Project description:To generate an efficient defense against begomovirus, we modulated the activity of the immune defense receptor NIK (NSP-Interacting Kinase) in tomato plants; NIK is a virulence target of the begomovirus NSP during infection. Replacing threonine-474 with aspartate (T474D) within the kinase activation loop promoted the constitutive activation of NIK-mediated defenses. This activation resulted in the down-regulation of translation-related genes and the suppression of global translation in T474D-overexpressing tomato lines. We also found that T474D-induced defense-related transcripts were associated with polysomes and immune proteins, which accumulated to detectable levels in T474D leaves. Consistent with these findings, T474D transgenic lines were tolerant to the tomato-infecting begomoviruses ToYSV and ToSRV. We propose that NIK mediates an anti-viral response via translation suppression and immune system induction.
Project description:To generate an efficient defense against begomovirus, we modulated the activity of the immune defense receptor NIK (NSP-Interacting Kinase) in tomato plants; NIK is a virulence target of the begomovirus NSP during infection. Replacing threonine-474 with aspartate (T474D) within the kinase activation loop promoted the constitutive activation of NIK-mediated defenses. This activation resulted in the down-regulation of translation-related genes and the suppression of global translation in T474D-overexpressing tomato lines. We also found that T474D-induced defense-related transcripts were associated with polysomes and immune proteins, which accumulated to detectable levels in T474D leaves. Consistent with these findings, T474D transgenic lines were tolerant to the tomato-infecting begomoviruses ToYSV and ToSRV. We propose that NIK mediates an anti-viral response via translation suppression and immune system induction. Global variation on gene expression induced by NIK expression and virus infection using total RNA from mock-inoculated and ToYSV-infected tomato wild-type plants, mock-inoculated and infected 35S::NIK1-4 overexpressing lines and mock-inoculated and infected 35S::T474D overexpressing lines. File map_itag23.csv correlates the ITAG 2.3 cDNA ID with the 21 bp reads in file Profiles_with_differential_expressions.csv.
Project description:We analyzed the global defense responses in common tobacco against a begomovirus Tomato yellow leaf curl China virus, an invasive whitefly species Middle East-Asia Minor 1, and their co-infestation. The transcripts of defense related genes were both overlapping and divergent in response to virus and whitefly.
Project description:Small RNA (sRNA)-guided RNA silencing is a critical antiviral defense mechanism employed by a variety of eukaryotic organisms. Although the induction of RNA silencing by bipartite and monopartite begomoviruses has been described in plants, the nature of begomovirus/betasatellite complexes remains undefined. We profiled Tomato yellow leaf curl China virus (TYLCCNV) and its associated betasatellite (TYLCCNB)-derived small RNAs (V-sRNAs and S-sRNAs) using Solexa-based deep sequencing to evaluate the role of betasatellites in V-sRNA modulation. Both sense and anti-sense V-sRNAs and S-sRNAs accumulated preferentially as 22 nucleotide species in infected Solanum lycopersicum and Nicotiana benthamiana plants, indicating that secondary siRNAs were triggered. High resolution mapping of V-sRNA and S-sRNA revealed heterogeneous distribution of V-sRNA and S-sRNA sequences across the TYLCCNV and TYLCCNB genomes. In TYLCCNV-infected S. lycopersicum or N. benthamiana and TYLCCNV and betaC1-mutant TYLCCNB co-infected N. benthamiana plants, the primary TYLCCNV targets were AV2 and the 5’ terminus of AV1. In TYLCCNV and betasatellite-infected plants, the number of V-sRNAs targeting this region decreased and the production of V-sRNAs increased corresponding to the overlapping regions of AC2 and AC3, as well as the 3’ terminal of AC1. betaC1 is the primary determinant mediating symptom induction and also the primary silencing target of the TYLCCNB genome even in its mutated form. In addition, the betasatellite affected the amount of V-sRNAs detected in S. lycopersicum and N. benthamiana plants. characterization of Tomato yellow leaf curl China virus and Tomato yellow leaf curl China betasatellite-derived small interfering RNAs from five cDNA libraries of two plant species
Project description:The associated files are mass spec data from HPLC mixed-bed ion exchange column fractions. Sample loaded was a native extract of tomato leaves.
Project description:Tomato curly stunt virus (ToCSV) is a monopartite begomovirus infecting tomatoes in South Africa, with sequence similarity to tomato yellow leaf curl virus (TYLCV). While there are numerous reports on the mechanism of TYLCV resistance in tomato, the underlying mechanisms in the tomato-ToCSV pathosystem is still relatively unknown. The main aim of this study was to investigate and compare the global methylation profile of ToCSV in two near-isogenic tomato lines, one with a tolerant phenotype (T, NIL396) and one with a susceptible phenotype (S, NIL395). Bisulfite conversion and PCR amplification, coupled with a next-generation sequencing approach, were used to elucidate the global pattern of methylation of ToCSV cytosine residues in T and S leave tissue at 35 days post-infection (dpi). The extent of methylation was more pronounced in tolerant plants compared to susceptible plants in all sequence (CG, CHG and CHH) contexts, however, the overall methylation levels were relatively low (<3%). Notably, a significant interaction (p < 0.05) was observed between the viral genomic region and susceptible vs. tolerant status for CG methylated regions where it was observed that the 3'IR CG methylation was significantly (p < 0.05) higher than CG methylation of other genomic regions in tolerant and susceptible plants. Additionally, statistically significant (EdgeR p < 0.05) differentially methylated cytosines were located primarily in the genomic regions V2/V1 and C4/C1 of ToCSV. The relative expression, using RT-qPCR, was also employed in order to quantify the expression of various key methylation-related genes, MET1, CMT2, KYP4/SUVH4, DML2, RDM1, AGO4 and AGO6 in T vs. S plants at 35dpi. The differential expression between T and S was significant for MET1, KYP4/SUVH4 and RDM1 at p<0.05 which further supports more pronounced methylation observed in ToCSV from T plants vs. S plants. While this study provides new insights into the differences in methylation profiles of ToCSV in S vs. T tomato plants, further research is required to link tolerance and susceptibility to ToCSV.