Department of Plant Sciences / MS1, Section of Crop & Ecosystem Sciences, University of California, 1 Shields Avenue, Davis, CA, 95616-8780, USA.
New Phytol. 2020 Jan;225(1):558-570. doi: 10.1111/nph.16164. Epub 2019 Oct 11.
Plant domestication has strongly modified crop morphology and development. Nevertheless, many crops continue to display atavistic characteristics that were advantageous to their wild ancestors but are deleterious under cultivation, such as pod dehiscence (PD). Here, we provide the first comprehensive assessment of the inheritance of PD in the common bean (Phaseolus vulgaris), a major domesticated grain legume. Using three methods to evaluate the PD phenotype, we identified multiple, unlinked genetic regions controlling PD in a biparental population and two diversity panels. Subsequently, we assessed patterns of orthology among these loci and those controlling the trait in other species. Our results show that different genes were selected in each domestication and ecogeographic race. A chromosome Pv03 dirigent-like gene, involved in lignin biosynthesis, showed a base-pair substitution that is associated with decreased PD. This haplotype may underlie the expansion of Mesoamerican domesticates into northern Mexico, where arid conditions promote PD. The rise in frequency of the decreased-PD haplotype may be a consequence of the markedly different fitness landscape imposed by domestication. Environmental dependency and genetic redundancy can explain the maintenance of atavistic traits under domestication.
植物驯化强烈改变了作物的形态和发育。然而,许多作物仍然表现出返祖特征,这些特征对其野生祖先有利,但在栽培条件下是有害的,例如荚果开裂(PD)。在这里,我们首次对普通菜豆(Phaseolus vulgaris)的 PD 遗传进行了全面评估,普通菜豆是一种主要的驯化豆类。我们使用三种方法来评估 PD 表型,在一个双亲群体和两个多样性面板中鉴定了控制 PD 的多个、非连锁遗传区域。随后,我们评估了这些基因座与控制其他物种中该性状的基因座之间的同源性模式。我们的研究结果表明,不同的基因在每次驯化和生态地理种族中都被选择。一个参与木质素生物合成的 Pv03 导向蛋白样基因发生了碱基对替换,与 PD 降低有关。这种单倍型可能是中美洲驯化品种扩展到墨西哥北部的基础,在那里干旱条件促进了 PD。降低 PD 单倍型的频率升高可能是驯化带来的明显不同的适应度景观的结果。环境依赖性和遗传冗余可以解释驯化过程中返祖特征的维持。