Project description:To characterize the PTI response of tomato and the effect of the delivery of a subset of effectors, we performed an RNA-seq analysis of tomato Rio Grande prf3 leaves challenged with either the flgII-28 peptide or the following bacterial strains: Agrobacterium tumefaciens GV2260, Pseudomonas fluorescens 55, Pseudomonas putida KT2440, Pseudomonas syringae pv. tomato (Pst) DC3000, Pst DC3000 deltahrcQ-U deltafliC and Pst DC3000 deltaavrPto deltaavrPtoB. NOTE: Samples in SRA were assigned the same sample accession. This is incorrect as there are different samples, hence âSource Nameâ was replaced with new values. Comment[ENA_SAMPLE] contains the original SRA sample accessions.
Project description:The biocontrol agent Pythium oligandrum, which is a member of phylum Oomycota, can control diseases caused by a taxonomically wide range of plant pathogens, including fungi, bacteria, and oomycetes. However, whether P. oligandrum could control diseases caused by plant root-knot nematodes (RKNs) was unknown. We investigated a recently isolated P. oligandrum strain GAQ1, and the P. oligandrum CBS530.74 strain, for the control of RKN Meloidogyne incognita infection of tomato (Solanum lycopersicum L.). Initially, P. oligandrum culture filtrates were found to be lethal to M. incognita second-stage juveniles (J2s) with up to 84% mortality at 24 h after treatment compared to 14% in the control group. Consistent with the lethality to M. incognita J2s, tomato roots treated with P. oligandrum culture filtrates reduced the attraction of nematodes, and the number of nematodes penetrating the roots was reduced by up to 78%. In a greenhouse pot trial, P. oligandrum GAQ1 inoculation of tomato plants significantly reduced the gall number by 58% in plants infected with M. incognita. Notably, P. oligandrum GAQ1 mycelial treatment significantly increased tomato plant height (by 36%), weight (by 27%), and root weight (by 48%). Transcriptome analysis of tomato seedling roots inoculated with the P. oligandrum GAQ1 strain identified ~2,500 differentially expressed genes. The enriched GO terms and annotations in the up-regulated genes suggested modulation of plant hormone-signaling and defense-related pathways in response to P. oligandrum. In conclusion, our results support that P. oligandrum GAQ1 can serve as a potential biocontrol agent for M. incognita control in tomato. Multiple mechanisms appear to contribute to the biocontrol effect involving direct inhibition of M. incognita, potential priming of tomato plant defenses, and plant growth promotion.
Project description:To compare the genome-wide transcriptional effect of ABA and iSB09 in tomato plants, we performed RNA-seq analysis of mock-, 10 uM ABA- or 20 uM iSB09-treated plants. Differential gene expression analysis between mock- and ABA-treated or iSB09-treated seedlings was done with DESeq2 and genes with an absolute value of log2 fold change (log2FC) > 1 or (log2FC) < -1 and p-adjusted value (padj) < 0.05 were selected. iSB09 upregulated and downregulated genes represent a subset of the ABA-responsive genes, which reflects the activation of PYL1-like and PYL4-like ABA receptors in tomato seedlings. Additionally, to compare the genome-wide transcriptional effect of ABA and iCB in tomato plants, we performed RNA-seq analysis of mock-, 10 uM ABA- or 10 uM iCB-treated plants. Differential gene expression analysis between mock- and ABA-treated or iCB-treated seedlings was done with DESeq2 and genes with an absolute value of log2 fold change (log2FC) > 1 or (log2FC) < -1 and p-adjusted value (padj) < 0.05 were selected. iCB mimics ABA transcriptional response through activation of the three subfamilies of ABA receptors.
Project description:This study aimed to investigate the physiological and molecular responses of Solanum lycopersicum (tomato) to Phytophthora cinnamomi infection. The initial defense response in tomato seeds included the production of reactive oxygen species (ROS) and callose deposition. Screening of commercial tomato varieties revealed varying levels of susceptibility, with the variety Marmande exhibiting heightened vulnerability. Three days post-inoculation, Marmande showed increased expression of genes associated with ROS generation, and biosynthesis pathways for phenylpropanoids and flavonoids. Additionally, 850 genes related to cell wall remodeling, including those involved in lignin biosynthesis and pectin methyl esterase inhibitors (PMEIs), were significantly upregulated. Seven days post-inoculation, a stronger transcriptional response was observed, with activation of ethylene (ET) and jasmonic acid (JA) signaling pathways, while salicylic acid (SA) showed minimal activity. Metabolomic analysis of infected roots revealed elevated levels of metabolites linked to lycopene, flavonoids, and phenylpropanoids. Furthermore, infected roots exhibited a significant reduction in pectin levels, which was corroborated by in vitro assays showing zoospore-mediated pectin degradation. These results suggest that degradation of root pectin is a key mechanism facilitating zoospore invasion in susceptible tomato hosts. This study provides new insights into the molecular mechanisms underlying host-pathogen interactions and identifies potential targets for managing Phytophthora cinnamomi-induced diseases in crops.