Yunnan Institute of Tropical Crops, Xishuangbanna, China.
Qingdao University of Science & Technology, Qingdao, China.
PLoS One. 2022 May 3;17(5):e0263545. doi: 10.1371/journal.pone.0263545. eCollection 2022.
Macadamia is a true dicotyledonous plant that thrives in a mild, humid, low wind environment. It is cultivated and traded internationally due to its high-quality nuts thus, has significant development prospects and scientific research value. However, information on the genetic resources of Macadamia spp. remains scanty.
The mitochondria (mt) genomes of three economically important Macadamia species, Macadamia integrifolia, M. ternifolia and M. tetraphylla, were assembled through the Illumina sequencing platform. The results showed that each species has 71 genes, including 42 protein-coding genes, 26 tRNAs, and 3 rRNAs. Repeated sequence analysis, RNA editing site prediction, and analysis of genes migrating from chloroplast (cp) to mt were performed in the mt genomes of the three Macadamia species. Phylogenetic analysis based on the mt genome of the three Macadamia species and 35 other species was conducted to reveal the evolution and taxonomic status of Macadamia. Furthermore, the characteristics of the plant mt genome, including genome size and GC content, were studied through comparison with 36 other plant species. The final non-synonymous (Ka) and synonymous (Ks) substitution analysis showed that most of the protein-coding genes in the mt genome underwent negative selections, indicating their importance in the mt genome.
The findings of this study provide a better understanding of the Macadamia genome and will inform future research on the genus.
澳洲坚果是一种真正的双子叶植物，在温和、潮湿、低风速的环境中茁壮成长。由于其高品质的坚果，它在国际上得到了广泛的种植和贸易，因此具有广阔的发展前景和重要的科学研究价值。然而，关于澳洲坚果属的遗传资源信息仍然很少。
通过 Illumina 测序平台，组装了三种经济上重要的澳洲坚果种（Macadamia integrifolia、M. ternifolia 和 M. tetraphylla）的线粒体（mt）基因组。结果表明，每个物种都有 71 个基因，包括 42 个蛋白质编码基因、26 个 tRNA 和 3 个 rRNA。对三种澳洲坚果 mt 基因组中的重复序列分析、RNA 编辑位点预测以及从叶绿体（cp）向 mt 转移的基因分析进行了研究。基于三种澳洲坚果 mt 基因组和 35 个其他物种的系统发育分析揭示了澳洲坚果的进化和分类地位。此外，通过与 36 个其他植物物种的比较，研究了植物 mt 基因组的特征，包括基因组大小和 GC 含量。最终的非同义（Ka）和同义（Ks）取代分析表明，mt 基因组中的大多数蛋白质编码基因都经历了负选择，这表明它们在 mt 基因组中的重要性。
本研究的结果为进一步了解澳洲坚果基因组提供了依据，并将为该属的未来研究提供信息。
