Isolation and characterization of a myo-inositol 1-phosphate synthase cDNA from developing sesame (Sesamum indicum L.) seeds: functional and differential expression, and salt-induced transcription during germination

Abstract

A cDNA (SeMIPS1) encoding myo-inositol 1-phosphate synthase (EC 5.5.1.4) (MIPS) has been characterized from sesame (Sesamum indicum L. cv. Dan-Baek) seeds and its functional expression analyzed. The SeMIPS1 protein was highly homologous with those from other plant species (88-94%), while a much lower degree of sequence homology (53-62%) was found with other organisms such as humans, mouse, algae, yeast, Drosophila, bacteria and other prokaryotes. A yeast-based complementation assay in yeast mutants containing a disrupted INO1 gene for yeast MIPS confirmed that the SeMIPS1 gene encodes a functional MIPS. Phylogenetic analysis suggested that the SeM-IPS1 gene diverged as a different subfamily or family member. Southern hybridization revealed several copies of the SeMIPS1 gene present in the sesame genome and northern blotting indicated that expression of the SeMIPS1 gene may be organ specific. Salt stress during sesame seed germination had an adverse influence on transcription of SeMIPS1 and greatly reduced transcript levels as the duration of exposure to a saline environment increased and NaCl concentration increased. Germination initiation of sesame seeds was severely delayed as NaCl level increased. These results suggest that expression of SeMIPS1 is down-regulated by salt stress during sesame seed germination.

Two divergent genes encoding L‐myo‐inositol 1‐phosphate synthase1 (CaMIPS1) and 2 (CaMIPS2) are differentially expressed in chickpea

“…Earlier studies have shown that MIPS genes are differentially expressed in different organs of certain plant species like soybean (Hegeman et al 2001), Passiflora edulis (Abreu & Aragao 2007), rice (Yoshida et al 1999), S. indicum (Chun et al 2003), etc. In this study we found CaMIPS1 transcript in root, shoot, leaves and flower in fairly equal abundance, but no transcript was observed in seed, whereas CaMIPS2 transcript was observed in all examined tissues including seed, suggesting that CaMIPS2 gene also plays a key role in phytic acid biosynthesis in seed along with other aspects of inositol metabolism in chickpea (Fig.…”

“…In some plant species, multiple MIPS-coding genes have been reported. For example, seven sequences were found in maize (Larson & Raboy 1999), two in Arabidopsis (Johnson & Sussex 1995) and at least three copies in Sesamum indicum (Chun, Jin & Lee 2003). Differential expression patterns of MIPS genes have been reported in some plants including rice, Passiflora edulis, etc.…”

The Emerging Oilseed Crop Sesamum indicum Enters the “Omics” Era

“…Wherefore, numerous studies have early attempted to decipher the genetic basis of the oil yield and quality which are some key agronomic traits in sesame breeding. Even so, until 2013, the molecular mechanisms of the high oil content and quality in sesame seeds were still unclear (Jin et al, 2001; Chun et al, 2003; Suh et al, 2003; Ke et al, 2011). An association mapping of oil content, protein content, oleic acid concentration, and linoleic acid concentration based on multi-environment trials was conducted using 79 SSR, SRAP, and AFLP markers in 216 Chinese sesame accessions (Wei et al, 2013).…”

Identification and testing of reference genes for Sesame gene expression analysis by quantitative real-time PCR

“…In recent years, quantitative real-time reverse transcriptase PCR (qRT-PCR) has been used as the main analysis technique for quantification and regulating characterization of gene expression. Compared with the traditional method of Northern blot hybridization (Yukawa et al 1996; Jin et al 2001; Tai et al 2002; Chun et al 2003; Choi et al 2008; Park et al 2010), qRT-PCR is an efficient, reliable and sensitive technique for a limited number of target genes (Bustin 2000; Gachon et al 2004; Hong et al 2008; Maroufi et al 2010). To quantify the expression level of a target gene in qRT-PCR, at least one control gene, termed a reference gene, is needed for normalization.…”