Takanori Maruta

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We isolated 76 high-light and heat-shock (HL + HS) stress-inducible genes, including a putative heat-shock transcription factor (HsfA2), by suppression-subtractive hybridization from Arabidopsis. The transcript level of HsfA2 was significantly increased under the several stress conditions or by the H(2)O(2) treatment. Furthermore, the induction of HsfA2(More)
The D-mannose/L-galactose pathway for the biosynthesis of vitamin C (L-ascorbic acid; AsA) has greatly improved the understanding of this indispensable compound in plants, where it plays multifunctional roles. However, it is yet to be proven whether the same pathway holds for all the different organs of plants, especially the fruit-bearing plants, at(More)
It has been known that leaves exposed to high light contain more L-ascorbic acid (AsA) than those in the shade. However, the mechanism of the light regulation of the AsA pool size in plants is largely unknown. In this work, the relationship between gene expression levels related to AsA biosynthesis and photosynthesis have been studied. When 2-week-old(More)
Heat shock transcription factor A2 (HsfA2) acts as a key component of the Hsf signaling network involved in cellular responses to various types of environmental stress. However, the mechanism governing the regulation of HsfA2 expression is still largely unknown. We demonstrated here that a heat shock element (HSE) cluster in the 5'-flanking region of the(More)
We studied molecular and functional properties of Arabidopsis phosphomannose isomerase isoenzymes (PMI1 and PMI2) that catalyze reversible isomerization between D-fructose 6-phosphate and D-mannose 6-phosphate (Man-6P). The apparent K(m) and V(max) values for Man-6P of purified recombinant PMI1 were 41.3+/-4.2 microm and 1.89 micromol/min/mg protein,(More)
The cross-talk of two redox factors, H2O2 accumulation and redox status of photosynthetic electron transport (PET) in tobacco chloroplasts, on the expression of cytosolic ascorbate peroxidase (cAPX) was studied. Transgenic tobacco plants, which expressed respectively the Escherichia coli catalase and spinach thylakoid-membrane-bound APX in chloroplasts and(More)
Though two types of chloroplastic ascorbate peroxidase (APX) located in the thylakoid membrane (tAPX) and stroma (sAPX) have been thought to be key regulators of intracellular levels of H(2)O(2), their physiological significance in the response to photooxidative stress is still under discussion. Here we characterized single mutants lacking either tAPX(More)
Recent findings have suggested that reactive oxygen species (ROS) are important signaling molecules for regulating plant responses to abiotic and biotic stress and that there exist source- and kind-specific pathways for ROS signaling. In plant cells, a major source of ROS is chloroplasts, in which thylakoid membrane-bound ascorbate peroxidase (tAPX) plays a(More)
We generated transplastomic lettuce plants expressing cyanobacterial fructose-1,6-/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) in chloroplasts. Their photosynthetic capacity and productivity were increased 1.3-fold and 1.6-fold, respectively, compared with control plants transformed with pRL200, indicating that the introduction of the enzyme affects the(More)
Vitamin E (tocopherol: Toc) is an important lipid-soluble antioxidant synthesized in chloroplasts. Among the 8 isoforms of vitamin E, α-Toc has the highest activity in humans. To generate transgenic plants with enhanced vitamin E activity, we applied a chloroplast transformation technique. Three types of the transplastomic tobacco plants (pTTC, pTTMT and(More)