Project description:Tomato is one of the most important crops for human consumption. Unfortunately, its production is affected by diseases caused by pathogens such as the actynomicete Clavibacter michiganensis subsp. michiganens (Cmm). This pathogen is the causal agent of the bacterial canker of tomato, considered one of the most devastating tomato diseases. To date, there are not resistant varieties of commercial tomato against Cmm. However, there are wild tomato species resistant to Cmm. Using massive sequencing, we obtained the transcriptomes of the wild tomato species Solanum arcanum LA2157 and the commercial tomato Solanum lycopersicum cv. Ailsa Craig at 8 and 24 hours after Cmm challenge. We identified potential tomato tolerance-related genes by three approaches: mapping the reads to S. lycopersicum reference genome SL3.0, performing a semi de novo transcriptome assembly and a de novo transcriptome assembly. Some functional groups such as oxylipin biosynthetic process response to wounding, response to cytokinin among others, were enriched in both tomato species, suggesting a similar response, however, genes that encode proteins such as the Polyphenol oxidase E, Ankyrin and Leucine Rich Repeat receptors were overexpressed mainly in the wild tomato species, suggesting a possible role in the defense response. Here, we uncovered new candidate genes potentially related to bacterial canker tomato defense.
2020-06-13 | GSE152330 | GEO
Project description:Genome sequencing and assembly of biological control agents
| PRJNA1024950 | ENA
Project description:Isolation of Bacillus velezensis XZ3-6 against apple canker, and transcriptome analysis uncover the biological control mechanism
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:The global imperative to enhance crop protection while preserving the environment has increased interest in the application of biological pesticides. Bacillus thuringiensis (Bt) is a Gramm-positive bacterium that can produce nematicidal proteins and accumulate them in parasporal crystals. Root-knot nematodes are obligate root plant parasitic which are distributed worldwide, causing severe damages to the infested plants and, consequently, large yield reductions. In this work, we have evaluated the toxicity of the crystal proteins Cry5, Cry21, App6, and Xpp55 against two root-knot nematodes belonging to the Meloidogyne genus (M. incognita and M. javanica). The results show that all four proteins, when solubilized, were highly toxic for both nematode species. To check the potential of using Bt strains producing nematicidal crystal proteins as biopesticides to control plant parasitic nematodes in the field, in planta assays were conducted, using two wild Bt strains which produced Cry5 or a combination of App6 and Cry5 proteins. The tests were carried out with cucumber or with tomato plants infested with M. javanica J2, subjected to irrigation with spore+cristal mixtures of the respective strains. The results showed that the efficacy of the nematicidal activity was plant-dependent, as Bt was able to reduce emerged J2 in tomato plants but not in cucumber plants. In addition, the toxicity observed in the in planta assays was much lower than expected, highlighting the challenge of the crystal proteins to exert their toxicity. This emphasizes the delivery of the Bt proteins as crucial for its use to control root-knot nematodes.
Project description:Experiment evaluating aplicability of PlasTi-microarray for cross-species hybridization studies. PlasTi-microarray is a tiling oligonucleotide microarray originally designed for cucumber plastome analysis.Chloroplast RNA from Arabidopsis, tomato and spinach leaves was extracted, labelled and hybridized to PlasTi-microarray with the cucumber samples labelled with the second dye as a control. For each species, one biological sample and one technical replicate (labelled in a dye-swap orientation) were analyzed, resulting in two microarray hybridizations per species and six microarrays (a-f) in total.
Project description:Clavibacter michiganensis subsp. michiganensis is an important Gram-positive phytopathogenic bacteria that causes bacterial wilt and canker in tomato. The genome of the type strain, NCPPB382, has been sequenced and annotated, however comparative genomics suggests that certain regions are under- or misannotated. In order to improve the genome annotation, we have undertaken a proteogenomic study of this important pathogen. Samples were grown in culture and the proteome of the pellet and supernatant were analyzed separately using shotgun HPLC-MS/MS. These proteomics datasets were analyzed and a number of missing gene were found and a number of existing gene calls were modified.