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:RKNs are economically most damaging, obligate sedentary endoparasites that form giant cells within host roots to obtain nutrition and complete their life cycle. We report genome-wide identification of miRNAs from both host and RKN using RKN-infected susceptible tomato roots through high-throughput sequencing. Eleven small RNA libraries were made from five disease development stages, their five corresponding uninfected development stages and uninfected development stage 0. A total of 52 conserved miRNAs, 4 variants of conserved miRNAs and 281 novel miRNAs of host were identified. A significantly upregulated expression of majority of the miRNAs was observed during susceptible response and downregulated expression during resistance response through qRT-PCR. The miRNA targets were predicted and validated through 5’RLM-RACE. Furthermore, correlation between the expression profile of selected conserved miRNAs viz., miR164, miR156, miR396, miR159, and novel Sly_miRNA996 with their target transcription factors viz., NAC, SBP, GRF1, GAMYB-like, and MYB-like, respectively was also determined. This study suggests a potential role of host miRNAs in regulating transcription factor genes involved in plant developmental processes and defense responses during RKN infection. Additionally, 328 RKN miRNAs including 38 conserved miRNAs, 106 novel miRNAs, and 184 candidate novel miRNAs were identified from same dataset. The differential expression of conserved and RKN-specific miRNAs at different development stages of nematode in tomato roots suggests their probable role during nematode development and adaptation to parasitic behavior. This is the most comprehensive study reporting the identification and characterization of miRNAs from both tomato and RKN in five different disease development stages under soil grown conditions and their potential roles during RKN infection in tomato roots.
Project description:HsfA2 controls the activity of developmentally and stress-regulated heat stress protection mechanisms in tomato male reproductive tissues
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 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.