| Based on two molecular markers SRAP (sequence related amplified polymorphism) and rDNA-ITS (ribosomal DNA internal transcribed spacer),population genetic structure and diversities, sequence (ITS1-5.8S-ITS2) as well as ITS2 secondary structure etc of A. beshanzuensis were conducted and the results were as follows:1. SRAP analysis of genetic diversities from A. beshanzuensis11 and 9 pairs of SRAP primers were used to analysis the relationship among A. beshanzuensis populations and within species of plant samples,the polymorphism percentage of which is high, but the level of genetic diversity is very low. All samples showed low genetic diversity in this study,the relationship between the level of genetic diversity is as follows: A.yuanbaoshanensis>A.chensiensis>A. beshanzuensis > A. fanjingshanensis >A.firma.(1) The analysis conclusion among different Abies populations :According to Nei' S genetic diversity index, Ht=0.1426, the genetic diversity about 30 samples of A. beshanzuensis, Hs=0.1123, it shows that the genetic diversity of Abies in different populations is very low. The genetic diversity of among different source of gene, Gst (differentiation degree)=0.2105. It illustrated that the differentiation between populations was very high. Gene flow among provenances was Nm=1.9505, which is far greater than 1. The gene flow is a movement between and within populations genes, indicating the certain flow among genes of fir.UPGMA clustering analysis showed that A. fanjingshanensis has the closest relationship with A. beshanzuensis, then follow A. firma and A.chensiensis, while A. yuanbaoshanensis has the most distant relationship.(2) The analysis conclusion among A. beshanzuensis intraspecific populations: Native trees and most moved to protect the mountain, grafting.There was a significant distance between the samples of the original and the protected, the grated, which indicated that there is obvious variation in the fir samples gene of artificial cultivation and grafting, which provided favorable factors for the survival of the Abies.2. Analysis on sequence of ITS1-5.8S-ITS2 and ITS2 structure from A. beshanzuensisThe results disclosed that, the length of the complete ITS1-5.8S-ITS2 from A.beshanzuensis ranged from 1376 to 1720bp, and the length variance mainly occurred in ITS1 region (1006-1350bp) while the length of 5.8S(162bp) and ITS2 (208bp, only one or two samples with 207/209bp) were highly conservative. The homologous identities of 5.8S and ITS2 were over 97% and 98%, respectively. The average percentage of GC content of ITS2,ITS1 and 5.8S decreased gradually (over 60%, immediately close to 60%,about 51.23%, respectively). ITS sequence variance (such as indels and nucleotide substitutions), mainly appeared in ITS1 region, and the deletion of long fragment of DNA occasionally occurred in several samples (or clones). The ITS2 could form classic conservative structure with 4 helix arms (?/?/?/?) and 1 central loop as well as U-U mismatch and UGGU motifs, which implied that ITS2 structure may function as the reference for molecular phylogenetic analysis. The phylogenetic tree revealed that, 3 ancient trees and natively-grown seeding from A.beshanzuensis, shared relatively close genetic relationships with one another,as well as A.chensiensis and A.ziyuanensis, respectively,and high divergence with Abies from European and American countries.This study provided basic information on deep exploitation of genetic structure, population diversities and phylogenetic relationship of A.beshanzuensis, and the available data would play important roles in population protection, classification and identification, as well as artificial breeding of A.beshanzuensis. |
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