Li Jin, Cullis Christopher
Department of Biology, Case Western Reserve University, Cleveland, OH, United States.
Front Plant Sci. 2023 Jan 31;13:1025408. doi: 10.3389/fpls.2022.1025408. eCollection 2022.
(marama bean) is an important orphan legume from southern Africa that has long been considered to have the potential to be domesticated as a crop. The chloroplast genomes of 84 marama samples collected from various geographical locations in Namibia and Pretoria were compared in this study. The cp genomes were analyzed for diversity, including SNPs, indels, structural alterations, and heteroplasmy. The marama cp genomes ranged in length from 161,537 bp to 161,580 bp and contained the same sets of genes, including 84 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The genes and , and the intergenic spacers and were found to be more diverse than other regions of the marama plastome. 15 haplotypes were found to be divided into two groups, differing at 122 loci and at a 230 bp inversion. One type appears to have greater variability within the major genome present, and variations amongst individuals with this type of chloroplast genome seems to be distributed within specific geographic regions but with very limited sampling for some regions. However, deep sequencing has identified that within most of the individuals, both types of chloroplast genomes are present, albeit one is generally at a very low frequency. The inheritance of this complex of chloroplast genomes appears to be fairly constant, providing a conundrum of how the two genomes co-exist and are propagated through generations. The possible consequences for adaptation to the harsh environment in which survives are considered. The results pave the way for marama variety identification, as well as for understanding the origin and evolution of the bean.
（非洲薯蓣豆）是一种来自非洲南部的重要孤生豆类，长期以来一直被认为有作为作物被驯化的潜力。本研究比较了从纳米比亚和比勒陀利亚不同地理位置采集的84个非洲薯蓣豆样本的叶绿体基因组。对叶绿体基因组进行了多样性分析，包括单核苷酸多态性（SNP）、插入缺失、结构改变和异质性。非洲薯蓣豆叶绿体基因组长度在161,537 bp至161,580 bp之间，包含相同的基因集，包括84个蛋白质编码基因、37个tRNA基因和8个rRNA基因。发现基因 和 以及基因间隔区 和 比非洲薯蓣豆质体基因组的其他区域更多样化。发现15个单倍型分为两组，在122个位点和一个230 bp的倒位处存在差异。一种类型在主要基因组内似乎具有更大的变异性，具有这种叶绿体基因组类型的个体之间的变异似乎分布在特定地理区域，但某些区域的采样非常有限。然而，深度测序已确定在大多数个体中，两种类型的叶绿体基因组都存在，尽管其中一种通常频率非常低。这种叶绿体基因组复合体的遗传似乎相当稳定，这就产生了一个难题，即这两种基因组如何共存并代代相传。考虑了其对 所生存的恶劣环境的适应可能产生的后果。这些结果为非洲薯蓣豆品种鉴定以及了解该豆类的起源和进化铺平了道路。
