The Role of RNAi in Downregulation of Physcomitrella Patens Defense Genes and the Preliminary Steps of PEG Mediated Transformation of Mosses

When attacked by a pathogen, the moss Physcomitrella patens will undergo both a hypersensitive response (HR) as well as a systematic acquired resistance (SAR) response. The SAR response turns on genes that ready the plant for future pathogen attacks. The hormone jasmonic acid (JA) is one of the products of SAR response in P. patens. In this study interference RNA (RNAi) was used to decrease gene expression of the allene oxide cyclase (ACe) gene, a key gene in the production pathway of JA. Using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), RNAi was found to significantly lower ACC gene levels in mosses, both before and after infection with the fungal pathogen Pythium irregulare. Furthermore RNAi was tested to see if it created a phenotypic difference when infecting P. patens. Lastly, the preliminary steps in a polyethylene glycol (PEG) mediated transformation were started by attempting to isolate single celled protoplasts in the mosses Mnium cuspidatum and Ceratadon purpureus. This transformation would cause a permanent knockout of a gene, as opposed to the short term decrease in expression achieved by RNAi