Cloning And Sequence Analysis Of Actin Genes From Torenia Fournieri L.

Torenia fournieri L. is an important flower plant that grows in semi-tropics and tropics, with special and naked megaspore, and it is also a model plant which can be used to study the development of flower apparatus and the progress of impregnation. In this study, two actin genes were isolated for the first time from fournieri, by using polymerase chain reaction (PCR) technique. Characterization and functional prediction of the two novel genes were performed. The results of isolation and analysis of the genes are very helpful to elucidate their molecular evolution, functional expression in the development of flower apparatus, progress of impregnation and potential application in artificial intervention and blocking of the embryo development. The major experimental results from this work were as follows:Three methods, low pH extraction medium with high salts precipitation, SDS precipitation and CTAB precipitation, were used to extract genomic DNA from the leaves of fournieri. The DNA samples from the three methods were tested using UV scanning, agarose gel electrophoresis and PCR. The differences in yield and quality of the obtained DNA samples were compared, and CTAB precipitation was determined to be the best method for the practical work..We designed and synthesized two pairs of primers according to nucleotide sequences of Striga asiatica actin genes of and other higher plants. By using the total DNA of fournieri as template, 1383bp and 1355bp fragments were amplified using PCR. The sequence analysis of the two fragments demonstrated that the nucleotide sequences belonged to the actin gene family of fournieri. It was proved by blasting GenBank database that the two sequences were novel sequences which were called "TF-ACT1" and "TF-ACT2" respectively.Alignment of cloned fragments revealed that TF-ACT1 and TF-ACT2 shared homologywith the known actin genes from other plants, such as Nicotiana tabacum, Striga asiatica, Solarium tuberosum, Arabidopsis thaliana. The deduced amino acid sequences of TF-ACTl and TF-ACT2 shared more than 90% identity with those of other plants.