Ocean School, Yantai University, Yantai 264005, PR China.
Shandong Marine Resources and Environment Research Institute, Shandong Provincial Key Laboratory of Restoration for Marine Ecology, Yantai 264006, PR China.
Genomics. 2024 Sep;116(5):110940. doi: 10.1016/j.ygeno.2024.110940. Epub 2024 Sep 18.
Seagrasses are ideal for studying plant adaptation to marine environments. In this study, the mitochondrial (mt) and chloroplast (cp) genomes of Ruppia sinensis were sequenced. The results showed an extensive gene loss in seagrasses, including a complete loss of cp-rpl19 genes in Zosteraceae, most cp-ndh genes in Hydrocharitaceae, and mt-rpl and mt-rps genes in all seagrasses, except for the mt-rpl16 gene in Phyllospadix iwatensis. Notably, most ribosomal protein genes were lost in the mt and cp genomes. The deleted cp genes were not transferred to the mt genomes through horizontal gene transfer. Additionally, a significant DNA transfer between seagrass organelles was found, with the mt genomes of Zostera containing numerous sequences from the cp genome. Rearrangement analyses revealed an unreported inversion of the cp genome in R. sinensis. Moreover, four positively selected genes (atp8, nad5, atp4, and ccmFn) and five variable regions (matR, atp4, atp8, rps7, and ccmFn) were identified.
海草是研究植物对海洋环境适应的理想选择。本研究对菹草的线粒体（mt）和叶绿体（cp）基因组进行了测序。结果表明，海草中存在广泛的基因丢失现象，包括在藤草科中完全丢失了 cp-rpl19 基因，在水鳖科中大多数 cp-ndh 基因，以及除了 iwatensis 叶底珠中的 mt-rpl16 基因之外，所有海草中的 mt-rpl 和 mt-rps 基因。值得注意的是，大多数核糖体蛋白基因在 mt 和 cp 基因组中丢失。缺失的 cp 基因并没有通过水平基因转移转移到 mt 基因组中。此外，还发现了海草细胞器之间的大量 DNA 转移，其中 Zostera 的 mt 基因组包含了来自 cp 基因组的许多序列。重排分析揭示了菹草 cp 基因组中一种未报告的倒位。此外，鉴定出了四个正选择基因（atp8、nad5、atp4 和 ccmFn）和五个可变区（matR、atp4、atp8、rps7 和 ccmFn）。
