Family-1 UDP-glycosyltransferases, designated as UGTs, glycosylate key cellular metabolites into compounds with improved stability, solubility and transport to regulate plant growth and development in various metabolic pathways. However, little is known about the molecular and functional characteristics of UGT family in an aquatic plant and how it contributes to the Nelumbo nucifera ecotypic differentiation. Therefore, we performed a genome-wide investigation of 108 candidate UGT genes distributing on all eight lotus chromosomes, encompassing 16 distinct phylogenetic groups (A–P). These UGT groups feature different molecular weights, subcellular localizations and evolutionary rates. Intra-specific collinearity analysis further suggests that the expansion of the UGT family in lotus is mainly driven by tandem duplication and whole-genome duplication. Further, expression analysis of 54 RNA-seq samples from ten different lotus tissues suggests that expression of most UGT family members exhibits tissue or developmental-stage specificity, and UGTs expressed in reproductive organs (tissues) evolve much faster than those expressed in vegetative organs. More interestingly, key UGT genes being differentially regulated between temperate and tropical lotus (ecotypes) were uncovered during the seedling stage, indicating that UGTs associated with hormone synthesis and transport likely contribute to early differentiation between lotus ecotypes. Overall, our systematic expression and evolutionary analyses not only characterize the expression, functional diversity and evolutionary dynamics of the UGT family in an aquatic plant but also provide insight into the roles of the UGT family underlying the differentiation of the lotus ecotypes.

Family-1 UDP-糖基转移酶（称为UGT）可将关键的细胞代谢物糖基化为具有改善的稳定性，溶解性和转运性的化合物，以调节植物在各种代谢途径中的生长和发育。然而，关于水生植物中UGT家族的分子和功能特性及其如何对莲莲的贡献知之甚少。生态型分化。因此，我们对分布在所有八个莲花染色体上的108个候选UGT基因进行了全基因组研究，涵盖了16个不同的系统发育群体（A–P）。这些UGT基团具有不同的分子量，亚细胞定位和进化速率。种内共线性分析进一步表明，莲花中UGT家族的扩展主要由串联重复和全基因组重复驱动。此外，对来自十个不同莲花组织的54个RNA-seq样品的表达分析表明，大多数UGT家族成员的表达均表现出组织或发育阶段的特异性，并且生殖器官（组织）中表达的UGT的进化要快于营养器官中表达的UGT。更有趣的是 在苗期未发现温带和热带荷花（生态型）之间差异调控的关键UGT基因，这表明与激素合成和运输相关的UGT可能有助于荷花生态型之间的早期分化。总体而言，我们的系统表达和进化分析不仅表征了UGT家族在水生植物中的表达，功能多样性和进化动力学，而且还洞悉了UGT家族在莲花生态型分化中的作用。