The pattern of Phosphate transporter 1 genes evolutionary divergence in Glycine max L

The Phosphate transporter 1 (PHT1) gene family has crucial roles in phosphate uptake, translocation, remobilization, and optimization of metabolic processes using of Pi. Gene duplications expand the size of gene families, and subfunctionalization of paralog gene pairs is a predominant tendency after gene duplications. To date, experimental evidence for the evolutionary relationships among different paralog gene pairs of a given gene family in soybean is limited.

All potential Phosphate transporter 1 genes in Glycine max L. (GmPHT1) were systematically analyzed using both bioinformatics and experimentation. The soybean PHT1 genes originated from four distinct ancestors prior to the Gamma WGT and formed 7 paralog gene pairs and a singleton gene. Six of the paralog gene pairs underwent subfunctionalization, and while GmPHT1;4 paralog gene experienced pseudogenization. Examination of long-term evolutionary changes, six GmPHT1 paralog gene pairs diverged at multiple levels, in aspects of spatio-temporal expression patterns and/or quanta, phosphates affinity properties, subcellular localization, and responses to phosphorus stress.

These characterized divergences occurred in tissue- and/or development-specific modes, or conditional modes. Moreover, they have synergistically shaped the evolutionary rate of GmPHT1 family, as well as maintained phosphorus homeostasis at cells and in the whole plant.