Abiotic Stress Tolerance Evaluation Of A Maize Transcription Factor ZmCBF3 In Transgenic Rice (Oryza Sativa)

The output of major crops, such as rice and corn, is severely affected by drought, high salinity, cold and other abiotic stresses. So, breeding the novel of rice as cold,drought and salt resistance is significant. A CBF (C-repeat binding transcription factor) CBF3 gene from maize has been cloned in preliminary work, named ZmCBF3. The overexpression vector Ubi::ZmCBF3 has been constructed, and has been transformed into rice and a number of T0 overexpression rice lines have been obtained. The T1 generation of transgenic rice overexpressing ZmCBF3 has been screened and identified, 3 homozygous lines have been obtained. The phenotype and physiological changes of this three independent T3 transgenic homozygous lines have been investigated under the drought, high salt and cold stress conditions. The affect of ABA on the seed germination of transgenic seeds and wild-type seeds was observerd, and the possible relationship between regulatory pathways of ZmCBF3 and ABA has been analyzed. In order to assess the feasibility of drought resistance of the transgenic rice in the field, the grain yield of homozygous transgenic rice lines and wild-type rice in the field under both normal conditions and drought stress were compared. In order to lay the foundation for clarifying the physiological functions and molecular mechanism of ZmCBF3 gene in transgenic rice under drought cold and salt stress, the relationship between the ZmCBF3 gene and three genes associated with stress response has been investigated finally.The main results of this study are as follows:1. Three transgenic homozygous lines have been identified from 89 transgenic plants. These transgenic homozygous lines have been named 0X-209-1, 0X-209-2 and 0X-209-3.2. Homozygous transgenic rice lines 0X-209-1, 0X-209-2, 0X-209-3 and wild-type rice have been treated under drought, high salt and cold stress, and the survival rate, MDA content and relative electrical conductivity and other physiological indexes have been analysised. The Results show that ZmCBF3 gene can enhance abiotic stress tolerance of plants.3. Transgenic rice may be ABA sensitive.4. Grain yields between homozygous transgenic rice lines and wild-type rice in the field under normal conditions show no differences. But under drought stress, the transgenic rice lines 0X-209-2 shows more grain yields than the wild type.5. ZmCBF3 can induce the upregulation of stress response genes such as Dip1, Hsp70 and Lip5.