Differences in host range, pathogenicity to potato cultivars and response to soil temperature among Streptomyces species causing common and netted scab in France

Abstract

The pathogenicity and ecology of some isolates representative of the four main Streptomyces species (S. scabies, S. europaeiscabiei, S. stelliscabiei and S. reticuliscabiei) identified as pathogenic to potato tubers were investigated. Three pathogenicity groups could be distinguished. Group 1 included all isolates of S. scabies, S. europaeiscabiei and S. stelliscabiei from common scab lesions of potato and other susceptible root crops. All these produced similar symptoms and were pathogenic to potato, carrot and radish. Group 2 included all isolates from S. reticuliscabiei netted scab lesions; they were pathogenic to both tubers and roots of only a few potato cultivars, and did not infect carrot or radish. Group 3 included three isolates of S. europaeiscabiei from netted scab lesions on cv. Bintje, which produced either common or netted scab symptoms depending on the potato cultivar or plant species. In an experiment on a few isolates from each of the three groups, held at various soil temperature regimes, the three from group 1 were most pathogenic at higher temperatures (20ЊC or 20/30ЊC), the two from group 2 were most pathogenic at a lower temperature (17ЊC). The group 3 isolate caused netted scab symptoms on susceptible cultivars at low temperatures (Յ 20ЊC) and deep-pitted lesions at higher temperatures. Since the groups identified differ in ecological requirements, it is important to adapt the control methods to the pathogenic species present in the soil.

Streptomyces species associated with common scab lesions of potatoes in South Africa

“…from Venezuelan soils. Isolates from netted scab in the Netherlands were positive for melanin production, and considered identical to S. scabiei (Bouchek-Mechiche et al 2000). Netted scab isolates that did not produce melanin were however also reported from Denmark and Sweden.…”

Phytotoxin produced by Streptomyces sp. causing potato russet scab in Japan

“…Finnish netted scab pathogen was also classified as S. aureofaciens (Kreuze et al 1999). Netted scab in France was induced by S. reticuliscabiei and some strains of S. europaeiscabiei (Bouchek-Mechiche et al 2000a, 2000b. S. reticuliscabiei and S. europaeiscabiei are closely related to S. turgidiscabies and S. scabies, respectively; and S. aureofaciens is distantly related to these species in 16S rRNA analysis (Song et al 2004).…”

Effect of chitosan and a biocontrol streptomycete on field and potato tuber bacterial communities

“…Common scab symptoms consist of superficial to deep corky lesions on the tubers. Methods used to control common scab include chemical treatments of seed potato tubers (Davis et al, 1976), irrigation (Adams and Lapwood, 1978), rotation strategies (Li et al, 1999), use of a tolerant cultivar (Bouchek-Mechiche et al, 2000), soil amendment with chitinous compounds (Vruggink, 1970;Beause´jour et al, 2003) and biological control with non-pathogenic streptomycetes (Liu et al, 1995;Ryan and Kinkel, 1997;Doumbou et al, 1998;Agbessi et al, 2003;Beause´jour et al, 2003). Recently, Beause´jour et al (2003) reported the use of a biological agent (Streptomyces melanosporofaciens Arcamone et al strain in combination with chitosan to control common scab.…”