Physio-biochemical, molecular characterization, and phage susceptibility of Ralstonia pseudosolanacearum associated with tomato (Solanum lycopersicum) and eggplant (Solanum melongena)

Abstract

Abstract. Nurdika AAH, Arwiyanto T, Sulandari S. 2022. Physio-biochemical, molecular characterization, and phage susceptibility of Ralstonia pseudosolanacearum associated with tomato (Solanum lycopersicum) and eggplant (Solanum melongena). Biodiversitas 23: 5149-5158. Ralstonia solanacearum is a plant pathogen that causes bacterial wilt diseases in various plant species. The high diversity of these bacteria strains is the basis for their grouping into the R. solanacearum species complex (RSSC). RSSC associated with tomato and eggplant in Indonesia are commonly known as R. solanacearum. It is necessary to characterize R. solanacearum which infects tomatoes and eggplant according to the latest classification. The high diversity of strains also affects their susceptibility to bacteriophages as host-specific biocontrol agents. This research was conducted by characterizing R. solanacearum isolates from different locations based on their physio-biochemical properties, biovar, virulence, phylotype, sequevar, and susceptibility to 12 bacteriophage isolates. The phylotype identification was carried out using multiplex polymerase chain reaction with several specific primers for R. solanacearum. Amplification and sequencing based on the egl gene region were carried out to determine the sequevar of R. solanacearum isolates. As a result, isolates RS18, RS19, RS23, and RS24 had morphological, physio-biochemical, and biovar characteristics according to Ralstonia pseudosolanacearum phylotype I, biovar 3. The two most virulent isolates, RS19 and RS24 were identified as sequevar 14. RS19 and RS24 isolates were susceptible to 7 of the 12 bacteriophage isolates used in this study. Variations of bacteriophage isolates resulted in different plaque morphology which could be attributed to R. pseudosolanacearum susceptibility and bacteriophage virulence.

Morphological and Biochemical Characterization of Strains of Ralstonia solanacearum, Causal Agent of Bacterial Wilt in Tomatoes in Cameroon and Screening of Virulent Strains

“…The Kovacs oxidase test differentiated isolates tested with all isolates producing a dark purple color within 15-30 seconds indicating that they were aerobic bacteria [30]. Furthermore, the arginine test was negative because of the inability of the bacteria to degrade arginine, results also reported by Rahman et al [46] and Nurdika et al [47] during the biochemical characterization of R. solanacearum isolated from the eggplant, tomato and potato.…”

“…R. solanacearum may have triggered a hypersensitivity reaction in tobacco leaves. Indeed, this bacterium has an HR III type secretion system (T3SS), this secretion mechanism plays a role in the pathogenesis process which can trigger a hypersensitivity reaction [36,47]. All isolates in the area forest with monomodal rainfall were of race 1, it is present on all continents, except Europe [54,55].…”