All aspects of plant life are controlled by the regulated synthesis of new proteins and the precise degradation of preexisting proteins, predicting up to 50% of total plants protein is replaced every week. The ubiquitin/26S proteosome pathway is known to be one of mechanisms to regulate signal pathways, developmental process and abiotic/biotic stress responses via protein degradations. In the previous study, we have identified a large number of the RING ubiquitin ligase proteins whose functions have been clarified in the protein degradation pathway. Curiously, one RING-H2 finger protein gene evidenced striking differences in expression patterns in response to salt and dehydration stress between leaf and culm-node tissues. Characterization of the gene evidenced its function as E3 ubiquitin ligase activity by using an in vitro ubiquitination assay. We have constructed a library with rice culm-node tissues under salt stress for Yeast two hybrid assay and performed primary yeast two-hybrid screening with the gene as a bait. A total of 13 candidate genes were isolated as positive interacting partners. Gene ontology of most candidate genes appears to be related with various abiotic stresses. Therefore, the RING-H2 finger protein genes might function to regulate plant abiotic stress responses via protein degradation pathways.

• Sung Don Lim(Plant Genomics Lab, Dep. of Applied Plant Sciences, Kangwon National University)
• Ju Kyong Lee(Plant genetic & Breeding Lab, Dep. of Applied Plant Sciences, Kangwon National University)
• Cheol Seong Jang(Plant Genomics Lab, Dep. of Applied Plant Sciences, Kangwon National University) Corresponding author