Analysis on Chloroplast Genome Characteristics of the Unique Guizhou Species Acer shihweii
To investigate the structure and characteristics of the chloroplast genome in Acer shihwei,an unique species from Guizhou Province,chloroplast DNA was extracted from fresh leaves of Acer shihwei,followed by genome sequencing and assembly,of which correlation analysis was conducted.The results indicated that the chloroplast genome length of Acer shihwei was 155 069 bp,consisted of a large single copy(LSC)region of 84 840 bp,a small single copy(SSC)region of 18 093 bp,and two inverted repeat regions(IRA,26 068 bp and IRB,26 068 bp).Furthermore,the GC content of the chloroplast genome was determined to be 38%.After annotation,a total of 87 genes were successfully identified,of which they included eight rRNA genes,thirtyseven tRNA genes,and fortytwo protein-coding genes.Through sequence analysis,seventyseven SSR loci were detected with twenty-six loca-ted within dispersed repeat sequences.Positive selection analysis revealed that the rpl16,petD,ycf2,rpl22,and rps16 genes exhibited signals indicative of positive selection.Codon usage bias anal-ysis identified thirtytwo codons with RSCU values greater than one;notably those ending in T pre-dominated with sixteen occurrences.Phylogenetic analysis demonstrated that Acer shihwei was close-ly related to Acer lucidum.