The potential of endomycorrhizal fungi in controlling tomato bacterial wilt <i>Ralstonia solanacearum</i> under glasshouse conditions

Abstract

The impact of colonization by three mycorrhizal fungi on tomato bacterial wilt caused by Ralstonia solanaceraum was investigated. Three species of arbuscular mycorrhizal fungal (AMF) were tested (Glomus mosseae, Scutellospora sp. and Gigaspora margarita). Siginificant differences in tomato growth based on plant hieght was recorded between G. mosseae (125.25 cm) and all treatments. The combination of G. mosseae and R. solanacearum resulted in significantly taller tomato plants than G. margarita + R. solanacearum and Scutelospora sp.+ R. solanacearum. Shoot fresh and dry weight was higher in G. mosseae inoculated plants. No disease symptoms were observed in the combination treatment of G. mosseae and R. solanacearum. The plants treated with Scutellospora sp. showed low incidence of infection (105, 15%) at 15 and 20 days after inoculation, respectively. The combination of G. mosseae and R. solanacearum resulted in more increase in root morphology (root tips (434.75), root length (267.00 cm), root surface area (149.31 cm²), root volume (3.77 cm³), root fresh weight (4.75 g) and root dry weight (2.5 g). The treatment of G. mosseae + R. solanacearum was different significantly when compared to G. margarita and Scutellospora sp. + R. solanacearum treatments in all parameters considered. The highest number of AMF spores was recorded in G. mosseae treatment followed by Scutellospora sp. The concentration of N, P and K in G. mosseae + R. solanacearum treatment was significantly higher (N: 1.69; P: 0.51 and K: 1.65%) compared to G. margarita (N: 1.06 ; P: 0.11 and K: 1.02%) and Scutellospora sp., treatment (N: 1.48; P: 0.44 and K: 1.47%). Generally, the current findings has provided an evedance about the ability of AMF species to control bacterial wilt causal agents with significant differences between the species used.

Keywords: Bio-control, wilt disease, tomato, Glomus mosseae