ABSTRACT: Quantitative transcriptional changes associated with chlorosis severity in mosaic leaves of tobacco plants infected with the Cucumber mosaic virus
Project description:M-CMV-infected N. tabacum plants with six symptoms (vein clearing, mosaic, chlorosis, partial green recovery, complete green recovery and secondary mosaic) were analyzed by LC-MS & GC-MS. In addition, the pathogenesis biomarker might be found by this untargeted global metabolomic analysis.
Project description:Gene expression was measured in leaves from dark treated tobacco plants to investigate the changes associated with dark induced senescence.
Project description:In this study, we compared transcriptomes in chlorotic tissues infected with wild type CMV or two CP mutants (129A and 129Q) with diverse chlorosis severity. Differentially expressed genes analysis showed that the CMV inoculation appeared to have similar effects on transcriptional expression profiles of the symptomatic chlorotic tissues and only the magnitude of expression differed among CMVs. Gene ontology analysis with biological process and cellular component terms revealed that many nuclear genes related to abiotic stress responses, including cadmium, heat, cold, and salt, were up-regulated while chloroplast- and photosynthesis-related genes (CPRGs) were down-regulated in the chlorotic tissues. Interestingly, down-regulation level of CPRGs was correlated with the chlorosis severity. The expression difference genes (DEGs) between mock-inoculated healthy tissues and CMV-inoculated chlorotic tissues in mosaic leaves of tobacco plants were examined by the comparison on one-colour microarray data. Three biological replicates per each treatment were used in this experiment.
Project description:CP12 is a small nuclear encoded chloroplast protein that has been shown to form a complex with the Calvin cycle enzymes, PRK and GADPH. We have taken an antisense approach in order to address the importance of this regulatory protein on carbon assimilation. Transgenic Nicotiana tabacum cv. Samsun with reduced levels of the CP12 protein, produced by leaf disc transformation with a full length tobacco CP12 cDNA, regulated by the cauliflower mosaic virus 35S promoter. Agrobacterium tumefaciens-mediated transformation and selection on kanamycin produced primary transformants whose progeny segregate for severity of the antisense CP12 phenotype. Because of the impact of the antisense reductions in CP12 on carbon assimilation, these plants have abnormal morphology of leaves, floral organs, greatly reduced fertility and markedly slower growth rates. Our hypothesis is that the phenotype is exposing the regulatory nature of the CP12 protein. Intermediates leaving the Calvin cycle are essential for the synthesis of hormones and perturbation of hormone balances is a potential source of the morphological and development effects observed in the CP12 antisense plants. Our objective is to understand the CP12 phenotype by identifying changes in gene expression occurring at key stages in the life cycle of the CP12 antisense plants. CP12 antisense and wild type control plants for microarray analysis were germinated in a growth chamber in agar medium with 1% sucrose and 1/2 strength MS; with a 16 h light/8 h dark cycle at 25°C. At 20 days plants were transferred to a controlled environment greenhouse and grown in Fisons Levington F2 compost at 25°C, with light levels above 500 umol m-2 s-1 ;using supplementary lighting in a 16 h light/8 h dark cycle. 3 independent sets of plants (both wild type and CP12 antisense) were grown for preparation of three independent biological replicate RNA samples. RNA was extracted according to the TIGR protocol from plants in the early in all samples. Keywords: Direct comparison
Project description:Transgenic tobacco (Nicotiana tabacum) expressing Caenorhabditis elegans cell death genes, Ced4 and Ced3, show evidence suggesting such expressions protect the plants from infestation by the plant parasitic nematode Meloidogyne incognita. Although positive results have been correlated with the gene expressions (data in preparation for publication; a draft of the publication can be provided upon request), the mechanism by which the nematode protection is manifested is not clearly understood. One possibility is that the C. elegans cell death proteins produced by the transgenic plants are being ingested and incorporated into the nematode’s own cell death pathway, leading to their demise. Alternatively, it is also possible that expression of the C. elegans cell death genes promotes the endogenous resistance genes of the plant, leading to nematode resistance. We want to test the later hypothesis by conducting a reference design microarray experiment to establish the expression profile of Ced3, and Ced4 homozygous plants and Ced3xCed4 double heterozygous plants in comparison with wild-type tobacco plants. If the hypothesis is correct, we expect to detect increased expression of pathogenicity-related genes in the transgenic plants. Furthermore, characterization of the expression profiles in these transgenic plants will provide us directionality for our future research on the elucidation of this resistance mechanism. Keywords: Reference design
Project description:In this study we used vascular specific promoters and a translating ribosome affinity purification strategy to identify phloem-associated translatome responses to infection by tobacco mosaic virus (TMV) in the systemic host Nicotiana benthamiana. Three different promoter:FLAG-RPL18 lines were used. These included two phloem specific promoters (pSUC2 and pSULTR2;2) as well as the more ubiquitously expressed cauliflower mosaic virus 35S promoter (p35S). Immunopurification of ribosome-mRNA complexes was accomplished by the method described in Reynoso et al. (Plant Functional Genomics: Methods and Protocols, 185-207; 2015). The dataset includes samples from the leaves of 5-week-old plants inoculated with TMV (1 mg/mL) or mock inoculated with sterile water.