Expressional And Functional Analysis Of DDF1, A Pleiotropic Gene Involving In Vegetative Growth And Reproductive Development In Rice

Rice (Oryza sative L.) is one of the most important food crops in the world, and studies on the reproductive mechanism of rice are very meaningful in both theory and practice. The rice mutants of floral organs are very useful materials to dissect the genes function and their interaction in reproductive growth, especially in floral development. A rice mutant, ddf1(dwarf and deformed flower1) newly found by our research group, possesses the features of significant dwarf in plant height, short and small leaves, significant variability in floral organ with its two lodicules changing into lemma and part or all of the pistils into stamens. Based on the above facts, it was suggested that gene DDF1 is a pleiotropic gene concerning vegetative growth and reproductive growth in rice. In this study, the ddf1 was used as material to dissect the expression characteristics of gene DDF1 and its function. The results are as follows:(1)46 transgenic plants were obtained by constructing GUS expression vector pDDF1and transforming rice callus derived from rice variety Zhonghua 15. Results by GUS staining showed that strong expression signals were detected in the vegetative organs such as roots, leaves and internodes, but no expression signal detected in the apical meristem during vegetative duration. Strong DDF1 expression signals also could be detected in young spike and its branches. In the mature flowers, strong DDF1 expression signals detected in lodicules and pistils, but only weak expression signals detected in the internal and external lemma. Above results indicated that DDF1 is a pleiotropic gene concerning vegetative growth and reproductive growth in rice.(2)46 transgenic plants were gotten by constructing over-expression vector of pTCK303:DDF1 and transforming rice callus derived from rice variety Zhonghua 15. There are no significant differences in their phenotypes between transgenic plants(T0) and their wild type plants. Among 46 transgenic plants, however, 5 plants variously increase in DDF1 expressional levels detected by means of Q-PCR. Since there were no significant differences between the T0 transgenic plants and their wild type plants, their phenotypes including both T1 transgenic plants and their wild type plants, and DDF1 expressions in transgenic plants will be further studied.(3)In order to understand the DDF1expressione locus in cells, by the means of constructing a GFP fusion expression vector of pDDF1:GFP and transforming the onion young epidermal cells through agrobacterium, the results showed that DDF1-GFP fusion protein specially expresses in the nucleus, indicating that DDF1 protein belongs to the nuclear localization protein.