부산대학교 도서관

Seeds carry a complex population of pathogenic and non-pathogenic bacteria, which may have synergistic or antagonistic effects on each other and also affects their interaction with hosts. Pseudomonas syringaepv. syringae(Pss) and Xanthomonas translucens(Xt) are two well-known phytopathogenic bacteria that colonize wheat seeds and cause specific symptoms of the disease on the plant. The present study aims to determine Psscommunity composition in wheat seeds sampled from different areas of Iran causing bacterial leaf streak disease (BLS) and investigate the effects of Pssstrains that are located on/in wheat seeds on the severity of BLS disease caused by Xt. Culture-based and molecular methods detected Pssstrains in epiphytic and endophytic status and X. translucenspv. cerealisas an epiphytic pathogen from all sampled wheat seeds. Sequencing analysis of the 16S rRNA gene revealed no significant variations between Pssstrains. Moreover, we found that some Pssstrains strongly promoted BLS disease severity index. This was increased up to 6.11 and 5.62 times after seed treatment by epiphytic Pssstrain Ais 153 and endophytic strain Ais 170, respectively. The Pssstrains have different ranges of autoaggregation ability and coaggregation with Xt. No significant correlation was found between the synergistic effects of Pssstrains and their aggregation ability as a crucial step for bacterial interaction with each other and the host plant. Altogether, our results show the role of complex interactions of pathogenic bacteria in the emergence of seed-borne diseases. Understanding these interactions will help develop new strategies for bacterial disease management.