Comparative Genomics and Phylogenetic Analysis Revealed the Chloroplast Genome Variation and Interspecific Relationships of Corylus (Betulaceae) Species

作   者：Zhen Yang, Tiantian Zhao*, Qinghua Ma, Lisong Liang, Guixi Wang*
期刊名称：Frontiers in Plant Science
影响因子：3.678
卷 期 号：9
页     码：927
关键词：Corylus, comparative genomics, phylogenetic analysis, chloroplast genome variation, interspecific relationships
论文摘要：
Corylus L. is an economically and phylogenetically important genus in the family
Betulaceae. Taxonomic and phylogenetic relationships of Corylus species have long
been controversial for lack of effective molecular markers. In this study, the complete
chloroplast (cp) genomes of six Corylus species were assembled and characterized
using next-generation sequencing. We compared the genome features, repeat
sequences, sequence divergence, and constructed the phylogenetic relationships of
the six Corylus species. The results indicated that Corylus cp genomes were typical
of the standard double-stranded DNA molecule, ranging from 160,445 base pairs (bp)
(C. ferox var. thibetca) to 161,621 bp (C. yunnanensis) in length. Each genome contained
a pair of inverted repeats (IRs), a large single-copy (LSC) region and a small single-copy
(SSC) region. Each of the six cp genomes possessed 113 unique genes arranged in the
same order, including 80 protein-coding, 29 tRNA, and 4 rRNA genes. C. yunnanensis
contained the highest number of repeat sequences, and the richest SSRs in six cp
genomes were A/T mononucleotides. Comparative analyses of six Corylus cp genomes
revealed four hotspot regions (trnH-psbA, rpoB-trnC, trnF-ndhJ, and rpl32-trnL) that
could be used as potential molecular markers. Phylogenetic analyses of the complete
chloroplast genomes and 80 protein-coding genes exhibited nearly identical topologies
that strongly supported the monophyly of Corylus and simultaneously revealed the
generic relationships among Betulaceae. The availability of these genomes can offer
valuable genetic information for further taxonomy, phylogeny, and species delimitation in
Corylus or even Betulaceae plants.