Jarvis David E, Maughan Peter J, DeTemple Joseph, Mosquera Veronica, Li Zheng, Barker Michael S, Johnson Leigh A, Whipple Clinton J
Plant and Wildlife Sciences Department, Brigham Young University, USA.
Biology Department, Brigham Young University, USA.
Genome Biol Evol. 2022 Mar 2;14(3). doi: 10.1093/gbe/evac017.
Substantial morphological variation in land plants remains inaccessible to genetic analysis because current models lack variation in important ecological and agronomic traits. The genus Gilia was historically a model for biosystematics studies and includes variation in morphological traits that are poorly understood at the genetic level. We assembled a chromosome-scale reference genome of G. yorkii and used it to investigate genome evolution in the Polemoniaceae. We performed QTL (quantitative trait loci) mapping in a G. yorkii×G. capitata interspecific population for traits related to inflorescence architecture and flower color. The genome assembly spans 2.75 Gb of the estimated 2.80-Gb genome, with 96.7% of the sequence contained in the nine largest chromosome-scale scaffolds matching the haploid chromosome number. Gilia yorkii experienced at least one round of whole-genome duplication shared with other Polemoniaceae after the eudicot paleohexaploidization event. We identified QTL linked to variation in inflorescence architecture and petal color, including a candidate for the major flower color QTL-a tandem duplication of flavanol 3',5'-hydroxylase. Our results demonstrate the utility of Gilia as a forward genetic model for dissecting the evolution of development in plants including the causal loci underlying inflorescence architecture transitions.
由于目前的模型缺乏重要生态和农艺性状的变异，陆地植物中大量的形态变异仍无法进行遗传分析。吉莉草属（Gilia）在历史上是生物系统学研究的模式属，其形态性状存在变异，但在遗传水平上却知之甚少。我们组装了约克吉莉草（G. yorkii）的染色体水平参考基因组，并利用它来研究花荵科的基因组进化。我们在约克吉莉草×头状吉莉草（G. capitata）种间群体中对与花序结构和花色相关的性状进行了QTL（数量性状基因座）定位。基因组组装跨越了估计2.80 Gb基因组中的2.75 Gb，96.7%的序列包含在九个最大的染色体水平支架中，与单倍体染色体数匹配。在真双子叶植物古六倍体化事件之后，约克吉莉草经历了至少一轮与其他花荵科植物共有的全基因组复制。我们鉴定出了与花序结构和花瓣颜色变异相关的QTL，包括主要花色QTL的一个候选基因——黄烷醇3',5'-羟化酶的串联重复。我们的结果证明了吉莉草作为正向遗传模型在剖析植物发育进化方面的实用性，包括花序结构转变背后的因果基因座。
