Introduction Of CyclAt Etc Into Rice By Particle Bombardment And The Analyses Of Gene Recombination In T₁ Transgenic Rice

Genetic improvement of rice by introducing exogenous genes is considered an effective method of rice breeding (named molecular breeding), which can improve rice's insect resistance, pathogen resistance and drought resistance and some have substantially succeeded. In the research of this paper, we transduced several exogenous genes, cyclAt and IPTetc, into rice via particle bombardment. The ectopic expression of these exogenous genes in rice should help us to understand the regulation mechanism of rice endosperm during early development and might improve the development of rice grain on molecular level.1 Study on introducing cyclAt into Rice by Particle BombardmentHere, target gene cyclAt, choice gene HPT and report gene GUS were co-transformed into the embryonic calli originated from mature rice seeds via particle bombardment, transgenic rice plants have been obtained. The X-Gluc staining analysis showed that report gene GUS expresses with high efficiency in both calli and leaves of the regenerated plants. However, using genome DNA of the transgenic plant leaves as template, and primers specific to full sequence of cyclAt to amplify this exo-gene by PCR, only a fragment of 1 000 bp was obtained, smaller than the full sequence of 1 604 bp, so we conjectured that cyclAt might change the self-configuration or has been montaged as recombinating with the genome of the acceptor rice. In addition, there exist limitations by using GUSas report gene to evaluate cyclAt transformation, for the two genes might integrate randomly with genome DNA of the acceptor, althoughthe frequency of both of them integrated simultaneously was indeed much higher than that of one single gene integration. Moreover, Southern blot detection showed that 15 plants of transgenic rice were negative for cyclAt.2 The analyses of IPTgene recombination with acceptor genome and its influence on biological and Agricultural characters of Ti transgenic riceAccording to the 697 bp~1353 bp sequence of IPT gene, we designed specific primers, then did PCR to amplify the about 650 bp anticipated fragment by using genome DNA from the leaves of 7 Ti transgenic rice stains as template, sequence analysis identified that the exact fragment was obtainedo Meanwhile, Southern blot detection also showed that the exo-gene had been introducted into the receptor. Comparison to the control plants (non-transgenic rice), the Tt transgenic rice expressed obvious difference in biological and agronomic characteristics, especially to kernel weight, which raised about 16.0%.