Project description:Leaf mold disease caused by Cladosporium fulvum is a major disease in cultivated tomato plants and affects global tomato production. Some Cf genes, of which Cf-16 is an effective gene for resisting tomato leaf mold, are associated with leaf mold resistance; however, the molecular mechanism is largely unknown. We used comparative transcriptome analysis of C. fulvum-resistant (cv. Ontario7816, including the Cf-16 gene) and C. fulvum-susceptible (cv. Moneymaker) tomato lines to identify differentially expressed genes (DEGs) at 4 and 8 days postinfection with C. fulvum. Our results provide new insights into the resistance response mechanism of Cf genes to C. fulvum, especially the unique characteristics of Cf-16 in response to C. fulvum infection.
Project description:In response to biotic stress, plants produce suites of highly modified fatty acids that bear unusual chemical functionality. Despite their chemical complexity and proposed roles in pathogen defense, little is known about the biosynthesis of these decorated fatty acids in plants. Falcarindiol is a prototypical acetylenic lipid present in carrot, tomato, and celery that inhibits growth of fungi and human cancer cell lines. Using a combination of untargeted metabolomics and RNA sequencing, we discovered a biosynthetic gene cluster in tomato (Solanum lycopersicum) that is required for the production of falcarindiol in response to an adapted fungal pathogen, Cladosporium fulvum. By reconstituting the initial biosynthetic steps in a heterologous host (Nicotiana benthamiana) and generating transgenic pathway mutants in tomato, we demonstrate a direct role for three genes in the cluster in falcarindiol biosynthesis. This work reveals a mechanism by which plants sculpt their lipid pool in response to pathogens, and provides critical insight into the complex biochemistry of alkynyl lipid production.
Project description:Comparative transcriptome analysis between resistant and susceptible tomato lines uncovers the response mechanism of Cf-16-mediated resistance to Cladosporium fulvum
Project description:Heterologous expression of the fungal pathogen Cladosporium fulvum Avr2 in Arabidopsis plants. Experiment Overall Design: Samples used for microarray analyses were replicated three times in independent experiments and each replication consisted of 10 Avr2-expressing Arabidopsis plants and 10 Col-0 plants grown for four weeks under standard greenhouse conditions
Project description: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) [PR-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 root tissue but not in the CF-treated lateral root tissue. 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 the CF-treated main root tissue, but not CF-treated lateral root tissue, 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 plants. Gene expression was measured in main and lateral root tissues of tomato treated with Bacillus thuringiensis or distilled water-treated control at 48 hours after treatment. Two independent experiments were performed at each tissue (main root or lateral root tissue) for each treatment (Bacillus thuringiensis or distilled water control).
Project description: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) [PR-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 root tissue but not in the CF-treated lateral root tissue. 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 the CF-treated main root tissue, but not CF-treated lateral root tissue, 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 plants.