Klebsiella oxytoca SYSU-011 isolated from wastewater of a metal-plating plant in southern Taiwan had been proven to be able to degrade cyanide. In this study, we performed proteomic analyses to understand the mechanism of tetracyanonickelate (TCN) resistance in K. oxytoca by using two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and MALDI-TOF-MS techniques. There were 91 protein spots had been induced or overexpressed (≥2 fold) by TCN. Among them, 44 protein spots were successfully identified by MALDI-TOF-MS. The expressed proteins that had been escalated including chaperone, glutathione S-transferase (GST) and alkyl hydroperoxide reductase (AHR) were involved in the TCN detoxification process. Fructose-bisphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglucomutase and 6-phosphogluconolactonase were involved in energy-producing process; nitrogenase and glutamine synthetase (GS) were required to regulate nitrogen assimilation. We also analyzed the K. oxytoca membrane proteins. Twenty six proteins spots had been successfully identified by MALDI-TOF-MS (out of 41 protein) that were induced ≥2 fold by TCN. These proteins induced RND-drive efflux proteins (RND family, MFP subunit, outer membrane factor A and outer membrane factor TolC) and cation efflux system. These efflux pumps could transport nickel ion out of the cells. The induced ATP-binding cassette (ABC) proteins may also play a role in transportation of metal-cyano complexes TCN and nutrition. By this study, we had a better understanding on the defense mechanism of K. oxytoca after exposure to TCN.

The main objective of this thesis dissertation is functionally characterizing the genes involved in biotic and abiotic stresses of plants at molecular level. Previously, upon pathogen attack Rad6 gene expression was found to be changed in wheat and barley plants. To functionally characterize the Rad6 gene, VIGS (Virus induced gene silencing) system was used. HR (Hypersensitive response) like symptoms was detected in every silenced barley and wheat plants. To figure out, transcriptomes and proteomes of Rad6 silenced plants were analyzed. 2-D PAGE analysis was also performed on silenced and control wheat plants. No pathogen growth was observed in Rad6 silenced barley lines. Additionally, the susceptible wild type Arabidopsis plants showed resistant phenotype when any of the Rad6 gene copies is mutated. This suggests that Rad6 gene has a negative regulatory role in plant disease resistance which was proved for the first time. Yeast two hybrid protein interaction study suggests that RAD6 carrying out its function by interacting with SGT1 protein and regulating resistance related genes. It has been first time reported in this thesis that E2 (Ubiquitin conjugating enzyme) takes role in plant disease resistance. Boron which is the other consideration in the scope of thesis as an abiotic stress factor at a very limited amount is necessary for the normal development of plants. This study is conducted on highly boron tolerant Gypsophila perfoliata L. collected from a location in the boron mining area. The plant samples were tested in the presence of high boron (35 mg/kg) concentrations. The transcriptomes of the plant samples treated with the excess levels of boron to that of the samples grown under normal concentration were compared using differential display PCR method. Thirty bands showing differential expression levels at varying time points were analyzed. 18 of them were confirmed via qRT-PCR.