Project description:Phytophthora cinnamomi Rands is a cosmopolite and phyllophagous pathogen of woody plants which during the last couple of centuries has spread all over the world from its center of origin in Southeast Asia. Despite Chinese cork tree (Quercus variabilis Blume) forests native to Asia being generally healthy, the populations of cork trees (Quercus suber L.) in Europe have been decimated by P. cinnamomi. The present study tries to identify the differences in the early proteomic and metabolomic response of these two tree species that lead to their contrasting susceptibility to P. cinnamomi attack. By using micropropagated clonal plants, we tried to minimize the plant-to-plant differences in the defense response that is maximized by the high intraspecific genetic variability inherent to the Quercus genus. The evolution on the content of Phytophthora proteins in the roots during the first 36 hours after inoculation suggest a slower infection process in Q. variabilis plants. These plants displayed a significant decrease in sugars in the roots, together with a downregulation of proteins related to carbon metabolism. In the leaves, the biggest changes in proteomic profiling were observed 16 hours after inoculation. and included increased abundance of peroxidases, superoxidedismutases and gluthatione S-transferases in Q. variabilis plants, which probably aided its resistance against P. cinnamomi attack.
Project description:For the filamentous cyanobacterium Anabaena variabilis to grow without combined nitrogen, certain cells differentiate into heterocysts that fix N2, while vegetative cells perform photosynthesis. Much remains unknown on how heterocysts differ from vegetative cells in terms of carbon and energy metabolisms. Microarrays were used to investigate gene transcription patterns in vegetative cells, heterocysts, and filaments of N2-fixing phototrophic, mixotrophic, and heterotrophic cultures. Hybridizations used NimbleGen expression array chips (Product no. A4385-00-01, platform accession no GPL15883) designed against the 5,657 ORFs encoded in the A. variabilis genome (GenBank accession no. CP000117). Each ORF was represented by seventeen 60-mer oligonucleotides. Each oligonucleotide was present in four internal replicates. The twenty-seven microarray data files were normalized against each other. Expression array data were analyzed using ArrayStar 3.0 (DNASTAR, Madison, WI).
