Department of Gene Expression, Faculty of Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
Sci Rep. 2024 Jan 18;14(1):1611. doi: 10.1038/s41598-024-51626-2.
SQUAMOSA-PROMOTER BINDING PROTEIN-LIKE (SPL) genes encode plant-specific transcription factors which are important regulators of diverse plant developmental processes. We took advantage of available genome sequences of streptophyte algae representatives to investigate the relationships of SPL genes between freshwater green algae and land plants. Our analysis showed that streptophyte algae, hornwort and liverwort genomes encode from one to four SPL genes which is the smallest set, in comparison to other land plants studied to date. Based on the phylogenetic analysis, four major SPL phylogenetic groups were distinguished with Group 3 and 4 being sister to Group 1 and 2. Comparative motif analysis revealed conserved protein motifs within each phylogenetic group and unique bryophyte-specific motifs within Group 1 which suggests lineage-specific protein speciation processes. Moreover, the gene structure analysis also indicated the specificity of each by identifying differences in exon-intron structures between the phylogenetic groups, suggesting their evolutionary divergence. Since current understanding of SPL genes mostly arises from seed plants, the presented comparative and phylogenetic analyzes from freshwater green algae and land plants provide new insights on the evolutionary trajectories of the SPL gene family in different classes of streptophytes.
SPL 基因编码植物特异性转录因子，是多种植物发育过程的重要调控因子。我们利用已有的绿藻和陆生植物的基因组序列，研究了 SPL 基因在这些生物之间的关系。我们的分析表明，相较于迄今为止研究过的其他陆生植物，绿藻、角苔和地钱基因组编码的 SPL 基因数量为 1-4 个，是最少的。基于系统发育分析，区分出了四个主要的 SPL 系统发育群，第 3 组和第 4 组与第 1 组和第 2 组是姐妹群。比较基序分析显示，每个系统发育群内都有保守的蛋白基序，而第 1 组内有独特的苔藓植物特异性基序，这表明存在谱系特异性的蛋白特化过程。此外，基因结构分析也表明了各群的特异性，通过识别系统发育群之间的外显子-内含子结构差异来确定，表明它们在进化上已经分化。由于目前对 SPL 基因的认识主要来自种子植物，因此，本研究从淡水绿藻和陆生植物中进行的比较和系统发育分析，为不同类绿藻中 SPL 基因家族的进化轨迹提供了新的见解。
