Genome-wide Identification, Characterization, and Expression Analysis of PHT1 Phosphate Transporters in Wheat.

Wan Teng,Yi-Ping Tong,Xue-Qiang Zhao,Xin-Ping Chen,Xue He,Yan-Yan Zhao,Yan Deng,Wen-Ying Ma

doi:10.3389/fpls.2017.00543

Abstract

The PHT1 family of phosphate (Pi) transporters mediates phosphorus (P) uptake and re-mobilization in plants. A genome-wide sequence analysis of PHT1 genes in wheat (Triticum aestivum) was conducted, and their expression locations and responses to P availability were further investigated. We cloned 21 TaPHT1 genes from the homologous alleles at TaPHT1.1 to 1.10 through screening a BAC library and amplifying genomic sequences. The TaPHT1 transporters were clustered into five branches in the phylogenetic tree of PHT1 proteins, and the TaPHT1 genes from a given branch shared high similarities in sequences, expression locations, and responses to P availability. The seven tested PHT1 genes all showed Pi-transport activity in yeast (Saccharomyces cerevisiae) cells grown under both low Pi and high Pi conditions. The expression of TaPHT1.1/1.9, 1.2, and 1.10 were root specific. The expression of these TaPHT1 genes at flowering positively correlated with P uptake after stem elongation across three P application rates and two wheat varieties in a field experiment. Therefore, modification of PHT1 expression may improve P use efficiency in a broad regime of P availability.

Highlights

Phosphorus (P) is one of the essential macronutrients for plant growth and development, and it takes part in cellular macromolecules, energy transfer reactions, and cellular metabolism
One nucleotide deletion occurred at 368 bp downstream of the start codon in TaPHT1.104B and resulted in a frame shift mutation, and TaPHT1.9-4A had a premature stop codon mutation at 810 bp downstream of the start codon, but this premature stop mutation was not found in the Chinese spring
We identified a total of 36 TaPHT1 genes named from TaPHT1.1 to TaPHT1.14 in wheat

Summary

Introduction

Phosphorus (P) is one of the essential macronutrients for plant growth and development, and it takes part in cellular macromolecules, energy transfer reactions, and cellular metabolism. Efficient acquisition of phosphate (Pi) from soil combined with efficiency translocation of Pi within plants is essential for plants to maintain adequate levels of cellular Pi necessary for normal function (Raghothama and Karthikeyan, 2005). As there is a large difference between Pi levels in plant cells (mM) and soil solution (μM), plants need to acquire Pi against a steep concentration gradient across the plasma membrane (Smith et al, 2003; Raghothama and Karthikeyan, 2005). The transmembrane transport of Pi from soils into plant cells requires a high-affinity, energy-driven transport mechanism (Smith et al, 2003). The PHT1 family of plant Pi transporters is assumed to play the predominant roles in this transmembrane transport

Objectives

Methods

Results

Conclusion