title: Differential expression of structural genes for the late phase of phytic acid biosynthesis in developing seeds of wheat (Triticum aestivum L.).
abstract: In cereals, phytic acid (PA) or inositol hexakisphosphate (IP6) is a well-known phosphate storage compound as well as major chelator of important micronutrients (iron, zinc, calcium, etc.). Genes involved in the late phases of PA biosynthesis pathway are known in crops like maize, soybeans and barley but none have been reported from wheat. Our in silico analysis identified six wheat genes that might be involved in the biosynthesis of inositol phosphates. Four of the genes were inositol tetraphosphate kinases (TaITPK1, TaITPK2, TaITPK3, and TaITPK4), and the other two genes encode for inositol triphosphate kinase (TaIPK2) and inositol pentakisphosphate kinase (TaIPK1). Additionally, we identified a homolog of Zmlpa-1, an ABCC subclass multidrug resistance-associated transporter protein (TaMRP3) that is putatively involved in PA transport. Analyses of the mRNA expression levels of these seven genes showed that they are differentially expressed during seed development, and that some are preferentially expressed in aleurone tissue. These results suggest selective roles during PA biosynthesis, and that both lipid-independent and -dependent pathways are active in developing wheat grains. TaIPK1 and TaMRP3 were able to complement the yeast ScΔipk1 and ScΔycf1 mutants, respectively, providing evidence that the wheat genes have the expected biochemical functions. This is the first comprehensive study of the wheat genes involved in the late phase of PA biosynthesis. Knowledge generated from these studies could be utilized to develop strategies for generating low phyate wheat.
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Kaushal Kumar
authors.initials: KK
authors.lastname: Bhati
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Sipla
authors.initials: S
authors.lastname: Aggarwal
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Shivani
authors.initials: S
authors.lastname: Sharma
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Shrikant
authors.initials: S
authors.lastname: Mantri
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Sudhir P
authors.initials: SP
authors.lastname: Singh
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Sherry
authors.initials: S
authors.lastname: Bhalla
authors.affiliation: Department of Biotechnology, Panjab University, Punjab, India.
authors.forename: Jagdeep
authors.initials: J
authors.lastname: Kaur
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Siddharth
authors.initials: S
authors.lastname: Tiwari
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Joy K
authors.initials: JK
authors.lastname: Roy
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Tuli
authors.affiliation: National Agri-Food Biotechnology Institute, Department of Biotechnology, Government of India, C-127, Industrial Area, S.A.S. Nagar, Phase 8, Mohali 160071, Punjab, India. Electronic address: pandeyak@nabi.res.in.
authors.forename: Ajay K
authors.initials: AK
authors.lastname: Pandey
mesh_terms: D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D010770:Phosphotransferases / Q000235:genetics* / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D010833:Phytic Acid / Q000096:biosynthesis*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012639:Seeds / Q000254:growth & development / Q000378:metabolism*; D014908:Triticum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D010833:Phytic Acid; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C064990:inositol pentakisphosphate kinase
keywords: Gene expression; Inositol phosphate kinases; Multidrug resistance protein; Phytic acid pathway; Seed development; Triticum aestivum