State Key Laboratory of Crop Stress Biology for Arid Areas, College of Agronomy, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
BMC Genomics. 2020 Jun 5;21(1):391. doi: 10.1186/s12864-020-6729-3.
Nitrogen is an indispensable nutrient for plant growth. It is used and transported in the form of amino acids in living organisms. Transporting amino acids to various parts of plants requires relevant transport proteins, such as amino acid permeases (AAPs), which were our focus in this study.
We found that 5 AAP genes were present in Chlorophyte species and more AAP genes were predicted in Bryophyta and Lycophytes. Two main groups were defined and group I comprised 5 clades. Our phylogenetic analysis indicated that the origin of clades 2, 3, and 4 is Gymnospermae and that these clades are closely related. The members of clade 1 included Chlorophyta to Gymnospermae. Group II, as a new branch consisting of non-seed plants, is first proposed in our research. Our results also indicated that the AAP family was already present in Chlorophyta and then expanded accompanying the development of vasculature. Concurrently, the AAP family experienced multiple duplication events that promoted the generation of new functions and differentiation of sub-functions.
Our findings suggest that the AAP gene originated in Chlorophyta, and some non-seed AAP genes clustered in one group. A second group, which contained plants of all evolutionary stages, indicated the evolution of AAPs. These new findings can be used to guide future research.
氮是植物生长所必需的营养物质。它在生物体中以氨基酸的形式被利用和运输。将氨基酸运输到植物的各个部位需要相关的运输蛋白，如氨基酸渗透酶（AAP），这是我们在本研究中的重点。
我们发现绿藻物种中有 5 个 AAP 基因，而在苔藓植物和石松植物中预测到更多的 AAP 基因。我们定义了两个主要的组，其中第一组包含 5 个分支。我们的系统发育分析表明，分支 2、3 和 4 的起源是裸子植物，这些分支密切相关。分支 1 的成员包括从绿藻到裸子植物。第二组作为一个由非种子植物组成的新分支，是我们首次提出的。我们的研究结果还表明，AAP 家族已经存在于绿藻中，然后随着维管系统的发育而扩张。同时，AAP 家族经历了多次重复事件，促进了新功能的产生和亚功能的分化。
我们的研究结果表明，AAP 基因起源于绿藻，而一些非种子 AAP 基因聚集在一组中。包含所有进化阶段植物的第二组表明了 AAP 的进化。这些新发现可以用于指导未来的研究。
