Project description:Comparative transcriptome analysis was performed to study gene expression profiles in resistant (Yanyan 97, YY97, 25) and susceptible (Huanghuadajinyuan, HD, 36) tobacco in responding to Ralstonia solanacearum infection. Illumina sequencing yielded a total of 67,619,833,668 bases data, and about 223.99 M and 223.82 M raw reads for Hd and Yy97 plants, respectively. About 209.73 M and 209.18 M clean reads of Hd and Yy97 were mapped to reference genome via Hisat2, respectively. The ratio of mapped clean reads for eight libraries ranged from 93.92% to 96.67% (average: 95.9%). By comparing gene expression levels in Rs infected and control tobacco stems, we identified 15374 DEGs in Hd plants after Rs infection, which included 7220 up-regulated and 8154 down-regulated DEGs. We identified 2120 DEGs in Yy97 plants after Rs infection, which included 1794 up-regulated and 326 down-regulated DEGs.
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:Gene expression was measured in leaves from dark treated tobacco plants to investigate the changes associated with dark induced senescence.
Project description:Although Pseudomonas aeruginosa is an opportunistic pathogen that does not often naturally infect alternate hosts such as plants, the plant-P. aeruginosa model has become a widely recognized system for identifying new virulence determinants and studying pathogenesis of this organism. Here we examine how both host factors and P. aeruginosa PAO1 gene expression are affected in planta after infiltration into incompatible and compatible cultivars of tobacco (Nicotiana tabacum L.) Nicotiana tabacum has a resistance gene (N) against tobacco mosaic virus; and although resistance to PAO1 infection correlated to the presence of a dominant N-gene, our data suggests that it is not a factor in resistance against Pseudomonas. We did observe that the resistant tobacco cultivar had higher basal levels of salicylic acid, and a stronger salicylic acid response upon infiltration of PAO1. Salicylic acid acts as a signal to activate defense responses in plants, limiting the spread of the pathogen and preventng access to nutrients. It has also been shown to have direct virulence modulating effects on P. aeruginosa. We also examined host effects on the pathogen by analyzing global gene expression profiles of bacteria removed from the intracellular fluid of the two plant hosts. We discovered that the availability of micronutrients, particularly sulfate and Pi, are important factors in in planta pathogenesis, and that the amounts of these nutrients made available to the bacteria may in turn have an effect on virulence gene expression. Indeed, there are several reports suggesting that P. aeruginosa virulence is influenced in mammalian hosts by the availability of iron and by levels of O2. Keywords: comparative genomic hybridization, disease state analysis
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