Regulation of Rubisco activity during grain-fill in maize: possible role of Rubisco activase

1997 ◽  
Vol 128 (2) ◽  
pp. 155-161 ◽  
Author(s):  
E. MARTÍNEZ-BARAJAS ◽  
J. MOLINA-GALÁN ◽  
E. SÁNCHEZ de JIMÉNEZ
Keyword(s):  
Soluble Protein ◽  
Grain Filling ◽  
Rubisco Activase ◽  
Middle Part ◽  
Ribulose Bisphosphate Carboxylase ◽  
Rubisco Activity ◽  
Leaf Extracts ◽  
Bisphosphate Carboxylase ◽  
Grain Filling Period

Levels of ribulose bisphosphate carboxylase (Rubisco) and Rubisco activase were compared in leaves above the ear in two genetically related populations (Z0 and Z20) of maize (Zea mays L.). Z20 was obtained from Z0 after twenty agronomic selection cycles for grain yield improvement (c. 90% above Z0). Plants were cultivated in the highlands of Mexico and leaves were sampled weekly during the grain-filling period. Chlorophyll, soluble protein and Rubisco activity were measured. Chlorophyll and soluble protein content slowly decreased during this period, the former faster than the latter, with no significant differences between populations. During the first 40 days after anthesis, Rubisco activity was significantly greater in the high-yielding population (Z20), although Western blot analysis of Rubisco showed similar values for both populations within this period. However, the same analysis for Rubisco activase indicated a greater amount of this protein in the higher-yielding population (Z20) than the original one (Z0) during the early and middle part of the grain-filling period. The addition of Rubisco activase and an ATP-generating system to Z0 leaf extracts resulted in increased Rubisco activity. It was concluded that during grain-fill in maize, the level of Rubisco activase has a regulatory effect on Rubisco activity expression.

scholarly journals Four Mutant Alleles Elucidate the Role of the G2 Protein in the Development of C4 and C3 Photosynthesizing Maize Tissues

Genetics ◽  
2001 ◽  
Vol 159 (2) ◽  
pp. 787-797
Author(s):  
Lizzie Cribb ◽  
Lisa N Hall ◽  
Jane A Langdale
Keyword(s):  
Cell Types ◽  
Bundle Sheath ◽  
Primary Role ◽  
Ribulose Bisphosphate Carboxylase ◽  
Sheath Cell ◽  
Mesophyll Cells ◽  
Phenotypic Data ◽  
Bisphosphate Carboxylase ◽  
Bundle Sheath Cell

Abstract Maize leaf blades differentiate dimorphic photosynthetic cell types, the bundle sheath and mesophyll, between which the reactions of C4 photosynthesis are partitioned. Leaf-like organs of maize such as husk leaves, however, develop a C3 pattern of differentiation whereby ribulose bisphosphate carboxylase (RuBPCase) accumulates in all photosynthetic cell types. The Golden2 (G2) gene has previously been shown to play a role in bundle sheath cell differentiation in C4 leaf blades and to play a less well-defined role in C3 maize tissues. To further analyze G2 gene function in maize, four g2 mutations have been characterized. Three of these mutations were induced by the transposable element Spm. In g2-bsd1-m1 and g2-bsd1-s1, the element is inserted in the second intron and in g2-pg14 the element is inserted in the promoter. In the fourth case, g2-R, four amino acid changes and premature polyadenylation of the G2 transcript are observed. The phenotypes conditioned by these four mutations demonstrate that the primary role of G2 in C4 leaf blades is to promote bundle sheath cell chloroplast development. C4 photosynthetic enzymes can accumulate in both bundle sheath and mesophyll cells in the absence of G2. In C3 tissue, however, G2 influences both chloroplast differentiation and photosynthetic enzyme accumulation patterns. On the basis of the phenotypic data obtained, a model that postulates how G2 acts to facilitate C4 and C3 patterns of tissue development is proposed.

scholarly journals Photometric Measurements of Rubisco Activity in Leaves of Deciduous Fruit Crops

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 531A-531
Author(s):  
Lailiang Cheng ◽  
Leslie H. Fuchigami
Keyword(s):  
Net Photosynthesis ◽  
Photometric Method ◽  
Ribulose Bisphosphate Carboxylase ◽  
Fruit Crops ◽  
Rubisco Activity ◽  
Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate Carboxylase Oxygenase ◽  
Deciduous Fruit ◽  
Photometric Measurements

