Study Of The Mitochondrial Genome Of A Glycine Max Landrace

As one species of the legume, Glycine max is rich of protein and fatty acid. Gmax is one important source of food and has extensive value of industrial application. This study sequence the mitochondrial genome of a soybean accession----Aiganhuang (N21249), analyzed the gene content of the genome, compare the gene transfers between mitochondrial genome, chloroplast genome and nuclear assembly of the soybean, horizontal transfer is also discussed. Additionally, we analyze the evolution of the mitochondrial genome of seed plants. Main results are as follows:1. The mitochondrial genome:Sequencing the mitochondrial genome of G. max has produced an complete molecule402,558bp in length,58genes (73,389bp in total length) were identified, including36protein-coding genes, three rRNA genes (5S,18S and26S rRNAs) and19tRNA genes, these genes with known function account for18.2%of the whole genome. Additionally, soybean mitochondrial genome has been predicted to have54ORFs with unknown function. There are many repeats in the genome, the size of short repeats is less than1kb, and is mainly of less than500bp.The short repeats account for4.2%of the soybean mitochondrial genome, are detected to be uniformly distributed in the genome. Tandem repeats are also identified in the genome, but only4tandem repeats with size ranging from12bp to18bp have been discovered. Large repeats summed to be59,273bp, accounting for14.7%of the genome. All of the repeats are summed to be76.4kb, accounting for19.0%of the soybean mitochondrial genome.2. Rearrangement of the mitochondrial genome:We searched the soybean mitochondrial genome against an available soybean nuclear assembly, total matches are1907, and these hits cover270kb of the mitochondrial genome,450kb of the nuclear genome. The mitochondrial genome sequence was searched against the soybean chloroplast genome, hits obtained cover3.9kb (2.5%) of the chloroplast genome, and cover the4.4kb (1.1%) of the mitochondrial genome. Some sequences are shared by the three soybean genomes nucleus, mitochondria and chloroplast, these are summed to6.0kb. Two horizontal transfers from bacterial genome have been found in the soybean genome, of which one is a106bp segment homologous to Staphylococcus simiae CCM7213, another is a segment of128bp homologous to bacterial DNA.This study has elucidated the structure of the soybean mitochondrial genome and gene transfers between the soybean mitochondrial genome and other genomes. All these results lay hard foundation for studing the evolution of mitochondrial genome of seed plants.