Chinese pine (Pinus tabuliformis Carr.)
Chinese pine (Pinus tabuliformis Carr.)
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油松 (Pinus tabuliformis Carr.)
DOI：
10.1016/j.tig.2022.01.006
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发表时间：
2022
影响因子：
11.4
通讯作者：
Yue Li
中科院分区：
文献类型：
--
作者：
Shihui Niu;Wei Li;Yue Li
油松，俗称油松，是一种耐旱、耐寒、喜阳的乡土针叶树种，广泛分布于中国。它有一个巨大的基因组，包括25.4 Gb，有12个巨大的染色体。最近公布的近完整的油松基因组为研究针叶树的基因组扩展和适应性进化提供了新的视角。随着基因组的扩增，在油松基因组中观察到大量的长内含子。有趣的是，具有超长内含子的大基因往往以更高的水平表达，这表明内含子长度可能是裸子植物进化的动力，尽管其潜在的分子机制仍然未知。这些显著扩展的基因家族主要与生物和非生物胁迫反应有关，这可能是适应成功的分子基础，使针叶树成为广泛分布和迄今为止数量最多的树种组存在的今天。关于基因组的有趣事实25.4-Gb的油松巨型基因组主要归因于巨大的基因间区域（93.2%），重复率高（69.4%）。转座子的连续积累和缓慢的、不平等的重组介导的旧重复序列的去除可能有助于“单程票”基因组扩增。随着基因组的扩增，大量超长基因是由转座因子在内含子中的插入和共存而产生的。引人注目的是，非常长的内含子对基因转录没有任何不利影响;相反，较大的基因已经进化到具有更高的表达水平。
Pinus tabuliformis, commonly called Chinese pine, is a drought-and cold-tolerant heliophilous, indigenous conifer species, widespread in China. It has a giant genome comprising 25.4 Gb, with 12 huge chromosomes. The recently released nearly complete genome of P. tabuliformis provides new perspectives on genome expansion and adaptative and reproductive evolution of conifers. With an expansion of the genome, a multitude of long introns were observed in the P. tabuliformis genome. Interestingly, large genes with ultra-long introns tend to be expressed at higher levels, which suggests that intron length may serve as an evolutionary force in gymnosperms, though the underlying molecular mechanism is still unknown. The significantly expanding gene families are mainly associated with biotic and abiotic stress response, which probably serves as the molecular basis of adaptation success, enabling the conifer trees to become widely distributed and by far the most numerous groups of tree species that exist today.Fun fact about the genome The 25.4-Gb P. tabuliformis giant genome is mostly attributable to huge intergenic regions (93.2%) with high repeat content (69.4%). A continuous accumulation of transposons and slow, unequal recombination-mediated removal of old repeats may contribute to a ‘one-way ticket’genomic expansion. With the genome expansion, a lot of ultralong genes were derived by the insertion and coexistence of transposable elements in introns. Strikingly, extraordinarily long introns did not show any detrimental effects for gene transcription; on the contrary, the larger genes have evolved to have a higher expression level.