TpIRT1 is a transition metal transporter in Polish Wheat (Triticum
polonicum L.) with a broad substrate specificity
Abstract
Uptake and internal transport of micronutrients are essential for plant
growth, development, and yield. In this regard, Iron Regulated
Transporters (IRTs) from the ZIP (Zinc-regulated, iron-regulated
transporter-like proteins) family play an important role in transition
metal uptake. The majority of studies have been focused on IRT1-like
proteins in diploid species, but few in polyploids. Here, we studied the
function of TpIRT1A and TpIRT1B homoeologs in a tetraploid crop, Polish
wheat (Triticum polonicum). Our results highlighted the importance of
TpIRT1 in the uptake and translocation of Fe, Mn, Co, and Cd with direct
implications for wheat yield potential. Both TpIRT1A and TpIRT1B were
located at the plasma membrane and internal vesicles in Arabidopsis
protoplasts, and responsible for Cd and Co sensitivity in yeast. The
over-expression of TpIRT1B in A. thaliana increased Fe, Mn, Co, and Cd
concentration in its tissues and improved plant growth under Fe, Mn, and
Co deficiencies, while caused more sensitive to Cd than wild-type plant.
Functional analysis of IRT1 homoeologs from tetraploid and diploid
ancestral wheat species in yeast disclosed four distinct amino acid
residues in TdiIRT1B (T. dicoccum) and TtuIRT1B (T. turgidum). Together,
these results increase the knowledge of IRT1 function in a global crop,
wheat.