The Molecular Systematics and Classification of Triticeae Polyploids with St Genome
|School||Henan Agricultural University|
|Keywords||Triticeae St Genome ITS sequence hybridization- differentiation phylogeny polyploidy|
Plant species constituted with St genome contains more than half of Triticeae species, a large number of disease resistance and stress resistance genes in wheat breeding, and provides good genetic resources for improvement and breeding of the wheat crop and forage quality.In carries on the plant member systematic research process, the choice of suitable evolution speed of the gene or the DNA fragment is very important regarding the system growth relations inference. Because plant nrDNA ITS in the cell nucleus evolves the speed very quick, may provide the richer information bit spot. At present it has been widely applied to the research angiosperm, inter-species and so on. The domestic and foreign scholars have more differences in the Plant species constituted with St genome phylogenetic, therefore, there has the necessary to carry on the discussion.The research take the nrDNA ITS sequence as the object, to mensurate ITS complete sequences of the 17 species 36 kind of Pseudoroegneria, Elymus , Elytrigia, Hordeum plant and an outgroup Bromus cartharticus which using system growth analysis software to carry on the analysis.Obtained result as follow:1. The nrDNA ITS sequences of the 31 plant species constituted with St genome were obtained by primer designing, PCR, cloning and sequencing, which subsequently were used to analyze the phylogenetic relationships in the genus by homologous blast and clade analysis.2. In the data of 36 plant including the ITS sequences downloaded from GenBank, the percentage of phylogenetically informative sites is 13.2%. According to the above statistics, there are relatively abundant informative sites in the ITS sequences of plant species constituted with St genome.3. According to the source of diploid genome in plant species constituted with St genome, based on the ITS sequence data genealogical tree has three clades(H, Ee and St). (1) In the H clade, 5-Elymus.glaucus and diploid plant with H genome gather in one clade, indicate that 5-Elymus.glaucus contain ITS of H genome, which support cytology data results of StH genome in molecular level. But, 25-Elymus burchan-buddae and diploid plant with H genome gather in one clade, indicate that 25-Elymus burchan-buddae also contain ITS of H genome. And 25-Elymus burchan-buddae experienced introgreessive events come from individual plant with H genome. (2) Ee clade also support that 9-Elytrigia.intermedia has Ee genome in the molechlar data. (3) St clade is the biggest one in the three clades, almost include all the plants in the study, indicated that the plants have St genome.4. St clade of genealogical tree can be divided into two sub-clade, one is based on Elymus.cylindricus, another is based on Elymus.tangutorum, which indicate that genonomy of two species are very close and the species is the origin of independence. But no other species have obvious genonomy, indicate that the species are multiple origins or experienced repeatedly hybrid and introgressive events.5. The research choose three clones and sequencing. The results of genealogical tree indicate that the research almost acquire the ITS sequence of St genome. And the study also get ITS sequence of Ee and H genome ,which lay a solid foundation for for follow-up work.