Purine salvage in plants.

Purine bases and nucleosides are produced by turnover of nucleotides and nucleic acids as well as from some cellular metabolic pathways. Adenosine released from the S-adenosyl-L-methionine cycle is linked to many methyltransferase reactions, such as the biosynthesis of caffeine and glycine betaine. Adenine is produced by the methionine cycles, which is related to other biosynthesis pathways, such those for the production of ethylene, nicotianamine and polyamines.

Do rice suspension-cultured cells treated with abscisic acid mimic developing seeds?

Starch synthesis is activated in the endosperm during seed development and also in rice suspension cells cultured with abscisic acid. In the anticipation that the mechanisms of starch synthesis are similar between the endosperm and the suspension cells cultured with abscisic acid, expression of genes involved in starch synthesis was evaluated in the suspension cells after abscisic acid treatment. However, it was found that the regulatory mechanism of starch synthesis in the suspension cells cultured with abscisic acid was different from that in developing seeds.

Functional analysis of the C-terminal region of the vacuolar cadmium-transporting rice OsHMA3.

Rice OsHMA3 is a vacuolar cadmium (Cd) transporter belonging to the P1B-ATPase family and has a long (273aa) C-terminal region. We analyzed the function of the region related to Cd using the transgenic Arabidopsis Col-0 ecotype, which is sensitive to Cd. The OsHMA3 variant containing a truncated (58aa) C-terminal region did not confer Cd tolerance, whereas an OsHMA3 variant containing a longer truncated (105aa) C-terminal region conferred Cd tolerance to transgenic Arabidopsis.

Induction of phytic acid synthesis by abscisic acid in suspension-cultured cells of rice.

A pathway of phytic acid (PA) synthesis in plants has been revealed via investigations of low phytic acid mutants. However, the regulation of this pathway is not well understood because it is difficult to control the environments of cells in the seeds, where PA is mainly synthesized. We modified a rice suspension culture system in order to study the regulation of PA synthesis.

Phytochemical profile of a Japanese black-purple rice.

Black-purple rice is becoming popular with health conscious food consumers. In the present study, the secondary metabolites in dehulled black-purple rice cv. Asamurasaki were analysed using HPLC-PDA-MS(2).

Contrasting dynamics of radial O2-loss barrier induction and aerenchyma formation in rice roots of two lengths.

Background And Aims: Many wetland species form aerenchyma and a barrier to radial O(2) loss (ROL) in roots. These features enhance internal O(2) diffusion to the root apex. Barrier formation in rice is induced by growth in stagnant solution, but knowledge of the dynamics of barrier induction and early anatomical changes was lacking.

OsHMA3, a P1B-type of ATPase affects root-to-shoot cadmium translocation in rice by mediating efflux into vacuoles.

• The cadmium (Cd) over-accumulating rice (Oryza sativa) cv Cho-Ko-Koku was previously shown to have an enhanced rate of root-to-shoot Cd translocation. This trait is controlled by a single recessive allele located at qCdT7. • In this study, using positional cloning and transgenic strategies, heavy metal ATPase 3 (OsHMA3) was identified as the gene that controls root-to-shoot Cd translocation rates.

A single recessive gene controls cadmium translocation in the cadmium hyperaccumulating rice cultivar Cho-Ko-Koku.

The heavy metal cadmium (Cd) is highly toxic to humans and can enter food chains from contaminated crop fields. Understanding the molecular mechanisms of Cd accumulation in crop species will aid production of safe Cd-free food. Here, we identified a single recessive gene that allowed higher Cd translocation in rice, and also determined the chromosomal location of the gene.

QTL mapping of clubroot resistance in radish (Raphanus sativus L.).

A QTL analysis for clubroot resistance (CR) of radish was performed using an F(2) population derived from a crossing of a CR Japanese radish and a clubroot-susceptible (CS) Chinese radish. F(3) plants obtained by selfing of F(2) plants were used for the CR tests. The potted seedlings were inoculated and the symptom was evaluated 6 weeks thereafter.

Biochemical mechanism on GABA accumulation during fruit development in tomato.

A large amount of gamma-aminobutyric acid (GABA) was found to accumulate in tomato (Solanum lycopersicum) fruits before the breaker stage. Shortly thereafter, GABA was rapidly catabolized after the breaker stage. We screened the GABA-rich tomato cultivar 'DG03-9' which did not show rapid GABA catabolism after the breaker stage.

Six-rowed barley originated from a mutation in a homeodomain-leucine zipper I-class homeobox gene.

Increased seed production has been a common goal during the domestication of cereal crops, and early cultivators of barley (Hordeum vulgare ssp. vulgare) selected a phenotype with a six-rowed spike that stably produced three times the usual grain number. This improved yield established barley as a founder crop for the Near Eastern Neolithic civilization.

Genome wide cDNA-AFLP analysis of genes rapidly induced by combined sucrose and ABA treatment in rice cultured cells.

We identified 27 genes induced by combined sucrose and ABA treatment from rice cultured cells with cDNA-AFLP. Thirteen of these up-regulated genes were induced 30 min after the co-treatment. This suite of genes includes starch biosynthesis related genes.

Identification of genes of the plant-specific transcription-factor families cooperatively regulated by ethylene and jasmonate in Arabidopsis thaliana.

