Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany.
Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706, USA.
Plant Physiol. 2021 Apr 2;185(3):857-875. doi: 10.1093/plphys/kiaa086.
The emergence of type III polyketide synthases (PKSs) was a prerequisite for the conquest of land by the green lineage. Within the PKS superfamily, chalcone synthases (CHSs) provide the entry point reaction to the flavonoid pathway, while LESS ADHESIVE POLLEN 5 and 6 (LAP5/6) provide constituents of the outer exine pollen wall. To study the deep evolutionary history of this key family, we conducted phylogenomic synteny network and phylogenetic analyses of whole-genome data from 126 species spanning the green lineage including Arabidopsis thaliana, tomato (Solanum lycopersicum), and maize (Zea mays). This study thereby combined study of genomic location and context with changes in gene sequences. We found that the two major clades, CHS and LAP5/6 homologs, evolved early by a segmental duplication event prior to the divergence of Bryophytes and Tracheophytes. We propose that the macroevolution of the type III PKS superfamily is governed by whole-genome duplications and triplications. The combined phylogenetic and synteny analyses in this study provide insights into changes in the genomic location and context that are retained for a longer time scale with more recent functional divergence captured by gene sequence alterations.
III 型聚酮合酶（PKSs）的出现是绿色植物谱系征服陆地的先决条件。在 PKS 超家族中，查尔酮合酶（CHSs）提供了黄酮类途径的入口反应，而LESS ADHESIVE POLLEN 5 和 6（LAP5/6）则提供了花粉外壁外层的成分。为了研究这个关键家族的深层进化历史，我们对涵盖绿色植物谱系的 126 个物种的全基因组数据进行了基因组同线性网络和系统发育分析，包括拟南芥、番茄（Solanum lycopersicum）和玉米（Zea mays）。这项研究将基因序列变化与基因在基因组中的位置和上下文结合起来进行研究。我们发现，CHS 和 LAP5/6 同源物这两个主要分支在苔藓植物和维管植物分化之前，通过一个片段重复事件早期进化而来。我们提出，III 型 PKS 超家族的宏观进化受全基因组加倍和三倍化的控制。本研究中的综合系统发育和同线性分析为基因序列变化所捕获的更近期功能分化提供了对基因组位置和上下文变化的深入了解，这些变化在更长的时间尺度上得以保留。
