L-myo-Inositol-1-phosphate synthase (EC 5.5.1.4, MIPS), an evolutionarily conserved enzyme protein, catalyzes the synthesis of inositol, which is implicated in a number of metabolic reactions in the biological kingdom. Here we report on the isolation of the gene (PINO1) for a novel salt-tolerant MIPS from the wild halophytic rice, Porteresia coarctata (Roxb.) Tateoka. Identity of the PINO1 gene was confirmed by functional complementation in a yeast inositol auxotrophic strain. Comparison of the nucleotide and deduced amino acid sequences of PINO1 with that of the homologous gene from Oryza sativa L. (RINO1) revealed distinct differences in a stretch of 37 amino acids, between amino acids 174 and 210. Purified bacterially expressed PINO1 protein demonstrated a salt-tolerant character in vitro compared with the salt-sensitive RINO1 protein as with those purified from the native source or an expressed salt-sensitive mutant PINO1 protein wherein amino acids 174 -210 have been deleted. Analysis of the salt effect on oligomerization and tryptophan fluorescence of the RINO1 and PINO1 proteins revealed that the structure of PINO1 protein is stable toward salt environment. Furthermore, introgression of PINO1 rendered transgenic tobacco plants capable of growth in 200 -300 mM NaCl with retention of ϳ40 -80% of the photosynthetic competence with concomitant increased inositol production compared with unstressed control. MIPS protein isolated from PINO1 transgenics showed salt-tolerant property in vitro confirming functional expression in planta of the PINO1 gene. To our knowledge, this is the first report of a salt-tolerant MIPS from any source.Inositols are six-carbon cyclohexane hexitols found ubiquitously in the biological kingdom, and its metabolism plays a vital role in growth regulation, membrane biogenesis, osmotolerance, and in many other processes. As phosphorylated derivatives, its role as a phosphorus store and as a "second messenger" in signal transduction pathways has long been recognized. myo-Inositol, physiologically the most favored stereoisomer among the eight possible geometric isomers of inositol, also enters into an array of biochemical reactions having diverse functions in cellular metabolism both as free and conjugated and phosphorylated or methylated forms (1-3).The primary enzyme for the synthesis of L-myo-inositol 1-phosphate from glucose 6-phosphate is L-myo-inositol-1-phosphate synthase (EC 5.5.1.4; referred to as MIPS), 1 which synthesizes L-myo-inositol 1-phosphate through an internal oxidoreduction reaction involving NAD ϩ . Free inositol is generated by dephosphorylation of the MIPS product by a specific Mg 2ϩ -dependent inositol-1-phosphate phosphatase (EC 3.1.3.25). This mechanism is followed by all myo-inositolproducing organisms throughout the phylogenetic lines, and MIPS has been identified as an evolutionarily conserved protein (4). The structural gene coding for cytosolic MIPS, termed INO1, was first identified in yeast, Saccharomyces cerevisiae (5, 6) and cloned by Klig and Henry (7)....

An efficient protocol for in vitro propagation of an aromatic and medicinal herb Ocimum basilicum L. (sweet basil) through axillary shoot proliferation from nodal explants, collected from field-grown plants, is described. High frequency bud break and maximum number of axillary shoot formation was induced in the nodal explants on Murashige and Skoog (1962) medium (MS) containing N6-benzyladenine (BA). The nodal explants required the presence of BA at a higher concentration (1.0 mg' [ -t, 4.4 ttM) at the initial stage of bud break; however, further growth and proliferation required transfer to a medium containing BA at a relatively low concentration (0.25 rag-1 ~, 1.1 ~M). Gibberellic acid (GAz) at 0.4 mg'l -~ (1.2 tiM) added to the medium along with BA (1.0 mg'l a, 4.4 p.M) markedly enhanced the frequency of bud break. The shoot clumps that were maintained on the proliferating medium for longer durations, developed inflorescences and flowered in vitro. The shoots formed in vitro were rooted on haft-strength MS supplemented with 1.0 mg'l ~ (5.0 ~M) indole-3-butyric acid (IBA). Rooted plantlets were successfully acclimated in vermi-compost inside a growth chamber and eventually established in soil. All regenerated plants were identical to the donor plants with respect to vegetative and floral morphology.

No abstract

No abstract

No abstract

No abstract

No abstract

A procedure is outlined for in vitro propagation of two medicinal herbs, Ocimum americanum L. syn. O. canum Sims (hoary basil) and Ocimum sanctum L. (holy basil), using axillary shoot buds. Multiple shoot formation was induced from shoot bud explants of both species on Murashige and Skoog medium (MS) supplemented with benzyladenine (BA). The optimum BA concentrations for shoot proliferation were 0.25 mg/l for O. americanum and 1.0 mg/l for O. sanctum. Incorporation of 0.5 mg/l gibberellic acid (GA3) along with BA in the culture medium resulted in a marked increase in the frequency of axillary branching as well as multiple shoot formation. Shoot buds collected between September through December were most responsive in culture. Shoots of O. americanum were rooted on half-strength MS supplemented with 1.0 mg/l indole-3-butyric acid (IBA), whereas O. sanctum rooted best on medium with 1.0 mg/l naphthaleneacetic acid (NAA). The plantlets were hardened off and successfully established in natural soil, where they grew and matured normally.