Molecular Biology Of The Wild Genetic Resources In Hordeum L.Native To China

The genus Hordeum L. belongs to the tribe Triticeae of the family Poaceae (Gramineae). It comprises about 45 species and subspecies distributed across the temperate zones of both the Northern and the Southern hemispheres. China is one of the centers of diversity for Hordeum. The objectives of this paper were to evaluated the genetic diversity and the genetic relationships among H.bogdanii native to Xinjiang, to construct the phylogenic relationships among the species or subspecies in Hordeum native to China by using RAPD, STS-PCR and ISSR markers, and to sequence the ITS region of nrDNA and the psbL-psbJ of cpDNA. The main results are as the shown following:1. The genetic diversity among 32 H. bogdanii Wilensky accessions native to Xinjiang, China was investigated by RAPD markers. Of the 40 arbitrary 10-mer primers used for PCR amplification, the amplified products of 22 primers (55.0%) showed polymorphism. The results showed that all 32 accessions could be distinguished by RAPD markers. It-also suggested that the genetic diversity of H. bogdanii based on RAPD markers was closely correlated with geographic distribution.2. The genetic diversity among 32 accessions of H. bogdanii Wilensky native to Xinjiang. China was evaluated by 22 STS-PCR primer sets derived from RFLP clones of the wheat (Triticum aestivum L.) or barely (H. vulgare L.) mapping. Of the 22 STS-PCR markers, while 19 out of 22 markers (86.4%) and 46 out of 88 marker/enzyme combinations (52.3%) revealed polymorphisms. Based on the GD matrix, a dendrogram showing the genetic relationships between accessions was constructed using the UPGMA method. The results showed that all 32 accessionscould be distinguished by STS-PCR markers. The result indicated that the genetic diversity of H. bogdanii based on STS-PCR markers is closely correlated with geographical distribution.3. Using 35 ISSR primers, the genetic diversity among 32 accessions of H. bogdanii Wilensky native to Xinjiang, China was investigated. Of the 35 ISSR primers, 9 primers could generate distinct amplified products. The results showed that all 32 accessions could be distinguished by ISSR markers. It also indicated that the genetic diversity of H. bogdanii based on ISSR markers is closely correlated with geographical distribution.4. It indicated that RAPD markers produced more information than STS-PCR markers, while the extend of band polymorphism of ISSR markers was greater than that of RAPD markers by comparison of genetic diversity matrixes based on different markers.5. The genetic diversity among 32 accessions of H. bogdanii Wilensky native to Xinjiang, China was detected by using 7 cpDNA STS-PCR markers. The results showed that all 32 accessions could not be distinguished by 7 cpDNA STS-PCR markers.6. By using 7 mtDNA STS-PCR markers, the genetic diversity among 32 accessions of H. bogdanii Wilensky native to Xinjiang, China was investigated. The results showed that all 32 accessions could not be distinguished by 7 mtDNA STS-PCR markers.7. It indicated the cpDNA and mtDNA genomes are highly conserved in H.bogdanii, and the extend of the genetic variations is very limited. The level of genetic diversity of cpDNA among H.bogdanii was equal to that of mtDNA.8. The internal transcribed spacer (ITS) of nuclear ribosomal DNA (nrDNA) of 8 and 7 species or subspecies of Hordeum from China and other countries, respectively, were investigated by PCR amplification and direct sequencing. The length of the entire ITS region of the Hordeum species or subspecies varied from 596 to 600bp.The numbers of variable sites were 43, 4 and 54 in ITS1. 5.8S and ITS2, respectively. The ITS sequence divergence were low, ranging from 0 to 0.1121 with the mean of 0.0561. Using Bromus tectorrum L. as outgroup, phylogenetic relationships among 13 species or subspecies in Hordeum were estimated by neighbor-jioning method. It indicated phylogenetic relationships in Hordeum were not closely related with its geographical distri...