13 résultats
Four putative β-amylase genes found in the Oryza sativa cDNA sequence database (KOME) were expressed in Escherichia coli. Recombinant proteins from two of these genes showed β-amylase activity. Similarly to β-amylases from other plants, the optimum pH of the recombinant rice β-amylases was about
A maize (Zea mays L.) cDNA clone (pZMB2) encoding beta-amylase was isolated from a cDNA library prepared from the aleurone RNA of germinating kernels. The cDNA encodes a predicted product of 488 amino acids with significant similarity to known beta-amylases from barley (Hordeum vulgare), rye (Secale
The expression of beta-amylase genes in rice (Oryza sativa) and its regulation by phytohormones gibberellic acid (GA) and abscisic acid (ABA) were examined. Upon germination beta-amylase is synthesized de novo in aleurone cells and (GA) is not required. Exogenous addition of GA does not enhance the
Cold stress is one of the major limiting factors for rice (Oryza sativa) productivity. Several MYB transcriptional factors have been reported as important regulators in the cold stress response, but the molecular mechanisms are largely unknown. In this study, we characterized a cold-responsive
This study aimed to investigate the potential of Rhodopseudomonas palustris C1 and Rubrivivax benzoatilyticus C31 to ameliorate As toxicity and to reduce As uptake in rice. Strain C1 was superior to strain C31 for siderophore production. The mixed culture (1: 1) was most effective in reducing the
Isoelectrofocusing, product analysis, thermal denaturation studies and affinity chromatography on cycloheptaamylose-Sephadex were used to identify the amylolytic enzymes in internodes of deepwater rice (Oryza sativa L.). Amylolytic activity in internodes of deepwater rice consists of α-amylase
The formation of multiple forms of amylases in germinating rice (Oryza sativa L. cv Kimmaze) grains was examined by means of isoelectric focusing, cross-immunoelectrophoresis, and rocket-line immunoelectrophoresis followed by a reaction of enzymic characterization by using beta-limit dextrin or
The levels of starch and dextrin, free sugars, soluble protein, and enzymes involved in starch metabolism-alpha-amylase, beta-amylase, phosphorylase, Q-enzyme, R-enzyme, and ADP-glucose starch synthetases-were assayed in the leaf sheaths and culm of the rice plant (Oryza sativa L., variety IR8)
GA is important for rice seed germination, and seed embryo growth relies on sugar supplementation via starch hydrolysis in the endosperm. Low temperature reduces the seed germination rates of rice; however, the mechanism of GA metabolism and its impact on sugar utilization of germinating seeds under
An adequate carbohydrate supply contributes to the survival of seeds under conditions of limited oxygen availability. The amount of soluble, readily fermentable carbohydrates in dry cereal seeds is usually very limited, with starch representing the main storage compound. Starch breakdown during the
To understand the effect of water stress on the remobilization of prestored carbon reserves, the changes in the activities of starch hydrolytic enzymes and sucrose-phosphate synthase (SPS) in the stems of rice (Oryza sativa L.) during grain filling were investigated. Two rice cultivars, showing high
BACKGROUND
Short-culm mutants have been widely used in breeding programs to increase lodging resistance. In barley (Hordeum vulgare L.), several hundreds of short-culm mutants have been isolated over the years. The objective of the present study was to identify the Brachytic1 (Brh1) semi-dwarfing
In rice (Oryza sativa), a specific temporary source organ, the stem, is important for grain filling, and moderate soil drying (MD) enhanced carbon reserve flow from stems to increase grain yield. The dynamics and biological relevance of DNA methylation in carbon reserve remobilization during grain