Characterization and comparative analysis of the first mitochondrial genome of <i>Michelia</i> (Magnoliaceae)

Abstract

Genus <i>Michelia</i> has various functions and is valuable in medicine, food, and agriculture. Many plastid genomes (plastomes) of <i>Michelia</i> have been released, but no mitochondrial genomes (mitogenomes) have been reported. In this study, using third-generation HIFI sequencing techniques, <i>Michelia figo</i> (<i>M. figo</i>) mitogenome was <i>de novo</i> assembled into a circular chromosome spanning 773,377 bp with a total GC content of 46.83%. Sixty six genes in total were annotated, including 41 protein-coding genes, 21 tRNA genes, and three rRNA genes. The mitogenome contains 1,514 dispersed repeats (&gt; 30 bp), 39 tandem repeats, and 262 simple sequence repeats. Eighty one fragments originating from the <i>M. figo</i> plastome were detected in its mitogenome and three tRNA genes (<i>trnD-GUC</i>, <i>trnW-CCA</i>, and <i>trnV-GAC</i>) completely transferred from the plastome to the mitogenome. Repeats and collinearity analyses of four Magnoliaceae mitogenomes reveal substantial structural variations, a relatively low degree of collinearity, and significant genetic diversity of this genus. Phylogenetic analysis showed that two phylogenetic trees constructed separately based on mitogenomes and plastomes accurately depict the phylogenetic relationship of <i>M</i>. <i>figo</i>. This study offers the first comprehensive comparative genomic and phylogenetic analysis of the <i>M</i>. <i>figo</i> mitogenome, facilitating the development of genetic markers, taxonomic classification, and resource exploration within the <i>Michelia</i> genus.

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