Cytokinin Response Factor 4: A Role in Development During Cold Stress in Arabidopsis thaliana

Abstract

Cold stress is a major cause of crop loss annually in the United States such that a detailed study of the mechanisms and genes behind these stresses are essential for improvement of crop plants. This thesis investigated the role of Cytokinin Response Factor 4 (CRF4) in cold stress response. Transcript levels of CRFs at different developmental stages and times after cold treatment revealed that CRF4 is activated by the cold stress response pathway in the accumulation phase and possibly during freezing stress response. Examinations of plants under both cold and high sucrose revealed that CRF4 appears to be important in promoting germination, negatively regulates shoot development, and high CRF4 levels can repress root growth. It also appears that CRF4 has different mechanisms of response to cold stress in shoots and roots, which can be seen in timing of expression response that shifts as development progresses.