Department of Evolutionary Biology and Environmental Studies & Zurich-Basel Plant Science Center, University of Zurich, 8057, Zurich, Switzerland.
Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008, Zurich, Switzerland.
Nat Commun. 2020 Jun 8;11(1):2885. doi: 10.1038/s41467-020-16679-7.
The number of male gametes is critical for reproductive success and varies between and within species. The evolutionary reduction of the number of pollen grains encompassing the male gametes is widespread in selfing plants. Here, we employ genome-wide association study (GWAS) to identify underlying loci and to assess the molecular signatures of selection on pollen number-associated loci in the predominantly selfing plant Arabidopsis thaliana. Regions of strong association with pollen number are enriched for signatures of selection, indicating polygenic selection. We isolate the gene REDUCED POLLEN NUMBER1 (RDP1) at the locus with the strongest association. We validate its effect using a quantitative complementation test with CRISPR/Cas9-generated null mutants in nonstandard wild accessions. In contrast to pleiotropic null mutants, only pollen numbers are significantly affected by natural allelic variants. These data support theoretical predictions that reduced investment in male gametes is advantageous in predominantly selfing species.
精子数量对于生殖成功至关重要，且在不同物种和同一物种内存在差异。在自交植物中，雄性配子所包含的花粉粒数量减少的现象广泛存在。在这里，我们利用全基因组关联研究（GWAS）来鉴定潜在的基因座，并评估选择对拟南芥中与花粉数量相关的基因座的分子特征的影响，拟南芥主要是自交植物。与花粉数量强烈相关的区域富含选择的特征，表明存在多基因选择。我们在与关联最强的基因座上分离出 REDUCED POLLEN NUMBER1（RDP1）基因。我们使用 CRISPR/Cas9 生成的非标准野生型品系中的无效突变体进行定量互补测试来验证其效果。与多效性无效突变体不同，只有花粉数量受到自然等位变体的显著影响。这些数据支持了理论预测，即在主要是自交的物种中，减少雄性配子的投入是有利的。
