USDA-ARS-MWA, Plant Genetics Research Unit, University of Missouri, 205 Curtis Hall, Columbia, MO 65211, USA.
BMC Genomics. 2010 Feb 27;11:143. doi: 10.1186/1471-2164-11-143.
Tortula ruralis, a widely distributed species in the moss family Pottiaceae, is increasingly used as a model organism for the study of desiccation tolerance and mechanisms of cellular repair. In this paper, we present the chloroplast genome sequence of T. ruralis, only the second published chloroplast genome for a moss, and the first for a vegetatively desiccation-tolerant plant.
The Tortula chloroplast genome is approximately 123,500 bp, and differs in a number of ways from that of Physcomitrella patens, the first published moss chloroplast genome. For example, Tortula lacks the approximately 71 kb inversion found in the large single copy region of the Physcomitrella genome and other members of the Funariales. Also, the Tortula chloroplast genome lacks petN, a gene found in all known land plant plastid genomes. In addition, an unusual case of nucleotide polymorphism was discovered.
Although the chloroplast genome of Tortula ruralis differs from that of the only other sequenced moss, Physcomitrella patens, we have yet to determine the biological significance of the differences. The polymorphisms we have uncovered in the sequencing of the genome offer a rare possibility (for mosses) of the generation of DNA markers for fine-level phylogenetic studies, or to investigate individual variation within populations.
Tortula ruralis 是 Pottiaceae 藓科中分布广泛的物种，越来越多地被用作研究干燥耐受性和细胞修复机制的模式生物。在本文中，我们介绍了 T. ruralis 的叶绿体基因组序列，这是第二个发表的藓类植物叶绿体基因组，也是第一个营养体干燥耐受性植物的叶绿体基因组。
Tortula 的叶绿体基因组约为 123500bp，与第一个发表的藓类植物 Physcomitrella patens 的叶绿体基因组在许多方面存在差异。例如，Tortula 缺乏 Physcomitrella 基因组大单拷贝区中约 71kb 的倒位，以及 Funariales 中的其他成员。此外，Tortula 叶绿体基因组缺失了 petN 基因，该基因存在于所有已知的陆地植物质体基因组中。此外，还发现了一个不寻常的核苷酸多态性案例。
尽管 Tortula ruralis 的叶绿体基因组与唯一测序的藓类植物 Physcomitrella patens 的基因组存在差异，但我们尚未确定这些差异的生物学意义。我们在基因组测序中发现的多态性为苔藓植物的精细水平系统发育研究或研究种群内个体变异提供了一个罕见的可能性（生成 DNA 标记）。