Ribulose bisphosphate carboxylase/oxygenase (Rubisco) initiates the photosynthetic carbon metabolism;therefore, its activity has been measured in many physiological studies. However, information on in vitro Rubisco activity from leaves of deciduous fruit crops is very limited and the reported activities are suspiciously low. We measured Rubisco activity in crude extracts of leaves of apple, pear, peach, cherry, and grape by using a photometric method in which RuBP carboxylation was enzymically coupled to NADH oxidation. Replacing polyvinylpyrrolidone with polyvinylpolypyrrolidone in the extraction solution significantly increased extractable Rubisco activity. Depending on species, freezing leaf discs in liquid nitrogen followed by storage at –80°C for only 24 hr reduced both initial and total Rubisco activity to 5% to 50% of that obtained from fresh leaves. Initial Rubisco activity from fresh leaf tissues of all species was well correlated with maximum Rubisco activity (Vcmax) estimated from gas exchange; an exception was pear, where initial Rubisco activity was higher than Vcmax. In most cases, initial Rubisco activity was approximately two to three times higher than net photosynthesis.

The Role of Fertilizer Management in the Development and Expression of Crop Drought Stress in Cereals under Mediterranean Environmental Conditions

1985 ◽  
Vol 21 (3) ◽  
pp. 209-222 ◽  
Author(s):  
J. D. H. Keatinge ◽  
P. J. H. Neate ◽  
K. D. Shepherd
Keyword(s):  
Drought Stress ◽  
Environmental Conditions ◽  
Crop Yields ◽  
Grain Filling ◽  
Fertilizer Management ◽  
Fertilizer N ◽  
Kernel Weights ◽  
Grain Filling Period ◽  
Heavy Nitrogen

SUMMARYThe development and influence of crop drought stress was examined in winter-planted small-grain cereals under Mediterranean environmental conditions. In two average or wetter than average years crop drought stress in the grain-filling period was greatly exacerbated by the addition of fertilizer (N and P) and this usually resulted in significantly lower kernel weights. Yet this reduction was not so substantial as to seriously affect crop yields. Total grain yields were largest in treatments receiving fertilizer, due to greater spike numbers and numbers of kernels per spike. But heavy nitrogen applications may promote the risk of a large proportion of small or shrivelled grains in a dry year.

scholarly journals A Transcriptomic Approach to Understanding the Combined Impacts of Supra-Optimal Temperatures and CO2 Revealed Different Responses in the Polyploid Coffea arabica and Its Diploid Progenitor C. canephora

2021 ◽  
Vol 22 (6) ◽  
pp. 3125
Author(s):  
Isabel Marques ◽  
Isabel Fernandes ◽  
Octávio S. Paulo ◽  
Fernando C. Lidon ◽  
Fábio M. DaMatta ◽  
...  
Keyword(s):  
High Temperatures ◽  
Enrichment Analysis ◽  
Ribulose Bisphosphate Carboxylase ◽  
Diploid Progenitor ◽  
Ribulose Bisphosphate ◽  
Rubisco Activity ◽  
Bisphosphate Carboxylase ◽  
Photosystems I And Ii ◽  
Photosynthetic Machinery ◽  
Transcriptomic Changes

Understanding the effect of extreme temperatures and elevated air (CO2) is crucial for mitigating the impacts of the coffee industry. In this work, leaf transcriptomic changes were evaluated in the diploid C. canephora and its polyploid C. arabica, grown at 25 °C and at two supra-optimal temperatures (37 °C, 42 °C), under ambient (aCO2) or elevated air CO2 (eCO2). Both species expressed fewer genes as temperature rose, although a high number of differentially expressed genes (DEGs) were observed, especially at 42 °C. An enrichment analysis revealed that the two species reacted differently to the high temperatures but with an overall up-regulation of the photosynthetic machinery until 37 °C. Although eCO2 helped to release stress, 42 °C had a severe impact on both species. A total of 667 photosynthetic and biochemical related-DEGs were altered with high temperatures and eCO2, which may be used as key probe genes in future studies. This was mostly felt in C. arabica, where genes related to ribulose-bisphosphate carboxylase (RuBisCO) activity, chlorophyll a-b binding, and the reaction centres of photosystems I and II were down-regulated, especially under 42°C, regardless of CO2. Transcriptomic changes showed that both species were strongly affected by the highest temperature, although they can endure higher temperatures (37 °C) than previously assumed.

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