Down-regulation of wheat Rubisco activase isoforms expression by virus-induced gene silencing.

Rubisco activase (Rca) is an essential photosynthetic enzyme that removes inhibitors from the catalytic sites of the carboxylating enzyme Rubisco. In wheat, Rca is composed of one longer 46 kDa α-isoform and two shorter 42 kDa β-isoforms encoded by the genes and . produces a single transcript from which a short 1β-isoform is expressed, whereas two alternative transcripts are generated from directing expression of either a long 2α-isoform or a short 2β-isoform.

Removal of redox-sensitive Rubisco Activase does not alter Rubisco regulation in soybean.

Rubisco activase (Rca) facilitates the catalytic repair of Rubisco, the CO-fixing enzyme of photosynthesis, following periods of darkness, low to high light transitions or stress. Removal of the redox-regulated isoform of Rubisco activase, Rca-α, enhances photosynthetic induction in Arabidopsis and has been suggested as a strategy for the improvement of crops, which may experience frequent light transitions in the field; however, this has never been tested in a crop species. Therefore, we used RNAi to reduce the Rca-α content of soybean (Glycine max cv.

The relative abundance of wheat Rubisco activase isoforms is post-transcriptionally regulated.

Diurnal rhythms and light availability affect transcription-translation feedback loops that regulate the synthesis of photosynthetic proteins. The CO-fixing enzyme Rubisco is the most abundant protein in the leaves of major crop species and its activity depends on interaction with the molecular chaperone Rubisco activase (Rca). In Triticum aestivum L.

Rubisco activation by wheat Rubisco activase isoform 2β is insensitive to inhibition by ADP.

Rubisco activase (Rca) is a catalytic chaperone that remodels the active site, promotes the release of inhibitors and restores catalytic competence to Rubisco. Rca activity and its consequent effect on Rubisco activation and photosynthesis are modulated by changes to the chloroplast environment induced by fluctuations in light levels that reach the leaf, including redox status and adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio. The (wheat) genome encodes for three Rca protein isoforms: 1β (42.

Assessment of the role of silicon in the Cu-tolerance of the C4 grass Spartina densiflora.

An experiment was designed to investigate the effect of silicon supply (0 and 500 μM) on Spartina densiflora plants grown at two copper (Cu) concentrations: 0 and 15 mM. Growth parameters together with total concentrations of calcium, Cu, potassium, magnesium, manganese, sodium and nitrogen were determined in roots and leaves. Photosynthetic traits were followed by measurement of leaf gas exchange, efficiency of PSII biochemistry, total content of photosynthetic pigments and concentration and carbamylation of Rubisco sites concentration ([Rubisco]).

Effects of long-term individual and combined water and temperature stress on the growth of rice, wheat and maize: relationship with morphological and physiological acclimation.

This study evaluates the long-term individual and combined effects of high temperature (HT) and water deficit (WD) stress on plant growth, leaf gas-exchange and water use efficiency in cultivars of the three most important crops worldwide, rice, wheat and maize. Total plant biomass (B ) accumulation decreased under all treatments, being the combined HT-WD treatment the most detrimental in all three species. Although decreases in B correlated with adjustments in biomass allocation patterns (i.

Photosynthetic characterization of Rubisco transplantomic lines reveals alterations on photochemistry and mesophyll conductance.

Improving Rubisco catalysis is considered a promising way to enhance C3-photosynthesis and photosynthetic water use efficiency (WUE) provided the introduced changes have little or no impact on other processes affecting photosynthesis such as leaf photochemistry or leaf CO2 diffusion conductances. However, the extent to which the factors affecting photosynthetic capacity are co-regulated is unclear. The aim of the present study was to characterize the photochemistry and CO2 transport processes in the leaves of three transplantomic tobacco genotypes expressing hybrid Rubisco isoforms comprising different Flaveria L-subunits that show variations in catalysis and differing trade-offs between the amount of Rubisco and its activation state.

Automated flow-based anion-exchange method for high-throughput isolation and real-time monitoring of RuBisCO in plant extracts.

In this work, a miniaturized, completely enclosed multisyringe-flow system is proposed for high-throughput purification of RuBisCO from Triticum aestivum extracts. The automated method capitalizes on the uptake of the target protein at 4°C onto Q-Sepharose Fast Flow strong anion-exchanger packed in a cylindrical microcolumn (105 × 4 mm) followed by a stepwise ionic-strength gradient elution (0-0.8 mol/L NaCl) to eliminate concomitant extract components and retrieve highly purified RuBisCO.

Physiological and morphological adaptations in relation to water use efficiency in Mediterranean accessions of Solanum lycopersicum.

The physiological traits underlying the apparent drought resistance of 'Tomàtiga de Ramellet' (TR) cultivars, a population of Mediterranean tomato cultivars with delayed fruit deterioration (DFD) phenotype and typically grown under non-irrigation conditions, are evaluated. Eight different tomato accessions were selected and included six TR accessions, one Mediterranean non-TR accession (NTR(M)) and a processing cultivar (NTR(O)). Among the TR accessions two leaf morphology types, normal divided leaves and potato-leaf, were selected.