title: Transcriptional profile of tomato roots exhibiting Bacillus thuringiensis-induced resistance to Ralstonia solanacearum.
abstract: Activation of SA-dependent signaling pathway and suppression of JA-dependent signaling pathway seem to play key roles inB. thuringiensis-induced resistance toR. solanacearumin tomato plants. Bacillus thuringiensis, a well-known and effective bio-insecticide, has attracted considerable attention as a potential biological control agent for the suppression of plant diseases. Treatment of tomato roots with a filter-sterilized cell-free filtrate (CF) of B. thuringiensis systemically suppresses bacterial wilt caused by Ralstonia solanacearum through systemic activation of the plant defense system. Comparative analysis of the expression of the Pathogenesis-Related 1(P6) gene, a marker for induced resistance to pathogens, in various tissues of tomato plants treated with CF on their roots suggested that the B. thuringiensis-induced defense system was activated in the leaf, stem, and main root tissues, but not in the lateral root tissue. At the same time, the growth of R. solanacearum was significantly suppressed in the CF-treated main roots but not in the CF-treated lateral roots. This distinct activation of the defense reaction and suppression of R. solanacearum were reflected by the differences in the transcriptional profiles of the main and lateral tissues in response to the CF. In CF-treated main roots, but not CF-treated lateral roots, the expression of several salicylic acid (SA)-responsive defense-related genes was specifically induced, whereas jasmonic acid (JA)-related gene expression was either down-regulated or not induced in response to the CF. On the other hand, genes encoding ethylene (ET)-related proteins were induced equally in both the main and lateral root tissues. Taken together, the co-activation of SA-dependent signaling pathway with ET-dependent signaling pathway and suppression of JA-dependent signaling pathway may play key roles in B. thuringiensis-induced resistance to R. solanacearum in tomato.
authors.forename: Hideki
authors.initials: H
authors.lastname: Takahashi
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakaho
authors.forename: Takeaki
authors.initials: T
authors.lastname: Ishihara
authors.forename: Sugihiro
authors.initials: S
authors.lastname: Ando
authors.forename: Takumi
authors.initials: T
authors.lastname: Wada
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kanayama
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Asano
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Yoshida
authors.forename: Seiya
authors.initials: S
authors.lastname: Tsushima
authors.forename: Mitsuro
authors.initials: M
authors.lastname: Hyakumachi
mesh_terms: D001413:Bacillus thuringiensis / Q000502:physiology*; D002474:Cell-Free System; D060467:Disease Resistance / Q000235:genetics*; D015536:Down-Regulation / Q000235:genetics; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D018551:Solanum lycopersicum / Q000235:genetics*; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology* / Q000382:microbiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D043368:Ralstonia solanacearum / Q000254:growth & development / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics; D013997:Time Factors; D015854:Up-Regulation / Q000235:genetics
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger