Triticeae Species Chloroplast Infa-rp136 Regional Genetic Diversity Of The Gene Sequence Analysis

The crops genetic resource has faced a heavy threaten in quantity and diversity with human society expansion, technology development and environment variance. Crop improvement largely depends on genetic resource. Collecting, storing, investigating, innovating and using genetic resource is a basic for the sustained development of people. Genetic diversity among different species comes from their evolution process. Investigations on the plant genetic diversity provided forceful evidence and methods for evolution and speciation.Because people always think much of quality and agriculture properties of the wheat, a self-crossed crop, they put particular emphasis on the properties which fit the target of breeding, such as quality, output, and adaptation, and so on. However, the raising of wheat output and quality based on the intervarietal hybridization was presumably led to the decline of genetic diversity at the same time. To improve the wheat breeding level, it is essential to advance, genetic diversity of basic breeding materials. Studies on genetic diversity between the main basic breeding materials can directly pyramid the target agricultural important properties, increase breeding efficiency, and speed up breeding progress.The cytological (Florescence In-Situ Hybridization) and molecular (Single Nucleotide Polymorphism) markers were used to screen the species and investigate their genetic diversity. Based on the sequenced Triticeae chloroplast genome, a pair of primers in infA-rp136 region was designed and used to amplify DNA from 39 diploid or polyploidy Triticeae species including genera of Secale, Dasypyrum, Elytrigia, Elymus, which have been used widely in distant hybridization and chromosome engineering. The PCR products were cloned, sequenced, and the data were used to cluster analysis. It is expected to supply more thoughts about choosing breeding materials, and guide the Triticeae species genetic diversity researching.The main results are as follows:1. The used Triticeae species were determined to the cytological analysis, and total of 10 diploid, 11 tetraploid and 18 hexaploid material were chosen to the present molecular studies. Fluorescence in situ hybridization (FISH) analysis was further identified to the polyploidy, including accessions of Thinopyrum intermedium. The GISH patterns of Th. intermedium chromosomes indicate fourteen St chromosomes showed strong signals. It is showed that there is a set of St chromosomes in Th. intermedium chromosomes. The genetic studies embodied the diversity and accuracy of the tested material.2. Based on the sequenced Triticeae chloroplast genome, a pair of primers in infA-rp136 region was designed and used to amplify DNA from 39 diploid or polyploidy Triticeae species. The PCR products were cloned and sequenced. DNA sequence analysis revealed that the DNA sequence of coding region of infA gene showed homology as high as 97 percent, and the variation was higher in their intergenic regions than in their coding regions, indicating that the infA gene is highly conserved among species, and it can provides useful information to the research of biological systematics and Genetic diversity.3. Substantial deletions and insertions were found in some deduced amino acid sequences, confirming that infA is one of the most evolutionally active cpDNA genes. Whereas the low variation was observed in rp136 gene, implying that the different genes has different evolutionary speed.4. The constructed phylogenetic trees demonstrate that the polyploidy species Thinopyrum intermedium might have different origin of cytoplasm, and their cytoplasm origins are as complex as their nuclear genome origins. It is speculated that in polyploidization progress, different cytoplasm derived from their individual nuclear chromosome donor, contribute the bigger genetic diversity in cytoplasm of Triticeae polyploidy species. At the same time, genetic diversity in polyploidy species cytoplasm and genetic material transferring between cytoplasm and nucleolus can force differentiation of nuclear gene, and prick up the polyploidy plant species nuclear genome complexity.