Cloning & Transgenesis
Open Access

Abstract

Isolation and Characterization of Inositol Tetraphosphate 1-Kinase (AhITPK1) and Inositol 1,4,5-Tris-Phosphate Kinase (AhIPK2) Gene in Peanut

Ajay BC, Ananga A, Kambiranda D, Obuya J, Bera SK and Tsolova V

In the current study, partial cDNA clones of inositol tetraphosphate 1-kinase (ITPK1) and inositol 1,4,5-trisphosphate kinase/inositol polyphosphate multikinase (IPK2), were isolated from embryo using RT-PCR and designated as AhITPK1 and AhIPK2 isoforms of the gene. The partial cDNA sequence of AhITPK1 and AhIPK2 genes have an open reading frame (ORF) of 1146 and 891bp respectively and showed high similarity to other plant genes. AhITPK1 shared high homology with Aradu. Q95MC of Arachis duranensis, had a single exon with no introns and belonged to ATP-grasp family of proteins. AhIPK2 shared high similarity with Aradu.24V9G of A. duranensis and contained three exons with 5’ and 3’ UTR’s on either side. Unlike other IPK2 genes, AhIPK2 possessed conserved domains such as PxxxDxKxG and [L/M][I/V]D[F/L][A/G][H/K]. Phylogenetic analysis grouped AhITPK1 with A. duranensis, A. ipinensis and Oryza brachyantha into one cluster, whereas AhIPK2 was grouped along with Cucumis melo and C. sativus. Evolutionarily, AhITPK1 and AhIPK2 were genetically distinct from other plant genera. Furthermore, real-time PCR analysis revealed high expression of AhITPK1 and AhIPK2 genes in the peanut embryo and flower bud. For the first time AhITPK1 (KR778986) and AhIPK2 (KR778988) genes belonging to phytic acid pathway from Arachis hypogaea were identified and characterized the expression pattern of these two isoforms on different tissues. These genes were found to be abundant in flower bud and embryo. Results suggest that embryo development significantly influences the expression of the two AhIPK isoforms in peanut. Evolutionarily they were found to be distinct from their parental species. This study is an important step toward understanding the role of these two AhIPK isoforms in phytic acid synthesis. However, future research involving RNAi-based functional characterization is warranted to establish their link to embryo development in peanut.