Classification And Origin Analysis Of Weedy Rice

Weedy rice （Oryza sativa L.） is a middle type of rice with both wild rice and cultivatedrice characteristics which has suffering long-term natural selection and human intervention.Because of the bad growing conditions, it has many excellent resistance characteristics （canresist about drought, cold, pest, salinity, etc.） and it is a genetic treasure of rice molecularbreeding. Chloroplast molecular marker is a common molecular biological method aboutweedy rice analysis. It has many advantages, such as fast, accurate, informative. We use theORF100, ORF29-TrnC^GCAindica-japonica specification markers to classify the weedy riceand sequencing psbA-trnH gene spacer fragments about the weedy rice, in order to find anyevidence about the origin of weedy rice.Most of the traditional analysis of chloroplasts requires the complete chloroplast DNAextracted from plant leaves or requires large amounts of plant DNA as a template. This is acomplex and time-consuming extraction process. Because of the high specificity of PCRreaction, this study uses the CTAB and SDS methods to extract total DNA from varioustissues of the weedy rice. Then select the five pares chloroplast primers in PCR reaction. Theamplification result shows the leave templates consist with the root and seed templates whichdoes not conflict with the other studies. This conclusion may simplify the experimentalprocess and accelerate the speed of analysis.In order to improve the speed and accuracy of the weedy rice’s indica-japonicaclassification, this study uses the primers about ORF100and ORF29-TrnC^GCAindica-japonicaspecification markers to establish a multiple PCR reactions. The results clearly distinguishseveral indica and japonica differentiation about weedy rice. In the40weedy rice samples,indica rice is15and japonica rice is25, Japonica rice is majority.Fragment of the chloroplast psbA-trnH gene spacer region is a good response to weedyrice species evolution and species diversity, through the analysis of this sequence at themolecular level may find some evidence about the origin of weedy rice. In this experiment,several psbA-trnH fragments of weedy rice are cloned and sequenced, and search the genesequencing results in the DNA database. Use the molecular genetic data analysis software to establish the NJ and ME phylogenetic trees. The intuitive graphical data shows the ricesamples are separate into two branches including indica and japonica. Weedy rice samples aremore close to indica branch in evolutionary. These visual graphics data can provide someevidence about the weedy rice origin in molecular level.