Cao Chenhao, Qiu Xinbao, Yang Zhongnan, Jin Yue
Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai, 200234, China.
J Plant Res. 2025 Jan;138(1):3-17. doi: 10.1007/s10265-024-01596-3. Epub 2024 Nov 12.
UMAMIT proteins have been known as key players in amino acid transport. In Arabidopsis, functions of several UMAMITs have been characterized, but their precise mechanism, evolutionary history and functional divergence remain elusive. In this study, we conducted phylogenetic analysis of the UMAMIT gene family across key species in the evolutionary history of plants, ranging from algae to angiosperms. Our findings indicate that UMAMIT proteins underwent a substantial expansion from algae to angiosperms, accompanied by the stabilization of the EamA (the main domain of UMAMIT) structure. Phylogenetic studies suggest that UMAMITs may have originated from green algae and be divided into four subfamilies. These proteins first diversified in bryophytes and subsequently experienced gene duplication events in seed plants. Subfamily I was potentially associated with amino acid transport in seeds. Regarding subcellular localization, UMAMITs were predominantly localized in the plasma membrane and chloroplasts. However, members from clade 8 in subfamily III exhibited specific localization in the tonoplast. These members may have multiple functions, such as plant disease resistance and root development. Furthermore, our protein structure prediction revealed that the four-helix bundle motif is crucial in controlling the UMAMIT switch for exporting amino acid. We hypothesize that the specific amino acids in the amino acid binding region determine the type of amino acids being transported. Additionally, subfamily II contains genes that are specifically expressed in reproductive organs and roots in angiosperms, suggesting neofunctionalization. Our study highlights the evolutionary complexity of UMAMITs and underscores their crucial role in the adaptation and diversification of seed plants.
UMAMIT蛋白一直被认为是氨基酸转运的关键参与者。在拟南芥中，几种UMAMIT的功能已得到表征，但其精确机制、进化历史和功能分化仍不清楚。在本研究中，我们对植物进化史上从藻类到被子植物的关键物种的UMAMIT基因家族进行了系统发育分析。我们的研究结果表明，UMAMIT蛋白从藻类到被子植物经历了大量扩张，同时伴随着EamA（UMAMIT的主要结构域）结构的稳定。系统发育研究表明，UMAMIT可能起源于绿藻，并分为四个亚家族。这些蛋白首先在苔藓植物中多样化，随后在种子植物中经历了基因复制事件。亚家族I可能与种子中的氨基酸转运有关。关于亚细胞定位，UMAMIT主要定位于质膜和叶绿体。然而，亚家族III中第8进化枝的成员在液泡膜上表现出特异性定位。这些成员可能具有多种功能，如植物抗病性和根系发育。此外，我们的蛋白质结构预测表明，四螺旋束基序在控制UMAMIT输出氨基酸的开关中至关重要。我们假设氨基酸结合区域中的特定氨基酸决定了所转运氨基酸的类型。此外，亚家族II包含在被子植物的生殖器官和根中特异性表达的基因，表明发生了新功能化。我们的研究突出了UMAMIT的进化复杂性，并强调了它们在种子植物适应和多样化中的关键作用。
