Phylogenetic Relationships within Cation Transporter Families of Arabidopsis

TLDR

Cationic nutrient uptake and translocation are vital for plant growth, and roughly 5 % of the Arabidopsis genome encodes ~880 membrane transport proteins across 46 families, many of which remain unassigned. We performed phylogenetic analyses of over 150 cation transport proteins from well‑characterized families such as K⁺ transporters, Na⁺ transporters, Ca²⁺ antiporters, CNG channels, CDF proteins, NRAMPs, and ZIPs. The resulting phylogenetic trees reveal extensive diversification, with many closely related isoforms and distinct subfamilies, and the PlantsT database now provides alignments and chromosomal locations for further study.

Abstract

Abstract Uptake and translocation of cationic nutrients play essential roles in physiological processes including plant growth, nutrition, signal transduction, and development. Approximately 5% of the Arabidopsis genome appears to encode membrane transport proteins. These proteins are classified in 46 unique families containing approximately 880 members. In addition, several hundred putative transporters have not yet been assigned to families. In this paper, we have analyzed the phylogenetic relationships of over 150 cation transport proteins. This analysis has focused on cation transporter gene families for which initial characterizations have been achieved for individual members, including potassium transporters and channels, sodium transporters, calcium antiporters, cyclic nucleotide-gated channels, cation diffusion facilitator proteins, natural resistance-associated macrophage proteins (NRAMP), and Zn-regulated transporter Fe-regulated transporter-like proteins. Phylogenetic trees of each family define the evolutionary relationships of the members to each other. These families contain numerous members, indicating diverse functions in vivo. Closely related isoforms and separate subfamilies exist within many of these gene families, indicating possible redundancies and specialized functions. To facilitate their further study, the PlantsT database (http://plantst.sdsc.edu) has been created that includes alignments of the analyzed cation transporters and their chromosomal locations.