Generation of high iron content wheat mutants and expression analysis of the genes involved in iron accumulation and ethylene response

Wheat (Triticum aestivum L.) is one of the most important staple crops, feeding one-third of the global population. Although some progress has been made on the Fe biofortification aimed at increasing the levels of the essential mineral in the staple crop, little is known about the molecular regulations of the Fe accumulation-associated gene expressions in the wheat plant. In the present study, two wheat mutant lines with high ferric contents were identified. Transcriptomic analysis indicated that the differentiated expression genes (DEGs) were involved in different biological processes such as catalytic reaction, translation, biologic regulations, biosynthesis of secondary metabolites, and stress signaling. Further study revealed that the responsible genes for Fe homeostasis such as TaFIBP (encoding a ferric ion binding protein), TaZIP29 (a ZRT/IRT-like protein (ZIP) encoding gene) and TaYSL1 (wheat homologue of the Arabidopsis yellow stripe-like protein encoding gene) were highly induced when treated with exogenous Fe in the wheat mutant lines. In addition, it was observed that the ethylene sensitivity of high iron content wheat mutants were obviously altered. The transcript levels of the ethylene responsive genes (TaERF1, 2, 3, 4, 6) were significantly affected in the wheat mutant lines, suggesting that ethylene may participate in regulation of the iron accumulation in wheat. All these results advance our understanding of the molecular regulations in the Fe accumulation of wheat.