Disease suppressive soils are important for managing soil-borne diseases that cannot be controlled with chemicals. One such disease is the potato common scab caused by Streptomyces species. Suppressiveness against common scab can develop spontaneously in fields where potato is grown for years without interruption, and this has been attributed to non-pathogenic Streptomyces strains. Streptomyces spp. have been used as inoculants in biological control, but their long-term effects have gained less attention. In our previous studies, a non-pathogenic Streptomyces strain (Str272) isolated from a potato common scab lesion suppressed common scab in field trials lasting over 5 years. In this study, bacterial communities in the tuberosphere i.e. in the soil adjacent to potato tubers, were analysed by next generation sequencing (NGS). The aim was to compare bacterial communities in untreated control plots to those in which seed tubers were treated with Str272 in one or several growing seasons. Str272 applications increased soil bacterial diversity and affected the bacterial composition in the potato tuberosphere. The most pronounced differences were observed between the untreated control and the treatments in which the antagonist had been applied in three or four consecutive years. The differences remained similar until the following growing season. Bacterial composition after repeated antagonist applications was associated with lower common scab severity. The antagonist applications had no or only slight effect on the number or abundance of OTUs belonging to Actinobacteria or Streptomyces, and no differences in quantities of pathogenic Streptomyces populations were detected by qPCR. This indicates that suppression of common scab by Str272 may not be based on direct effect on the common scab pathogens but is more likely to be associated with the alterations of the soil bacterial community. The most abundant bacteria phyla in the potato tuberosphere were Actinobacteria, Proteobacteria and Acidobacteria. However, the OTUs responding greatest to the antagonist treatments belonged to Bacterioidetes and Gemmatimonadetes. Results indicate that repeated applications of Str272 can change the bacterial community in the potato tuberosphere and lead to development of soil that is suppressive against potato common scab for several growing seasons after the last application.

疾病抑制土壤对于控制无法用化学品控制的土壤传播疾病很重要。一种这样的疾病是由链霉菌属物种引起的马铃薯常见痂病。在马铃薯连续多年生长的田地中，对常见痂病的抑制作用可以自发产生，这归因于非致病性链霉菌菌株。链霉菌属 已被用作生物防治中的接种剂，但其长期影响较少受到关注。在我们之前的研究中，一种非致病性链霉菌在持续超过 5 年的田间试验中，从马铃薯常见疮痂病病灶中分离出的菌株 (Str272) 抑制了常见的疮痂病。在这项研究中，通过下一代测序 (NGS) 分析了块茎中的细菌群落，即与马铃薯块茎相邻的土壤中的细菌群落。目的是将未经处理的对照地块中的细菌群落与在一个或几个生长季节中用 Str272 处理种子块茎的地块中的细菌群落进行比较。Str272 的应用增加了土壤细菌多样性并影响了马铃薯块茎中的细菌组成。在未处理的对照和连续三四年应用拮抗剂的处理之间观察到最显着的差异。直到下一个生长季节，差异仍然相似。重复应用拮抗剂后的细菌成分与较低的常见痂严重程度相关。拮抗剂应用对属于的 OTU 的数量或丰度没有影响或只有轻微影响通过 qPCR 检测到放线菌或链霉菌，并且致病性链霉菌种群的数量没有差异。这表明 Str272 对常见痂病的抑制可能不是基于对常见痂病病原体的直接影响，而是更可能与土壤细菌群落的改变有关。马铃薯块茎中最丰富的细菌门是放线菌、变形菌和酸菌。然而，对拮抗剂治疗反应最大的 OTU 属于拟杆菌属和Gemmatimonadetes。 结果表明，重复施用 Str272 可以改变马铃薯块茎中的细菌群落，并导致在最后一次施用后的几个生长季节形成对马铃薯普通疮痂病具有抑制作用的土壤。