Microbial interactions in tomato solanum iycopersicum for health, growth, and pathogen defence

Abstract

PhD ThesisSolanum lycopersicum is an important vegetable high in vitamin A and C and minerals such as phosphorus, iron and high in lycopene and beta-carotene. It is considered the favourite in the food processing and cosmetics industries. S. lycopersicum current global production is concentrated in the United States of America, China, and India. The production of S. lycopersicum depends on the application of chemical fertiliser; however, ecological damages caused by chemical fertiliser far outweigh its benefits. Thus, there is a need to initiate and adopt eco-friendly cultivation of S. lycopersicum using vertically transmitted endophytes. In this study, different strains of vertically transmitted endophytic bacteria were isolated from eight different cultivars of S. lycopersicum. The findings show that vertically transmitted endophytes are host specific and display various phenotypes that produce diverse metabolites with different concentrations. It also demonstrated that treated S. lycopersicum under fertilised microbial communities performed significantly better than those under the manure microbial community, untreated microbial community, and the control tank. The finding also shows that vertically transmitted endophytes in the S. lycopersicum failed to stimulate interaction between S. lycopersicum and its surrounding soil microbial communities, which promotes plant growth, increase chlorophyll content, increase fresh and dried biomass of the plant. Our result further demonstrated no significant difference when the isolated vertically transmitted endophytes Bb-B-1 was inoculated on S. lycopersicum under the optimum nutrient condition and deprived nutrient condition. Finally, the study demonstrates that microbial communities from fertilised treated soil, manure treated soil, and untreated microbial communities are not involved in inducing or suppressing Auxin, LelRT1, FER, FROS2 and LeNRT2;3 genes in S. lycopersicum. It further shows that the S. lycopersicum vertically transmitted endophytes are not involved in regulating these genes. Whilst no significant result to demonstrate the possible role of vertically transmitted endophytes the study demonstrated that S. lycopersicum vertically transmitted endophytes are host specific and display various phenotypes that produce diverse metabolites with different concentrations. Further investigation is required to focus on the isolated vertically transmitted endophytes precisely to understand their possible roles in the plant host. Additional studies investigating the role of different microbial communities on the host plant required more time to monitor the suitable duration needed by the microbial communities to be established in the new environment.PTDF Nigeri