Chloroplast Genome And Phylogeny Of Opisthopappus

As an endemic species in China,Opisthopappus Shih is listed as the second group of endangered plants,mainly distributed in the Taihang mountains.It temporary includes Opisthopappus taihangensis(Ling Shih)and Opisthopappus longilobus Shih.The chloroplast genome sequence of Opisthopappus genus was obtained by high-throughput sequencing,then functional gene annotation analysis and comparative genomics analysis were carried out,that would reveal the classification and phylogenetic status and provide a theoretical basis for the utilization and genetic diversity protection of the Opisthopappus genus.In the chloroplast genome,42.4%(64100bp)of the sequence was gene coding regions,a total of 85 genes were encoded that including 38 t RNA genes,4 r RNA genes(in reverse repeat each have two copies),28 protein-coding genes,and the average length was 754 bp.Non-gene coding regions accounted for 57.6% of the entire chloroplast,including intergenic regions(the GC content is 36.7%)with 87069 bp in length.The total length of cp DNA genomes of O.taihangensis was 151169 bp,while that of O.longilobus was 151403 bp.The percentage of GC content was also 38.3% in the two species.There were 391 SNPS and 118 Indels in the two chloroplast sequences.Collinearity analysis showed that the anchored markers on the genetic maps of the two species was consistent and the genetic distance was close.The d N/d S ratio was less than 1,which indicating that the selection pressure of chloroplast protein-coding genes was negative selection in two species.Based on the gene functional annotation,142 unigenes involved in fatty acid metabolism,purine metabolism and biosynthesis of tetracycline were annotated into 19 KEGG pathways.Among GO annotations(including Biological process,Molecular function and Cellular component),Biological process in the cell and metabolism process had the largest percentage(100%),followed by biological signals and biological and positioning.The number of proteins involved in binding and catalytic functions accounted for more than 80% of the total.The number of organelles,cellular parts and cellular proteins in the cellular components is100 %.COG functional analysis showed that the chloroplast genome proteins were divided into six functional groups:(1)energy products and conversion;(2)translation;(3)ribosome structure and biogenesis;(4)transcription;(5)modification and repair of after translation;(6)transport and metabolism of carbohydrate and lipid.Within the phylogenetic tree,the two species under Opisthopappus gathered into one branch,Chrysanthemum morifolium Ramat,Dendranthema chanetii(Lévl.)Shih and Pedicularis monbeigiana Bonati gathered one branch.Opisthopappus should be more evolution than other species.