabiei cannot degrade cellulose itself and that instead it detects cellobiose that leaks through plant cell walls at areas where the roots are actively growing.

When the model plant, Arabidopsis thaliana is challenged by S. scabiei or thaxtomin A it produces the antimicrobial phytoalexin called scopoletin, which is known to accumulate in tobacco when it is infected by pathogens.

This leads to the bacteria growing more slowly and producing less thaxtomin A, thought to be linked to the repression of the nitric oxide synthase gene involved in its synthesis.

[29] Streptomyces scabiei can infect many plants, but is most commonly encountered causing disease on tuber and tap root crops.