Nontranscribed Spacer Of Nuclear Ribosomal DNA In Oryza Sativa And Their Phylogenetic Implications

The complete internal transcribed spacers (ITS) and Intergenic spacer(IGS) in nuclear ribosomal DNA of ten varieties of Oryza sativa were amplified using PCR technique, cloned, sequenced , and comparatively analyzed including Oryza.officinalis as an outgroup and O. rufipogon as control. The ten varieties were 5 typical varieties of O. sativa ssp. ndica(Minghui63,R288,Guangluai4,Yuichi231-8,Nanjing11),1 variety consanguinity of japonica(indica 9311), 2 typical varieties of O. sativa ssp. Japonica(Nipponbare,Qiuguang), one indica three-line-male-sterile line transferred from male-sterile O. rufipogon(Zhenshan97A), one photo-thermo-sensitive genic male sterile line indica rice breed from the photo-sensitive genic male-sterile lines japonica rice Nongken 58S(Peiai64S).This aim is to probe into the diversity of heredity and consanguinity in Oryza. sativa,which have important theoretics meaning and potential appliance value to discuss the relationship of phylogenetic evolvement of Oryza sativa ,of the heterosis and the genetic background in Hybrid Rice.Main results are showed as follows:1 Characters and phylogenetic analysis of ITS sequences in oryza sativaThe ITS sequences of 10 varieties ranged from 424bp to 426bp in size and G+C content varied from 74.06% to 75.59%, sequences site divergence were 3.75%. Four informative sites, among 12 informative sites which were 2.82% of all sequence sites, in the sequences could be counted as the molecular markers distinguishing between Oryza sativa ssp. indica and Oryza sativa ssp. Japonica,vAnch are C,A,G,A in the 187th,208th,334th,379th position of the alignment in the former.Meanwhile,in the four corresponding sites ,the type of nucleotide of japonica varieties are T,G,A,G.Certain characteristic sites of O.rufipogon or Oryza sativa ssp. japonica were found in the indica male-sterile lines transferred from them.Fourthermore ,it can be found that some colser consanguinity variety,such as Minghu63 and R22, are indentical of ITS sequences.The phylogenetic tree reconstructed on the basis of the complete sequences of ITS in nrDNA by Maximum Likelihood Analysis, showed that Oryza sativa were sorted into two clusters, which indicated two subspecies, i.e, O. sativa ssp. indica and O. sativa ssp. japonica .O.rufipogon locates in the japonica cluster, which means japonica rice is closer to O.rufipogon than indica rice is.2 Characters and phylogenetic analysis of IGS sequences in oryza sativaThe IGS sequences of 6 varieties range from 2133bp to 2152bp in size and G+C content varies from 71.56% to 75.59% which discrepant in different variety, have 210 divergence sites and 49 informative sites which is 9.76%.and 2.28%.by IGS sequences contrast ,we can found that there are 22 molecular markers between typical japonica and indica subspecies and more abundant diversity in subspecies of oryza sativa Because R288 and Minghui63 have 41 sites of divergence while are the same in ITS sequences.The phylogenetic tree reconstructed by Maximum Likelihood Analysis shows that different subspecies , even varieties of subspecies in oryza sativa can be distinguished utilizing IGS sequences.3 Studies on the Relationship between Heterosis and Genetic differentiation in Hybrid Rices parentsstuding the genetic distances of 6 parents varieties of super-hybridrices,Liangyoupei9,Shanyou63,Peiliangyou288,we found that the gentic distances between Peiai64S and 9311 was 0.012,R288 and Peiai64S was 0.009,Zhenshan97A and Minhui63 was 0.009, which means the genetic distances of parents of super hybrid rice Iiangyoupei9 were the farest in these parents studied.This result is correspond with the...