Project description:Cd levels in the shoots, as well as in the roots were unexpectedly reduced in 35S:AtHMA4-expressing tobacco. Obtained results indicate that in the generation of the Cd-related phenotypes of transgenic plants substantial modifications of the host plant transcriptome was involved. Microarray based analysis was performed to compare expression profiles of the roots from tobacco expressing 35S-AtHMA4 with the wild-type (WT) plants, which were grown in the presence of 0.25 µM Cd. An effort was undertaken to understand which processes were modified in tobacco as a result of the expression of 35S:AtHMA4, which lead to decreased Cd uptake and lower accumulation in the shoots. Knowing underlying mechanisms is important for developing strategies to grow low cadmium tobacco.
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: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 27 hybs total
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:Gene expression was measured in leaves from dark treated tobacco plants to investigate the changes associated with dark induced senescence.
Project description:The number of known proteins associated with plant lipid droplets (LDs) is small compared to other organelles. Many questions of LD biosynthesis and degradation remain open, also due to lack of candidate LD proteins whose characterization could help to elucidate their function in those processes. We performed a proteomic screen on LDs isolated from Nicotiana tabacum pollen tubes. Proteins that were highly enriched in the LD fraction compared to the total or cytosolic fraction where verified for LD localization via transient expression in tobacco pollen tubes. We also compared the isoforms of typical LD proteins found in the pollen tubes on a qualitative level to the isoforms found in tobacco seeds.
Project description:Two tobacco transgenic lines over-expressing grapevine polygalacturonase-inhibiting protein (Vvpgip1) vs. WT tobacco under normal growth conditions