Tohoku University · Biochemistry, Genetics and Molecular Biology
Professor Amane Makino's research lab specializes in plant physiology, with a primary focus on the regulation of photosynthesis and nitrogen metabolism in C3 crops such as rice and wheat. The lab investigates how nitrogen availability influences key photosynthetic enzymes—particularly Rubisco—and their relationship to photosynthetic capacity, leaf nitrogen content, and carbon fixation. Using hydroponic systems and advanced biochemical techniques, the lab explores the physiological and molecular mechanisms underlying plant growth responses to environmental factors like elevated CO2 and nutrient supply. Their work provides critical insights into improving crop productivity through optimized nutrient use and photosynthetic efficiency.
Figures are computed from collected data and may differ slightly.
Rice ( Oryza sativa ) and wheat ( Triticum aestivum ) are the two most commercially important crops, accounting for more than 40% of global food production. They were domesticated in different climates and differ largely in their growth environments: Rice is tropically cultivated in hot, wet
In this review, we discuss the effects of elevated CO2 levels on photosynthesis in relation to the whole plant growth in terrestrial higher C3 plants. Short-term CO2 enrichment stimulates the rate of photosynthesis. Plant mass is also enhanced by CO2 enrichment. However, the effects of long-term CO2 enrichment on photosynthesis are variable. Generally, the prolonged exposure to CO2 enrichment reduces the initial stimulation of photosynthesis in many species, and frequently suppresses photosynthe
The relation between N content and ribulose-l,5-bisphosphate (RuBP) carboxylase protein was examined in the 12th leaf blade of rice. Plants were grown under different amounts of N after the emergence of the 12th leaf blade. RuBP carboxylase protein increased with leaf N during leaf expansion. The synthesis of RuBP carboxylase predominated during this period, and changes in the amounts of carboxylase synthesized until leaf death paralleled changes in the N influx to the leaves. When the carboxyla
Changes in photosynthesis and the ribulose 1,5-bisphosphate (RuBP) carboxylase level were examined in the 12th leaf blades of rice (Oryza sativa L.) grown under different N levels. Photosynthesis was determined using an open infrared gas analysis system. The level of RuBP carboxylase was measured by rocket immunoelectrophoresis. These changes were followed with respect to changes in the activities of RuBP carboxylase, ribulose 5-phosphate kinase, NADP-glyceraldehyde 3-phosphate dehydrogenase, an
The amounts of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), total chlorophyll (Chl), and total leaf nitrogen were measured in fully expanded, young leaves of wheat (Triticum aestivum L.), rice (Oryza sativa L.), spinach (Spinacia oleracea L.), bean (Phaseolus vulgaris L.), and pea (Pisum sativum L.). In addition, the activities of whole-chain electron transport and carbonic anhydrase were measured. All plants were grown hydroponically at different nitrogen concentrations. Although
The photosynthetic gas-exchange rates and various biochemical components of photosynthesis, including ribulose-1,5-bisphosphate carboxylase (Rubisco) content, cytochrome (Cyt) f content, and the activities of two sucrose synthesis enzymes, were examined in young, fully expanded leaves of rice (Oryza sativa L.) grown hydroponically in different nitrogen concentrations. The light-saturated rate of photosynthesis at an intercellular CO2 pressure of 20 Pa (CO2-limited photosynthesis) was linearly de
Changes in chlorophyll fluorescence, P700(+)-absorbance and gas exchange during the induction phase and steady state of photosynthesis were simultaneously examined in rice (Oryza sativa L.), including the rbcS antisense plants. The quantum yield of photosystem II (PhiPSII) increased more rapidly than CO(2) assimilation in 20% O(2). This rapid increase in PhiPSII resulted from the electron flux through the water-water cycle (WWC) because of its dependency on O(2). The electron flux of WWC reached
The N-use efficiency for photosynthesis was higher in a C(4) plant, maize, than in a C(3) plant, rice, including rbcS antisense rice with optimal ribulose-1,5-bisphosphate carboxylase (Rubisco) content for CO(2)-saturated photosynthesis, even when photosynthesis was measured under saturating CO(2) conditions. The N cost for the C(4) cycle enzymes in maize was not large, and the lower amount of Rubisco allowed a greater N investment in the thylakoid components. This greater content of the thylako
Rice (Oryza sativa L.) plants with decreased ribulose-1,5-bisphosphate carboxylase (Rubisco) were obtained by transformation with the rice rbcS antisense gene under the control of the rice rbcS promoter. The primary transformants were screened for the Rubisco to leaf N ratio, and the transformant with 65% wild-type Rubisco was selected as a plant set with optimal Rubisco content at saturating CO2 partial pressures for photosynthesis under conditions of high irradiance and 25[deg]C. This optimal
Proteins separated by polyacrylamide gel electrophoresis (PAGE) are usually detected by staining. In general, the proteins are measured by densitometric scanning or by eluting the dye and reading in a colorimeter. Racusenr eported a methodfor quantitative color measurement consisting in eluting Amido Black 10B with 1 n NaOH. Coomassie Brilliant Blue R-250 (CBB-R) is widely used for staining because of its high sensitivity. Recently, Tal et al.2) reported that CBB-Rbound to protein on polyacrylam
Abstract This review describes how ribulose-1,5-bisphosphate carboxylase (Rubisco) is related to photosynthesis, N economy, and whole plant growth in rice (Oryza sativa L.). Rubisco is a rate-limiting factor for potential photosynthesis under the present atmospheric air conditions. Although there is no variation in the enzymic properties of Rubisco among rice varieties including old and modern cultivars, the specific activity is 30 to 40% lower than that in other higher plants such as wheat, spi
The responses of chlorophyll fluorescence, gas exchange rate and Rubisco activation state to temperature were examined in transgenic rice plants with 130 and 35% of the wild-type (WT) Rubisco content by transformation with rbcS cDNA in sense and antisense orientations, respectively. Although the optimal temperatures of PSII quantum efficiency and CO(2) assimilation were found to be between 25 and 32 degrees C, the maximal activation state of Rubisco was found to be between 16 and 20 degrees C in
Effects of growth temperature on the photosynthetic gas-exchange rates and their underlying biochemical properties were examined in young, fully expanded leaves of rice (Oryza sativa L.). The plants were grown hydroponically under day/night temperature regimes of 18/15[deg]C, 23/18[deg]C, and 30/23[deg]C and all photosynthetic measurements were made at a leaf temperature of 25[deg]C and an irradiance of 1800 [mu]mol quanta m-2 s-1. Growth temperature affected the photosynthetic CO2 response curv
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