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Front. Plant Sci. | doi: 10.3389/fpls.2018.00259

RNAi-mediated downregulation of inositol pentakisphosphate kinase (IPK1) in wheat grains decreases phytic acid levels and increases Fe and Zn accumulation

  • 1National Agri-Food Biotechnology Institute, India
  • 2Copenhagen Plant Science Centre (CPSC), Denmark

Enhancement of micronutrient bioavailability is crucial to address the malnutrition in the developing countries. Various approaches employed to address the micronutrient bioavailability are showing promising signs, especially in cereal crops. Phytic acid (PA) is considered as a major antinutrient due to its ability to chelate important micronutrients and thereby restricting their bioavailability. Therefore, manipulating PA biosynthesis pathway has largely been explored to overcome the negative impact in different crop species. Recently, we reported that functional wheat inositol pentakisphosphate kinase (TaIPK1) is involved in PA biosynthesis, however the functional roles of the IPK1 gene in wheat remains elusive. In this study, RNAi-mediated gene silencing was performed for IPK1 transcripts in hexaploid wheat. Four non-segregating RNAi lines of wheat were selected for detailed study (S3-D-6-1; S6-K-3-3; S6-K-6-10 and S16-D-9-5). Homozygous transgenic RNAi lines at T4 seeds with a decreased transcript of TaIPK1 showed 28%-56% reduction of the PA. Silencing of IPK1 also resulted in increased free phosphate in mature grains. Although, no phenotypic changes in the spike was observed but, lowering of grain PA resulted in the reduced number of seeds per spikelet. The lowering of grain PA was also accompanied by a significant increase in iron (Fe) and zinc (Zn) content, thereby enhancing their molar ratios (Zn:PA and Fe:PA). Overall, this work suggests that IPK1 is a promising candidate for employing genome editing tools to address the mineral accumulation in wheat grains.

Keywords: Phytic Acid, Triticum aestivum, inositol pentakisphosphate kinase, Gene Silencing, wheat transformation.

Received: 12 Dec 2017; Accepted: 14 Feb 2018.

Edited by:

Hatem ROUACHED, Institut National de la Recherche Agronomique (INRA), France

Reviewed by:

Ping Lan, Institute of Soil Science (CAS), China
Kulvinder S. Gill, Washington State University, United States
Sebastian Gasparis, Plant Breeding and Acclimatization Institute (IHAR), Poland  

Copyright: © 2018 Aggarwal, Kumar, Bhati, Kaur, Shukla, Tiwari and PANDEY. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. AJAY K. PANDEY, National Agri-Food Biotechnology Institute, Sector-81, Mohali, 140306, Punjab, India, pandeyak@nabi.res.in