Phylogenetic Analysis of Oryza officinalis Complex Based on Ribosome ITS1 and ITS2 Sequences

Five wild rice species in the O.officinalis complex and two cultivated rice varieties were phylogenetic analyzed based on the ribosome ITS1 and ITS2 sequences.Their complete ITS and the 5.8S sequences on the ribosome region were amplified by polymerase chain reaction technique and were analyzed by online software CLUSTAL W(2.0.12)Multiple Sequence Alignments and Neighbor Joining.The results showed the ITS sequences all had high G/C contents.By comparison,the ITS1 had relatively high sequence length polymorphism and the ITS2 had more base mutations.O.officinalis and O.alta were clustered together in the phylogenetic tree and they were far from the cultivated rice species.The O.australiensis,O.punctata and O.brachyantha were located between these two clusters and they were on the interim phase of rice evolution.