Identification, expression analysis and molecular modeling of Iron deficiency specific clone 3 (Ids3) like gene in hexaploid wheat

Abstract

Graminaceous plants secrete iron (Fe) chelators called mugineic acid family phytosiderophores (MAs) from their roots for solubilisation and mobilization of unavailable ferric (Fe3+) ions from the soil. The hydroxylated forms of these phytosiderophores have been found more efficient in chelation and subsequent uptake of minerals from soil which are available in very small quantities. The genes responsible for hydroxylation of phytosiderophores have been recognized as iron deficiency-specific clone 2 (Ids2) and iron deficiency-specific clone 3 (Ids3) in barley but their presence is not reported earlier in hexaploid wheat. Hence, the present investigation was done with the aim:(i) to search for the putative Hordeum vulgare Ids3 (HvIds3) ortholog in hexaploid wheat, (ii) physical mapping of HvIds3 ortholog on wheat chromosome using cytogenetic stocks developed in the background of wheat cultivar Chinese Spring and (iii) to analyze the effect of iron starvation on the expression pattern of this ortholog at transcription level. In the present investigation, a putative ortholog of HvIds3 gene was identified in hexaploid wheat using different bioinformatics tools. Further, protein structure of TaIDS3 was modelled using homology modeling and also evaluated modelled structure behavior on nanoseconds using molecular dynamics based approach. Additionally, the ProFunc results also predict the functional similarity between the proteins of HvIds3 and its wheat ortholog (TaIds3). The physical mapping study with the use of cytogenetic stocks confines TaIds3 in the telomeric region of chromosome 7AS which supports the results obtained by bioinformatics analysis. The relative expression analysis of TaIds3 indicated that the detectable expression of TaIds3 induces after 5th day of Fe-starvation and increases gradually up to 15th day and thereafter decreases till 35th day of Fe-starvation. This reflects that Fe deficiency directly regulates the induction of TaIds3 in the roots of hexaploid wheat.