马蹄参叶绿体基因组结构及SSR特征分析OA

In order to clarify the structural evolution rules of the chloroplast genome of this rare forest tree and develop molecular markers for forest germplasm identification and population genetic evaluation,high-throughput sequencing technology was adopted in this study to assemble,annotate and conduct comparative analysis on chloroplast genomes from 14 natural populations covering the entire distribution range of Diplopanax stachyanthus.The results showed that the chloroplast genome of D.stachyanthus had a typical quadripartite structure,consisting of a large single-copy(LSC)region,a small single-copy(SSC)region,and a pair of inverted repeats(IRa and IRb).The genome length ranged from 158 509 bp to 159 027 bp,and the overall GC content was 37.7％-37.8％,with significantly higher GC content in the IR regions than in the LSC and SSC regions.Codon usage analysis indicates that most preferred codons end with A or U.We detected 46-51 SSR loci across the genomes,mostly A/T mononucleotide repeats.The number and types of SSRs were highly conserved among populations,with only minor variation.IR boundary comparisons revealed largely consistent gene arrangements across samples,except for small differences in the boundary-spanning lengths of a few genes,such as rps19 and ndhF.The SSR loci identified in this study exhibited high polymorphism and stability.