Project description:Jasmonic acid (JA) is a fatty-acid derived signaling molecule that regulates a wide variety of plant developmental and stress-related responses. We identified a jasmonate-insensitive1 (jai1) mutant of tomato that is defective in the LeCOI1 gene, which plays an essential role in induced resistance of tomato to a broad spectrum of pests, and is also required for maternal control of seed and fruit development. The present study is aimed at identifying genes involved in two JA-signaled processes that have not been studied in other plants. The first specific aim is to identify the set of JA/COI1-regulated genes in tomato reproductive tissues, with emphasis on genes expressed in maternal tissues. We hypothesize that JA/COI1 signaling regulates maternal processes that nurture the developing embryo and seed. The second aim of the study is to identify JA/COI1-regulated genes that are specifically expressed in tomato roots. Although it has been shown that JA promotes root defenses against various pests, virtually nothing is known about the JA-regulated transcriptome in roots. Tomato (Solanum lycopersicum) cv Micro-Tom wild-type and jai1 seed were grown in peat pots and maintained in growth chambers. To identify COI1-regulated genes in reproductive tissues, flower buds, open flowers and immature fruit at 7 and 17 days post-pollination were collected from 8 to 10 week old plants. To identify COI1-regulated genes in roots, 3 week old plants were exposed to exogenous JA by a single soil drench with 0.1mM JA, and roots were collected after 1, 6, 12 and 24 hours. Plants treated with water were used for the 0hr time point. All tissue was snap-frozen in liquid nitrogen, and RNA was extracted and analyzed as described in the TIGR Potato Microarray protocol (phenol method). Three biological replicates were collected for this study. Keywords: Direct comparison
Project description:To investigate how JA regulates Al-induced inhibition of root growth, a transcriptional analysis through RNAseq was performed by comparing the coi1-2 mutant and WT plants in the presence or absence of Al. In the absence of Al, 149 and 147 genes were up- and down-regulated, respectively, at least 2-fold in the roots of the coi1-2 mutant and WT plants. In the presence of Al, 1747 and 5838 genes were up- and down-regulated, respectively, in the roots of WT plants, while 1449 and 3773 genes were up- and down-regulated, respectively in the coi1-2 mutant. While the comparison of the Al-exposed coi1-2 mutant and WT plants reveals that totally 1187 genes were up-regulated and only 197 genes were down-regulated at least 2-fold.
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:HsfA2 controls the activity of developmentally and stress-regulated heat stress protection mechanisms in tomato male reproductive tissues
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: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:Pathogens target phytohormone signalling pathways to promote disease. Plants deploy salicylic acid (SA) mediated defences against biotrophs. Pathogens antagonise SA immunity by activating jasmonate signalling, e.g. Pseudomonas syringae pv. tomato DC3000 produces coronatine (COR), a jasmonate (JA) mimic. This study found unexpected dynamics between SA, JA and COR and co-operation between JAZ jasmonate repressor proteins during DC3000 infection. JA did not accumulate until late in the infection process and was higher in leaves challenged with coronatine deficient P. syringae or in the more resistant JA receptor mutant coi1. JAZ regulation was complex and coronatine alone was insufficient to sustainably induce JAZs.