青花菜线粒体基因组组装与序列特征分析

为更好地从分子水平了解青花菜，对青花菜进行线粒体基因组组装，并对其序列特征进行分析。青花菜线粒体基因组大小为219 964 bp，GC含量为45.25%。线粒体基因组注释到61个基因，包括33个编码蛋白基因，23个tRNA基因，3个rRNA基因和2个假基因。其中8个基因的核苷酸多样性较高；24个基因无核酸多样性。变异数量最多的基因是 rrn26、 rrn18和 atp1，其变异数量分别为326、277和136。密码子偏好性分析结果显示RSCU值>1的密码子有29个，大多以A/U碱基结尾，表明其密码子更偏向于A/U结尾。基因组序列中共检测到345个重复序列，包括170个正向重复序列和175个回文重复序列。青花菜与花椰菜的线粒体基因组具有极好的共线性，且基因的位置基本一致。青花菜线粒体和叶绿体基因组中共检测到22条同源片段。同源片段总长度为13 355 bp，平均607 bp。

Mitochondrial Genome Assembly and Sequence Characterization in Broccoli

In order to better understand it at the molecular level,the mitochondrial genome of broccoli was assembled,and its sequence characteristics were also analyzed in this study. The mitochondrial genome was 219 964 bp,with a GC content of 45.25% in broccoli. 61 genes were annotated,including 33 protein-coding genes,23 tRNA genes,3 rRNA genes,and 2 pseudo genes. Among these genes,eight genes had high nucleotide diversity,while 24 genes had no nucleic acid diversity. The genes rrn26, rrn18 and atp1 had the most variants,with the number of variants being 326,277 and 136,respectively. The codon preference analysis showed that there were 29 codons with RSCU>1,most of them ending with A/U base,indicating that the codon usage tended towards more frequently ending in A/U base. A total of 345 repeats were detected in mitochondrial genome,including 170 forward repeats and 175 palindromic repeats. The mitochondrial genomes of broccoli and cauliflower exhibited excellent collinearity,and the sequence of genes was basically the same.The gene location was also consistent. A total of 22 homologous fragments were detected in the mitochondrial and chloroplast genome in broccoli. The total length of these homologous fragments was 13 355 bp,with an average of 607 bp.