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转座子和逆转座子的大量插入,是高等植物基因组进化的重要动力。作为植物基因组研究热点的禾本科植物之一,毛竹基因组大小约为2 Gb,60%为重复序列,长末端重复序列型逆转座子(LTR逆转座子)则占全部重复序列的一半以上,然而目前对毛竹基因组中LTR逆转座子及进化情况知之甚少。本研究利用已发表的毛竹基因组序列,首次通过大数据筛查预测获得9 436个平均长度10.3 kb的全长LTR逆转座子。通过分析,我们估算出毛竹LTR逆转座子插入基因组的时间主要分布于200~500万年前,晚于毛竹基因组四倍化的时间。研究还发现了29个位于全长LTR逆转座子内部、有转录组序列支持的蛋白编码基因,这些毛竹基因均不符合所在基因组区段的毛竹-水稻基因共线性关系,且位于LTR逆转座子内部的基因与存在于染色体其他位置的同源基因在表达模式上有着较大差异。本研究首次尝试从LTR逆转座子的角度探索毛竹基因的进化历程,也为今后的植物基因组研究提供了重要的基础数据。
The massive insertion of transposons and retrotransposons is an important motivation for the evolution of higher plant genomes. As one of the gramineous plants in plant genomics research, the genome of Phyllostachys pubescens is about 2 Gb in size and 60% is a repetitive sequence. The long-terminal repeat-type retrotransposon (LTR retrotransposon) accounts for more than half of the total repeats, however, Little is known about the LTR retrotransposons and evolution in the genome of the bamboo. In this study, 9 436 full-length LTR retrotransposons with an average length of 10.3 kb were predicted by big data screening using the published sequence of moso bamboo genome. Through the analysis, we estimated that the time for insertion of LTR retrotransposons into the genome of M. moschata mainly ranges from 200-500 million years ago, which is later than that of Phyllostachys pubescens genome. The study also found 29 coding genes located within the full-length LTR retrotransposons and supported by transcriptome sequences. All of these genes did not fit with the symbiotic relationship of the Phyllostachys pubescens-rice genes in the genomic locus and located in the LTR retrotransposons Internal genes and exist in other positions of the chromosome homologous genes in the expression patterns are quite different. This study, for the first time, explored the evolutionary history of Phyllostachys pubescens from the perspective of LTR retrotransposons and provided important basic data for future plant genome research.