Nock Catherine J, Hardner Craig M, Montenegro Juan D, Ahmad Termizi Ainnatul A, Hayashi Satomi, Playford Julia, Edwards David, Batley Jacqueline
Southern Cross Plant Science, Southern Cross University, Lismore, NSW, Australia.
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St Lucia, QLD, Australia.
Front Plant Sci. 2019 Mar 21;10:334. doi: 10.3389/fpls.2019.00334. eCollection 2019.
Identifying the geographic origins of crops is important for the conservation and utilization of novel genetic variation. Even so, the origins of many food crops remain elusive. The tree nut crop macadamia has a remarkable domestication history, from subtropical rain forests in Australia through Hawaii to global cultivation all within the last century. The industry is based primarily on and hybrid cultivars with Hawaiian cultivars the main contributors to world production. Sequence data from the chloroplast genome assembled using a genome skimming strategy was used to determine population structure among remnant populations of the main progenitor species, . Phylogenetic analysis of a 506 bp chloroplast SNP alignment from 64 wild and cultivated accessions identified phylogeographic structure and deep divergences between clades providing evidence for historical barriers to seed dispersal. High levels of variation were detected among wild accessions. Most Hawaiian cultivars, however, shared a single chlorotype that was also present at two wild sites at Mooloo and Mt Bauple from the northernmost distribution of the species in south-east Queensland. Our results provide evidence for a maternal genetic bottleneck during early macadamia domestication, and pinpoint the likely source of seed used to develop the Hawaiian cultivars. The extensive variability and structuring of chloroplast genomic variation detected in this study suggests much unexploited genetic diversity is available for improvement of this recently domesticated crop.
确定作物的地理起源对于新基因变异的保护和利用至关重要。即便如此，许多粮食作物的起源仍然难以确定。坚果作物澳洲坚果有着非凡的驯化历史，从上世纪起，它从澳大利亚的亚热带雨林传播至夏威夷，进而实现全球种植。该产业主要基于[此处原文缺失部分内容]以及[此处原文缺失部分内容]杂交品种，其中夏威夷品种是世界产量的主要贡献者。利用基因组重测序策略组装的叶绿体基因组序列数据，来确定主要祖先物种[此处原文缺失物种名称]残余种群之间的种群结构。对来自64个野生和栽培种质的506 bp叶绿体SNP比对进行系统发育分析，确定了系统地理学结构以及分支之间的深度分化，这为种子传播的历史障碍提供了证据。在野生种质中检测到高水平的变异。然而，大多数夏威夷品种共享单一的叶绿体单倍型，该单倍型也存在于昆士兰州东南部该物种最北分布区的穆卢和巴普尔山的两个野生地点。我们的结果为澳洲坚果早期驯化过程中的母系遗传瓶颈提供了证据，并确定了用于培育夏威夷品种的种子的可能来源。本研究中检测到的叶绿体基因组变异的广泛变异性和结构表明，这种最近驯化的作物有许多未被开发的遗传多样性可用于改良。