The analysis of expression patterns of transcription-factor genes will be the basis for a better understanding of their biological functions in plants. In this study, we designed and developed an oligo-DNA macroarray consisting of gene-specific probes of 60-65 nucleotides for 288 transcription-factor genes, which cover COL, DOF, ERF, and NAC family genes. To investigate transcription-factor genes that are cooperatively regulated by jasmonate and ethylene in arabidopsis (Arabidopsis thaliana (L.

Studies on transcriptional regulation of endogenous genes by ERF2 transcription factor in tobacco cells.

In this study, we showed that overexpression of ethylene-responsive transcription factor (ERF) 2 activated the expression of endogenous genes that have the GCC box in their promoter region, in tobacco plants. These include not only a defense-related gene, CHN50, encoding class I basic chitinase, but also a transcriptional repressor gene, ERF3. In tobacco plants constitutively expressing ERF2:glucocorticoid receptor fusion protein, treatment with dexamethazone induced a rapid increase of ERF3 mRNA and a slow increase of CHN50 mRNA.

Genome-wide analysis of the ERF gene family in Arabidopsis and rice.

Genes in the ERF family encode transcriptional regulators with a variety of functions involved in the developmental and physiological processes in plants. In this study, a comprehensive computational analysis identified 122 and 139 ERF family genes in Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa L. subsp.

A new MADS-box gene (IbMADS10) from sweet potato (Ipomoea batatas (L.) Lam) is involved in the accumulation of anthocyanin.

A new MADS-box gene designated as IbMADS10 was cloned and its expression was characterized from sweet potato (Ipomoea batatas (L.) Lam.) cv.

Potential application of ribosomal intergenic spacer analysis to the microbial community analysis of agronomic products.

Ribosomal intergenic spacer analysis (RISA) has been applied to the microbial community analysis of agronomic products in combination with a simple and rapid DNA extraction method, consisting of a one-step extraction and two-step purification, for a variety of agronomic products. RISA appears to be a useful tool for the study of the community structures of food-associated microbes and their use as a unique fingerprinting signature for each agronomic product. Sequencing analyses of amplicons generated from RISA suggest that this method can detect conventional microbes.

Gene expression of ADP-glucose pyrophosphorylase and starch contents in rice cultured cells are cooperatively regulated by sucrose and ABA.

Six cDNA clones encoding two small subunits and four large subunits of ADP-glucose pyrophosphorylase (AGPase) were mined from the database of rice full-length cDNAs, cloned and subsequently named: OsAPS1, OsAPS2, OsAPL1, OsAPL2, OsAPL3 and OsAPL4. Expression patterns of the six genes were examined by Northern blot analysis with gene-specific probes. OsAPL3 was predominantly expressed in the middle phases of seed development, and OsAPS1, OsAPL1 and OsAPL2 were expressed later in seed development.

A new 9-lipoxygenase cDNA from developing rice seeds.

We isolated a novel C9 position specific lipoxygenase (r9-LOX1) cDNA from developing rice seeds. The enzymatic features of r9-LOX1 resembled those of rice LOX-L3 known to be contained in rice germ and to have C9-specific LOX activity. However, the expression level of the r9-LOX1 gene was higher in imbibed seeds rather than developing seeds.

The first committed step reaction of caffeine biosynthesis: 7-methylxanthosine synthase is closely homologous to caffeine synthases in coffee (Coffea arabica L.).

In coffee and tea plants, caffeine is synthesized from xanthosine via a pathway that has three methylation steps. We identified and characterized the gene encoding the enzyme for the first methylation step of caffeine biosynthesis. The full-length cDNA of coffee tentative caffeine synthase 1, CtCS1, previously isolated by the rapid amplification of cDNA ends was translated with an Escherichia coli expression system and the resultant recombinant protein was purified using Ni-NTA column.

Cloning, expression, and characterization of an antifungal chitinase from Leucaena leucocephala de Wit.

Chitinase cDNAs from Leucaena leucocephala seedlings were cloned by PCR amplification with degenerate primers based on conserved class I chitinase sequences and cDNA library screening. Two closely related chitinase cDNAs were sequenced and inferred to encode precursor proteins of 323 (KB1) and 326 (KB2) amino acids. Expression of the KB2 chitinase from a pET32a plasmid in Origami (DE3) Escherichia coli produced high chitinase activity in the cell lysate.

Isolation of a new dual-functional caffeine synthase gene encoding an enzyme for the conversion of 7-methylxanthine to caffeine from coffee (Coffea arabica L.).

In coffee and tea plants, caffeine is synthesized from xanthosine via a pathway that includes three methylation steps. We report the isolation of a bifunctional coffee caffeine synthase (CCS1) clone from coffee endosperm by reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) technique using previously reported sequence information for theobromine synthases (CTSs). The predicted amino acid sequences of CCS1 are more than 80% identical to CTSs and are about 40% similar to those of tea caffeine synthase (TCS1).

Isolation of MADS-box genes from sweet potato (Ipomoea batatas (L.) Lam.) expressed specifically in vegetative tissues.

New MADS-domain genes, IbMADS3 and IbMADS4, were isolated from pigmented and tuber-forming root tissue in sweet potato (Ipomoea batatas L.). Both genes were expressed preferentially in vegetative tissues, especially root tissues; white fibrous roots, pigmented roots, and developing tuberous roots.